Sikkim limps back to normalcy after quake
Saibal Gupta, PTI, Tung, Sep 24, 2011: A week after the 6.8 magnitude temblor ravaged its North district, Sikkim is limping back to normalcy with most of the connecting roads in the remote areas restored even as rains impeded rescue and relief work.
State HRD minister NK Pradhan told PTI that life is gradually returning to normal though rescue and relief operations are continuing in far-flung areas.
Pradhan said so far 1,489 houses have been found to be destroyed in the quake in worst-affected North district and the state government would provide all assistance for reconstruction of schools and houses.
"23 schools, mostly in North Sikkim, have been completely destroyed, while 190 schools have been partially damaged," he said, adding that steps would be taken to rebuild them.
Meanwhile, the 95 km-long Singtam-Chungthang has been cleared of landslides up to 86 kms, facilitating rescuers to the more remote areas hit by the quake.
Army sources said, a 6-km-stretch was cleared on the Chungthang side. "If the rest of the stretch is cleared of debris, the entire road from Singtam will be ready for normal traffic."
The two roads from Chungthang -- one to Lachen and another to Lachung -- were also being gradually cleared of boulders.
"So roads in affected areas closer to quake epicentre in North district are nearly cleared of debris by GREF (General Reserve Engineering Force) of the Army," he added.
Chief Minister Pawan Chamling toured affected areas of Mangan and visited patients in the hospital yesterday. He also assured them of government assistance.
Officials said 52 new relief camps have been started in different areas of Mangan, Naga, Limbu, Mangsila, Dikchu and Makha in North district and have provided shelter to about 2,000 people who trekked down here since yesterday from remote areas of Chungthang, Lachen and Lachung.
The camps, being run by NGOs, social organisations and National Disaster Response Force (NDRF), are also providing food, drinking water and medicine to people.
Meanwhile, a central team of the Health ministry arrived here during the day and visited the relief camps.
A member said the team's main purpose is to prevent outbreak of water-borne diseases like dysentery and diarrhoea.
Official sources said fresh land slips occurred in some areas of North district last night which was lashed by occasional rains.
However, no fresh damage was reported as yet due to rains.
Seven Kurseong residents still untraced in Sikkim
SNS, KURSEONG, 23 SEPT: Seven persons, all residents of the Dilaram Tea Estate near Kurseong, who were working at Munshithang in north Sikkim, have remained untraced since last Sunday. The family members of these persons have been spending sleepless nights since the earthquake struck Sikkim last Sunday with no information having come about their whereabouts.
It has been learnt that the missing persons have been at Munshithang near Chungthang in north Sikkim for the past several months. The untraced youths have been identified as Ajit Tamang (21), Dipesh Rai (22), Laxman Tamang (18), Kusal Rai (35), Kumar Gurung (51), Bhasker Rai (21) and Aasesh Rai (21).
The mother of Ajit Tamang, Mrs Santa Tamang, said that she had tried to contact her son several times over his mobile phone.
“I have got no response from his end yet. Even his friends cannot be contacted. We do not know whether he is alive or not,” she said. Ajit’s sister, Miss Suda Tamang, said that Ajit had left for Sikkim in last June. “He used to talk to us daily. But since the quake struck Sikkim he has not contacted us. Neither are we getting his line. We are apprehending the worst, though at the same time, we are hoping against hope that he is alive and remains trapped awaiting the rescue team to drag him out,” she said.
The same is the case with the near ones of the rest six who have remained untraced since last Sunday.
Mrs Savitri Rai, the mother of Mr Aashesh Rai, recounted the same story of frantic attempts to contact her missing son and the non response from his end. ”The last time I talked to him he told me that he would come home during the Diwali,” she said with tears moving down her cheeks.
The parents of the missing persons have filed a general diary at the Kurseong police station yesterday with the help of the local GJMM leaders. The police said that they are keeping in touch with the Sikkim administration for information.
The three MLAs from the Darjeeling Hills, who have visited Sikkim today, have met the officials there to gather information about the persons who hail from the Hills, have remained untraced in Sikkim.
Earthquake Update as at 1 P.M. Today
PIB, KalimNews, 24 Sept, 2011:
Ø The Number of deaths as reported by the State Government of Sikkim is 75. The break-up of death toll is as follows- East District- 13, North District-57, West District -04 and South District-01. 32 persons are hospitalized. The search and rescue operations by teams of NDRF, Army and officials of State Government are on.
Ø The details of damage reported by the State government (tentatively), in respect of houses, schools, hospitals are as follows:
# District No. of houses damaged No. of schools damaged No. of hospitals damaged
1 North NR NR 07 FD
2 South 1000 – FD 20 - FD NR
3 East 6000 - FD 201 - FD 23 FD
9000 – PD
4 West 1679 - FD 64- FD NR
TOTAL 8679 - FD 285 – FD 30 – FD
9000 – PD
NR – Not reported, FD – Fully damaged, PD – Partially damaged
Ø 05 teams of NDRF are deployed for search and rescue operations at Shipgyar, Biha and Bringbang Ramam, Lingzya and Dzongu villages in Mangan.
Ø Two teams of NDRF comprising 14 personnel and 16 personnel each are deployed at Chungthan and Lachung respectively.
Ø The doctors of the NDRF team deployed at Mangan with medical detachment are providing medial relief at the camp set up at Manul Mangan.
Ø 827 ITBP personnel are engaged in rescue operations and have also been running relief camps where rescued villagers have been given shelter.
Ø The State Govt. has opened 11 relief camps. 2700 and 550 people have been provided shelter into Army camps and ITBP camp (Pengong) respectively.
Ø A total of 5500 Army personnel located in Sikkim have been pressed into relief and r
rescue operations. Out of this 94 Army columns (strength of columns varies from 15-40 personnel each) are deployed for rescue operations. Rescue columns comprising 281 personnel deployed at Mangan have set up Integrated Command Centre.
Ø A medical team comprising 19 doctors (Surgeon – 4, Orthopedician – 6, Anaesthesian – 5, Neuro Surgeon – 2, and medicine – 2) have been deployed by the Ministry of Health, Government of India from Delhi on 19th September, 2011. A team of 10 doctors reached Chungthan on 20th September 2011 and remaining 9 doctors have been deployed at STNM Hospital, Gangtok.
Ø 940 civilians have been treated at Military hospitals. 28 civilians evacuated by Army helicopters are currently under treatment at Military Hospitals.
Ø Approx. 10,000 food packets have been air-dropped so far in the northern part of North District. Anothe 5000 food packets are ready for dropping at Chungthan, Lachung and Lachen after weather clears today.
Ø 15 helicopters of Army and Air Force have been pressed into relief work. For airdropping and reconnaissance, 150 sorties have been carried out so far.
Ø The following roads have been opened for traffic :
(i) National Highway 31-A from Siliguri to Gangtok
(ii) National Highway 55 - Darjeeling to Siliguri
(iii) Gangtok – Rangrang and Mangan
(iv)angan – Chugthan (upto 12 kms)
(v) Gangtok – Natu La. (56 km – 17 km open)
(vi)Damdim – Alagarh – Rishi – Pedong
(vii)Kupup – Natu La
(viii)Pedong – Kupup(ix)Rangpo – Rorathang.
Ø The following roads are still blocked :
(i)Chungthang – Lachen (22 kns.)
(ii)Chungthan – Lachung (24 kms)
Ø Border Roads Organisation (BRO) and Army Engineers are working for restoration of different roads.
Ø Landline and microwave links are operational. The present status of the operational mobile towers/BTS vis-à-vis total number is as follows. Vodafone-147(167), Reliance-41(54), Idea-42(42), Aircell-45(55), Airtel-65(69), BSNL-102(122).
Ø 3000 nos. of blankets, 400 nos. of tents, 200 stoves, 500 tarpaulin and 01 water purifier have arrived in Sikkim for distribution to the affected areas.
Sikkim quake: Toll rises to 135; 10,000 food packets airdropped
IE, Fri Sep 23 2011,Tung, North Sikkim: With 18 more bodies recovered in North Sikkim on Friday, the toll in Sunday's devastating quake rose to 135 even as hundreds of people in affected remote areas moved out of their villages fearing fresh tremors and landslides.
Rescue teams airlifted 22 stranded engineers and airdropped over 10,000 food packets in the quake-hit districts.
The disaster management control room in Gangtok said 17 bodies were recovered in the district since noon while one was found in the morning.
They said rescue workers reached villages surrounding Dzongu and Chungthang on foot as roads were still blocked by landslides, making the prospect of the toll rising further likely.
Scores of survivors trekked through difficult terrain and inclement weather from Lachung, Lachen and Chungthang reaching Tung, 10 km from Chungthang, one of the worst-hit areas, and recounted how huge boulders hurtled down the hills smashing their homes and leaving many dead and injured.
Over 10,000 food packets have been airdropped in the quake-hit areas of north Sikkim as two major roads connecting the region remained blocked due to landslides after Sunday¿s 6.8 magnitude earthquake.
Home Ministry officials today said another 5000 food packets are being sent to Chungthan, Lachung and Lachen.
With 18 more bodies were found under the debris in North Sikkim, the overall death toll has risen to 118 including 92 in the Himalayan state while West Bengal has reported 15 deaths, nine in Bihar, 11 in Nepal, seven in Tibet and one in Bhutan.
The number of dead in Sikkim has climbed to 74 in North District, East [13], West(4) and South (1).
Chief Minister Pawan Kumar Chamling has convened a high-level meeting with top officials to take stock of the situation and work out measures to further intensify relief operations.
More than 100 relief camps have been set up across the state where food supplies and other required materials have reached, Chief Secretary Karma Gyatso told reporters.
Many villages in the region have been wiped out and the chance of finding survivors was not bright.
After five days of the 6.8 magnitude temblor, stench of bodies buried in the rubble of houses hung heavy in the air. Heavy rains have worsened the situation for rescue workers.
"The pace of the rescue workers is slow due to disrupted road communication and heavy rains. But they are slowly gaining ground," a senior official said.
A five-storey building in Gangtok collapsed and four others adjoining it were also damaged extensively.
At least two persons were trapped under the debris of the collapsed house, which belongs to the state sports secretary, officials said.
The office of United Sikkim floated by football icon Baichung Bhutia was also housed in the building.
"We first escaped to Guma and spent the night there and next morning we started trekking through extremely difficult terrains covered with debris," said Karma Bhutia (30), who arrived in Tung from Lachen after trekking for two days.
Bhutia said several villagers had to crawl some distances in spells since they feared that the wet soil might cave in any moment if they walked on such stretches.
Army sources said 22 engineers and technicians of Poddar Construction, engaged by the Teesta Urja Project, were rescued from Tung, five days after their bus was stranded during the powerful tremor in Sikkim.
"Their bus was halted by a huge boulder and our men rescued them from Tung yesterday. They will be sent to Gangtok today," they said.
15 helicopters of Army and Air Force have been pressed into relief work. For airdropping and reconnaissance, 150 sorties have been carried out so far," an official said.
While nine vital roads, including National Highway 31A and National Highway 55, have been reopened for traffic, two roads Chungthang¿Lachen and Chungthan¿Lachung continued to remain blocked due to landslide.
Rain worsens plight of Sikkim earthquake victims
Soudhriti Bhabani Gangtok, India Today, September 24, 2011: Aggravating the earthquake tragedy that rattled Sikkim on Sunday, two residential highrises in Gangtok collapsed on Friday evening. At least four persons were critically injured in the incident, which occurred amid a downpour around 7.15 pm at Burtuk, two km north of Gangtok.
"So far, four persons have been evacuated and admitted to the STNM Hospital. The rescue operation is on," Gangtok SSP Prawin Gurung said.
Saying that the heavy rain was slowing down the rescue operation, Gurung added: "A five-storey building has caved in and the building adjacent to it has partially collapsed." Two more buildings in the same row also suffered damage under the impact of the falling structures, he added.
According to reports, at least one woman was trapped inside the second building till late at night even as the rescue work continued.
"The second building was vacant and there is no report of any injury," the police said.
The five-storey building was owned by Karmipi Bhutia, the mentor of former Indian football team captain Baichung Bhutia. The building also housed the offices of Baichung's football academy and an ATM kiosk.
The rescue operations continue in the remote parts of the quake- hit north Sikkim. The state administration officials are apprehensive that the toll figure, which touched the 75-mark on Friday, could inch up further.
Five NDRF teams have been deployed for the search and rescue operations at Shipgyar, Biha, Bringbang Ramam, Lingzya and Dzongu villages in Mangan. Two more NDRF teams, comprising 14 personnel and 16 personnel each, are deployed at Chungthan and Lachung respectively. Altogether, 827 ITBP personnel are engaged in the rescue operations, besides running relief camps for the rescued villagers.
The state government has opened more than 100 relief camps across the tremor-affected areas. Over 2,700 and 550 people have been provided relief and shelter at the army and ITBP camps (at Pengong) respectively.
While 57 persons have died in the north district alone, the toll figure in east, south and west Sikkim is 13, one and four respectively.
Since more than 80 per cent of the buildings in Gangtok have developed severe cracks, the residents have started fleeing the state capital after the aftershocks on Thursday night. "We don't want to stay here anymore.
All the buildings have been built alongside, with hardly any space in between. So if one building collapses, the one next to it is bound to fall down," 34-year-old Tenzing Sherpa, who went downhill with his family and parents on Friday, said.
Thousands of people spent a sleepless Thursday night on the streets of Gangtok after they felt the aftershock, measuring 3.9 on the Richter scale. The collapse of the two highrises has added to the panic already playing on the minds of the people in Gangtok.
Sikkim Chief Minister visits earthquake affected Mangan
Sikkim Mail (http://isikkim.com), Mangan/Gangtok, September 24: Sikkim Chief Minister Pawan Chamling made a visit to the North Sikkim District headquarter of Mangan. Enroute via Dikchu, he made several stops to talk to groups of people gathered who were in need. The first point of visit was the Ringhim Monastery of Mangan which was totally damaged. The Head Lama incharge, Acharya Aptuk Lepcha, made a fervent plea of repair and rehabilitation to the CM. Other people also petitioned the Chief Minister. The Chief Minister promised to rebuild the monastery and requested the area MLA to start the program of rebuilding.
In all his comments to the people the CM was emphatic about clearing all doubts and fears that people were having about the recurrence of another quake of this magnitude. He said that the likelihood of another one coming in a hurry is unlikely though there will be shocks. He also warned that there is danger from landslips and falling boulders as the earth has shaken and boulders have become loose. He also appealed to everyone to help in the process of overcoming this trauma especially those who have lost their loved ones.
He also outlined all the relief measures. He emphasized the need to get the relief immediately to those in need. He said he was empowering all Panchayats and Dzumsas directly and handing over Rs. 5 Lakh to every Panchayat unit and Rs.10 Lakh to each Dzumsa. This will enable them to take immediate action to operate relief and rehabilitation without bureaucratic delay. Furthermore, each Subdivision and BDO will be given Rs. 5 Lakhs and the District Collector Rs. 50 Lakhs. This kind of fund flow will ensure that there is alacrity in providing relief to those in dire need. This he mentioned is being done and it comes at a time when most of the places have already been reached. He further promised to rebuild all the homes of those whose homes had been demolished.
He requested all the MLAs, Panchayats, Pipons and other Government functionaries to work hard and with feeling. He also said that they need to work from their level without waiting for any direction from the top especially when it comes to giving relief to the affected people.
He visited the relief camps which are being run by some local volunteers. He sent out a strong message to the labourers who were there to stay back. He said that there is no reason to fear when the Government was at hand to help them.
The Chief Minister distributed relief directly to the people who were affected and who had assembled there. Those who were unable to reach, their relief cash was left with the District Collector. The Chief Minister was accompanied by the Minister for Roads and Bridges, R. B. Subba; the Minister for Health, D. N. Thakarpa, the Minister for Power, Sonam Lepcha and MLA of Mangan Tashi Wangdi Lepcha. Lok Sabha MP, P. D. Rai, was also present along with other dignitaries and party people.
Rumours add to quake-hit Sikkim's woes
Karma Paljor, CNN-IBN: Gangtok: It has been almost a week since a powerful earthquake struck Sikkim. 75 people have died so far. But rumours and false reports of 17 people being buried alive in a tunnel collapsed caused many to panic.
CNN-IBN's team travelled to a hydroelectricity project site in Chungthang and found out if all was well and that the tunnel was intact and workers were unharmed.
Rumours spread thick and fast that hundreds were buried alive inside tunnels soon after the earthquake jolted the Northeast on the September 18.
One rumour said that 17 were dead, 10 were injured and one was still missing at the Teesta 3 Hydroelectric Project, a company that lost the most men last Sunday.
But when CNN-IBN visited the project site, the team found the tunnels to be intact. One tunnel was in fact being used by the army to evacuate people.
Workers here said that the deaths reported took place not there but at another site.
Nature soothes quake-ravaged
ARUNANGSU ROY CHWODHURY, TH, TOONG, September 23, 2011: A rainbow brings cheer to Sikkimese amid pain and sorrow - On Friday morning, the road was cleared up to Toong from Mangan, headquarters of North Sikkim district. Five days after the massive earthquake that struck the region, it came as a big relief to local residents as well as the Army personnel who were engaged in the gargantuan task of clearing the roads.
From Toong, the road bifurcates towards two quake-ravaged destinations, Shipgyre and Chunghthang.
“The real fight starts from here though. What we have done so far will be nothing in comparison to the challenge that lies ahead,” Sanjay Sharma, Commanding Officer of 52 Engineer Regiment of the Army asserted.
The fresh jolt of earthquake late on Thursday has left life here further vulnerable. Just when the residents of North Sikkim district were about to emerge from last Sunday's nightmare to start life afresh, the initiative got paused once again.
Ashok Subba was searching for remnants of his makeshift home at Toong amid rubbles. The house was flattened under tonnes of debris that rolled down the mountain side during the earthquake. One of his relatives was injured.
He suddenly found a packet full of photographs in the wreckage and began showing pictures of his injured relative.
Two girls, Dali Sherpa and Nagpa Diki, were busy loading their belongings on a lorry to shift to a safer place. Dali's mother, Sonu, was waiting for them in Voong Basti under Naga gram panchayat. They have shifted to a rented house here. Sonu was silent throughout. Grief visible in her eyes, she went about making their new home liveable.
Dali, a Class X student, was injured in a massive landslide and still feels pain at the back of her head. Her school closed down after the quake and none knows when it will reopen.
People from Chunghthang, Lachen, Paigong and Lachung continue trekking towards Mangan, braving the treacherous mountain and forest paths to reach to safer places.
Shering, who trekked down from Chunghthang to Toong this morning, said that the Teesta Urja project tunnel is in good shape and he had reached Chungthang by walking through the tunnel.
He went to Chunghthang on Thursday to find his friend who has not communicated since last Sunday.
It started raining while returning to Mangan from Toong. When the rains stopped, a middle-aged woman's happy voice drew my attention. She was calling her son to show the rainbow that had appeared on the horizon.
Maybe it was the first time that a rainbow was visible in North Sikkim after the quake hit the district as it immediately led people to forget all their fear and pain experienced over the past few days and become delighted.
And, needless to say that nature only can do it!
Housing worry daunting as Sikkim limps back to normality
SUSHANTA TALUKDAR, TH, SAMDUNG (SIKKIM), 23 Sept: Ward-wise teams set up for door-to-door assessment of quake damage- Sikkim is limping back to normality barring the worst-hit and inaccessible quake-hit areas. However, for many affected people like Amrita Tewari, who works as a home guard to feed her two children and her unemployed husband, the worry is to find a safe shelter as their houses have been rendered unsafe by the September 18 quake.
In a day or two, Ms. Tewari is likely to get notice from the local panchayat asking her to vacate the damaged house. Construction of a new house is a worry that haunts the woman, who was on route lining duty on Friday in view of Chief Minister P.K. Chamling's visit to Mangan, headquarters of North District.
“Even after cracks showed up in our building, we decided to continue living in the house as we did not want to go to a relief camp. But, I know, once the official notice is served, authorities will not be responsible if my building collapses. I am in a dilemma,” Ms. Tewari told The Hindu as she took a break to have tea in roadside restaurant after the Chief Minister's convoy had crossed the area.
The local MLA of Tumen-Limgi, Ugen T Gyatso Bhutia, assured panchayat members and residents that the State government would provide all help for rehabilitation. About 400 people of his constituency, whose houses were damaged in the September 18 quake, have taken shelter in eight relief camps. The legislator said the government decided to provide dwellings under the Chief Minister's Rural Housing scheme to all those whose houses had been rendered unsafe. Ward-wise teams were formed in each panchayat for a door-to-door assessment of the quake damage and to ascertain the number of houses rendered unsafe. The people had been advised to immediately vacate unsafe houses, he said.
Amid human misery, even the Kanchenjunga appears lifeless
ARUNANGSU ROY CHOWDHURY, TH, MANGAN, September 23, 2011: For the quake-hit people of Chunghthang, it was a long, arduous trek to safety-
The drizzle turned into a heavy shower. It was only 9 a.m. As thick clouds started wrapping themselves around the Himalayan range, fears of more cloudbursts and landslips grew among the hill people. It could make life more vulnerable in the coming days.
Bulldozers were unable to clear the giant rocks that blocked the road leading to Chunghthang from Mangan due to a landslip. Personnel of the General Reserve Engineering Force (GREF) and the Army have been engaged in the gargantuan task of moving the rocks from the road for the last two days.
The road near Tung, located about 15 km from Mangan, was finally cleared on the day for vehicular movement. Chungthang is another 15 km from Tung. After Tung, the road itself has disappeared as it has slid down the steep hill.
People were stranded on both sides of the landslip area — waiting for Army personnel's nod to climb the rocks and cross the site. The moment the permission was granted, people jumped over the rocks.
One among the crowd was climbing the rocks with bare feet. He was coming from the Chungthang-end and hurriedly crossed over the loose boulders to reach the other side and wait for his friends. When asked about the situation in the Chungthang area, he began to cry. “Please don't ask me anything about Chungthang. By the grace of God, I am alive,” he said.
He was Bishnudhari Das — a contract labourer of the Navayuga Engineering Company (NEC) at Chungthang. On the day of the quake, he was present at the project site. He had run for his life after seeing some of his colleagues getting crushed under the collapsed buildings.
Bishnudhari did not even care to put on his shoes for the long trek through dense forests and rocky terrain: “My house was flattened and I had no option but to leave behind all my belongings. I just ran for my life.”
Another NEC worker, Bikas, was seen struggling to trek along with his wife Nirmala and their four-year-old son. They spent two sleepless nights under the open sky since Sunday before finally mustering the courage for the long, arduous trek.
“We had to cross a turbulent river by holding on to a rope. The forest path was full of leeches. We just want to reach home safely,” Nirmala said fighting back her tears.
Kuldeep Singh, a Subedar of the GREF, narrated the tale of 22 lucky passengers of an ill-fated bus that remained stuck under rubble for two days before the passengers were rescued.
Life is very precious here. When I opened my hotel window at Mangan on Thursday morning, the majestic view of the Kanchenjunga's snowy peak mesmerised me. But the day's traumatic experiences have taught me that nothing can be more beautiful than life itself — even the Kanchenjunga appears lifeless amid such human misery.
Buildings flout seismic norms
Prithvijit Mitra, TNN | Sep 24, 2011:KOLKATA: Even as the Geological Survey of India (GSI) is contemplating an advisory for Kolkata, structural experts have warned that basic construction norms prescribed by the Bureau of Indian Standards (BIS) were being rampantly flouted in the city.
Structures, they pointed out, were being erected without a frequency study of the site and buildings, while beams, bricks, steel and other reinforcements used were not being made strong enough to withstand tremors. It could be risky in the long-run, they said.
The Sikkim earthquake on Sunday made several tall structures in Kolkata sway. Some even developed cracks following the tremor. GSI scientists pointed out that soft floors or vacant ground floors reserved for car parking could be responsible for the damages since they allow shock waves to travel freely, hitting the pillars with a great intensity. "While this could be technically correct, it should also be considered that car parks are permitted in seismic resistant building designs approved by the BIS. If you go by standard 1893 - the BSI code for structures - car parks are safe provided the other norms are adhered to. Unfortunately, this is not happening in most structures that are mushrooming across the city," said Anjan Datta, structural expert.
Standard 1893 lays down a seismic frequency chart that requires a measurement of response frequency and peak ground acceleration of structures in case of a tremor. It also recommends a particular thickness and density for column and beam junctions in high-rises. They should be ductile enough to absorb shocks, it says. "While bigger projects stick to the norms, they are few in number. There is no vigil on the innumerable smaller buildings that are coming up everywhere. A look at the structures makes it clear that they have bypassed the safety rules," added Datta. Buildings in Howrah, for instance, were guilty of flouting norms most blatantly, Datta said.
According to standard 1893, 550D-grade steel has to be used in buildings. These are shock-absorbent and ductile. Brick walls must be rejected in favour of reinforced concrete walls. "In case a brick wall is used, there should be hybrid netting in every third layer. This is because the mortar used between the bricks can't withstand a severe shock. There is none to check if these are being done," said Datta.
The GSI has prepared an advisory on the basis of data collected on Kolkata's underground composition from various sources. It suggests the exclusion of soft floors and recommends adequate distance between buildings other than making them conventional, symmetrical and solid structures, sans fancy frills. No seismic zonation study, however, has yet been done to assess the city's vulnerability to quakes. "There are numerous buildings which don't stick to these basic rules. So far as the walls and beams are concerned, there has to be a stricter vigilance. It can happen only if we have an advisory for the city. We are planning to take it up with the BSI," said a GSI official.
Dragon's threat makes quake-hit Sikkim suffer
Nearly a week after the September 18 earthquake in Sikkim, relief hasn't yet reached the interior areas of this tiny state.
Jayanta Gupta, TNN, Sep 24, 2011: KOLKATA: Nearly a week after the September 18 earthquake in Sikkim, relief hasn't yet reached the interior areas of this tiny state. Reason: The state lacks infrastructure, particularly roads and airfields, which would have speeded up succour to the people of the state.
Advanced landing grounds and roads had not been developed as mandarins in Delhi feared such infrastructure would help the Chinese over-run the region in the event of a repetition of the 1962 border conflict.
The Air Force is still finding it difficult to move men and equipment to the worstaffected areas. Eastern Air Command sources said mobilization would have been faster had the IAF managed to land AN-32 or a similar large transport aircraft close to Mangan, Chungthang or Lachung.
"Delhi woke up from its slumber only recently to realize that infrastructure development is required in the northeast. This shift from its Pakistan-centric approach has led to development of facilities in Assam and Arunachal Pradesh. It may take some more time for infrastructure to be built in north or east Sikkim," said a state government source.
The Union defence ministry was able to successfully reason that Sikkim should be left underdeveloped for "strategic" purposes. The fear was if China were to carry out a lightning strike across the Line of Actual Control (LAC) in north Sikkim, it would be able to take the entire state by using the infrastructure built by the Union or the state government.
"The philosophy was that should such a strike take place and Indian forces be compelled to fall back, the Chinese should not get access to infrastructure that would help consolidate its position," said the official.
"In reality, this was a ridiculous strategy. China is rapidly building infrastructure on the Tibet side and lack of infrastructure on our side won't deter them. It is a matter of concern that no ALGs exist in Sikkim," said another official.
The Army is now considering a Mountain Strike Corps and may station ultralight howitzers and light tanks along the LAC. Now, IAF might also consider ALGs in north and east Sikkim.
A detailed report on the earthquake (M:6.8) of 18thSeptember, 2011 in Sikkim-Nepal border region
An earthquake of magnitude 6.8 occurred on 18th September at 18:11 hrs IST in
Sikkim-Nepal Border region. The preliminary hypo-central parameters of this earthquake, as estimated by the Seismic Monitoring Network of India Meteorological Department (IMD) are given below:
Date of occurrence : 18/09/2011
Time : 18:11 hrs (IST)
Magnitude : 6.8
Focal depth : 10 Km
Epiecentre
Latitude & Longitude : 27.7o N & 88.2o E
Region : Sikkim-Nepal Border region.
The event, which comes under the category of “Moderate earthquake”, was also reported widely felt in Sikkim, Assam, Meghalaya, northern parts of West Bengal, Bihar, parts of other eastern and northern regions of India. The epicentre lies in a seismically known and active belt called, Alpide-Himalayan seismic belt. The location of the earthquake is shown on the seismicity map of Sikkim and neighbouring areas given at Annexure-1. The main shock was followed by several aftershocks of low intensity and a few significant aftershocks (M≥4.0) located by the network, as detailed below. It may, however, be mentioned that the magnitude and frequency of aftershocks will reduce with the passage of time.
S.No. Date Time of aftershocks
Hr:Min (In IST)
Magnitude
1. 18.09.2011 18 :42 5.0
2. 18.09.2011 19:24 4.5
3. 19.09.2011 03:22 4.2
The earthquake source parameters have been disseminated to all concerned state and
central government agencies related with initiating relief and rescue operations in the region.
The information is also put on IMD‟s website for public use. The aftershock activity is being continuously monitored and information on significant aftershocks is being transmitted to all the concerned agencies.
The source parameters of the event are estimated using data of a total of 77 seismic stations in India and across the globe spread more or less in all azimuths (Annexure-2). The details of various magnitude estimates are given in Annexure-3. The preliminary faulting mechanism of the subject earthquake, as estimated through Centroid Moment Tensor (CMT) and Moment Tensor (MT) solutions are given in (Annexure- 4 & -5). The faulting mechanism indicates reverse faulting associated with the tectonic processes related to the collision of Indian and Eurasian plates along the major thrusts in the region.
The centroid moment depth indicated by the CMT solution (10 km.) for the present event matches well with the hypo-central estimates. The CMT and MT solutions are obtained from waveform modelling making use of Body and Surface waves respectively. The process essentially involves in simulating the synthetic seismograms by assuming a known source, path and instrumental characteristics. These synthetic seismograms are then matched with the observed ones at various stations in an attempt to arrive at the characteristics of the source, which produces the best synthetic seismograms matching with the observed ones.
2. A slight magnitude earthquake (M:3.9) also occurred at 06 hours 22 minutes IST on 19th September, 2011 in the Latur district of Maharashtra. This event is located about 1500 kms away from the epicenter of the earthquake in Sikkim-Nepal border region of 18th September, 2011 and hence felt not directly related to it.
3. Strong Motion Accelerographs (SMAs), meant for recording strong ground vibrations of the kind experienced during the subject event, are deployed by academic institutions, viz., IIT (Roorkee), IIT (Kharagpur), etc. in the Himalayan region including northeast India through sponsored projects supported by MoES. These data sets would provide valuable information for designing earthquake resistant structures in the region in future.
4. Past seismicity of the region:
Historical and instrumentally recorded data on earthquakes show that the Sikkim and adjoining area lies in a region prone to be affected by moderate to great earthquakes in the past. Some noteworthy earthquakes that have affected the region are:
(i) Cachar earthquake of 10.01.1869 (M: 7.5),
(ii) Shillong plateau earthquake of 12.06.1897 (M: 8.7),
(iii) Dhubri earthquake of 02.07.1930 (M: 7.1),
(iv) Bihar-Nepal Border earthquake of 15.01.1934 (M: 8.3),
(v) Arunachal Pradesh – China Border earthquake of 15.08.1950 (M: 8.5),
(vi) Nepal-India Border earthquake of 21.08.1988 (M: 6.4)
(vii) Sikkim earthquake of 14.02.2006 (M: 5.7)
(viii) Bhutan earthquake of 21.09.2009 (M:6.2)
The Sikkim and adjoining region is known to be part of the seismically active region of the, Alpide-Himalayan global seismic belt‟, with four great earthquakes of the world of magnitude 8.0 and above occurring in this region. The occurrence of earthquakes in the region is broadly associated with the tectonic activity along well known faults in the Himalayas, namely, Main Boundary Thrust (MBT), Main Central Thrust (MCT). Other
prominent geological / tectonic features in and around Sikkim include: Tista lineament,
Kunchenjunga lineament, Purnea-Everest lineament, Arun lineament and Dhubri fault in the southeast.
In the seismic zoning map of India prepared under the auspices of Bureau of Indian Standards (BIS code IS: 1893: Part I 2002), by a committee of experts representing various scientific institutions including India Meteorological Department (IMD), the entire area of Sikkim lies in Zone IV. The seismic Zone IV is broadly associated with seismic intensity VIII on the Modified Mercalli Intensity (MMI) scale. It may be mentioned that the seismic intensity VIII on MMI scale corresponds to a horizontal ground acceleration range of 51-350 cm / sec 2
or an average acceleration of 172 cm / sec 2
in any direction. The ground acceleration and hence the intensity of an earthquake at a place depends on magnitude of earthquake, distance from the focus, duration of earthquake, type of underlying soil and its damping characteristics and liquefaction potential. The damage to the buildings founded on soft soil or filled up earth is higher than that in the similar type of buildings having their foundation on hard bedrock. Also, the damage will be higher for higher magnitude and long duration earthquakes, less epicentral distance soft soil conditions and areas with high liquefaction potential.
Presently, there is no scientific technique available anywhere in the world to predict occurrence of earthquakes with reasonable degree of accuracy with regard to space, time and magnitude. It is, therefore suggested that appropriate steps may be taken to ensure that the dwellings and other structures in the region are designed and constructed as per guidelines laid down by Bureau of Indian Standards (BIS) to minimize the losses caused by earthquakes.
The choice of seismic factor to be adopted for designing and engineering the structures depends on horizontal ground acceleration and various other factors including type of structures, the ground conditions and also importance of structures. For important and critical structures, site specific spectral studies have to be carried out before assessing the seismic design parameters. Suitable seismic design parameters may be adopted as per recommendations of National Committee on Seismic Design Parameters (NCSDP) for designing and engineering Hydroelectric Projects.
5. Causes of earthquakes:
Earthquakes are the result of a process, wherein the underground rocks suddenly
break, along a plane of weakness called „fault’, when the prevalent stresses exceed the elastic strength of the rock. The buildup of stresses and subsequent release of the strain energy in the form of earthquakes is a continuous process, which keeps repeating in geological time scale.
A number of theoretical assumptions that explain the forces, which cause accumulation of stresses inside the earth include: drifting of continents and mountain building process, shortening of Earth‟s Crust due to cooling and contraction, disturbance of mass distribution on the Earth‟s surface as a result of erosion of high lands and deposition of sediments in the sea and generation of heat by radioactive material inside the Earth‟s Crust.
6. Classification of earthquakes:
Based on magnitude (M), earthquakes may be classified as Micro- (M<3.0), Slight- (M:3.0 -4.9), Moderate- (M:5.0-6.9), Great- (M:7.0-8.0) and Very great- (M>8.0).
Earthquakes may also be classified as shallow-focus, intermediate-focus and deep-focus depending upon their focal depths. Shallow-focus earthquakes, which constitute about 80% of total energy release on the globe, have their foci at a depth between 0 and 70 km. and occur along collision and subduction zones, oceanic ridges and transform faults.
Intermediate-focus earthquakes (focal depth between 71 and 300 km.) and deep-focus
earthquakes (focal depth greater than 300 km.) occur in subduction zones, such as AndamanNicobar island region and northeast India. Most earthquakes originate within the crust and beneath the Moho, the number falls abruptly and dies down to zero at a depth of about 700 km. On an average, it is expected that about two earthquakes of M~8.0, ~20 earthquakes of M~7.0, ~100 earthquakes of M~6.0 and ~3000 earthquakes of M~5.0 are likely to occur every year over the globe. A list of significant earthquakes in the recent past in and around India is given below:
Uttarkashi earthquake of October 20, 1991 (M: 6.6).
Latur earthquake of September 30, 1993 (M: 6.3).
Jabalpur earthquake of May 22, 1997 (M: 6.0).
Chamoli earthquake of March 29, 1999 (M: 6.8).
Bhuj earthquake of January 26, 2001 (M: 7.7).
Sumatra earthquake of December 26, 2004 (Mw:9.3)
Muzaffarabad earthquake of October 8, 2005 (Ms:7.6)
7. Seismic Zoning of India:
Bureau of Indian Standards [IS-1893 (Part-1): 2002], based on various scientific inputs
collected from a number of agencies, has grouped the country into four seismic zones, viz.
Zone-II, -III, -IV and –V. Of these, Zone V is seismically the most prone region, while zone
II is the least. The Modified Mercalli (MM) intensity, which measures the impact of the
earthquakes on the surface of the earth, broadly associated with various zones is as follows:
Seismic Zone MM Intensity
II (Low intensity zone) VI (or less)
III (Moderate intensity zone) VII
IV (Severe intensity zone) VIII
V (Very severe intensity zone) IX (and above)
Broadly, Zone-V (12% of land) comprises of entire northeastern India, parts of Jammu
and Kashmir, Himachal Pradesh, Uttarakhand, Rann of Kutch in Gujarat, parts of North
Bihar and Andaman & Nicobar islands. Zone-IV (18%) covers remaining parts of Jammu & Kashmir and Himachal Pradesh, Union Territory of Delhi, Sikkim, northern parts of Uttar Pradesh, Bihar and West Bengal, parts of Gujarat and some portion of Maharashtra near the west coast and Rajasthan. Zone-III (27%) comprises of Kerala, Goa, Lakshadweep islands, remaining parts of Uttar Pradesh, Gujarat and West Bengal, parts of Punjab, Rajasthan, Madhya Pradesh, Bihar, Jharkhand, Chhatisgarh, Maharashtra, Orissa, Andhra Pradesh, Tamilnadu and Karnataka. Zone-II (43%) covers remaining parts of the country.
8. Seismic Hazard and Risk Microzonation:
Microzonation is the process of dividing a geographic domain into small units of likely uniform hazard level and nature. This classification is done based on Geoscientific, Geotechnical, Seismological and Engineering seismological parameters. The Hazard micro zone map is transformed into seismic risk microzonation map with inputs on Vulnerability of Built environment and Anthropological / Sociological inputs. As earthquake prediction is not possible precisely in time and space, seismic Hazard microzonation provides an important tool for generating parameters for site specific structural designing, land use planning and disaster mitigation. Seismic microzonation studies have been completed for Delhi (1:50,000 scale), Guwahati (1:25,000 scale), Sikkim (1:25,000 scale) and Bangalore city (1:25,000 scale).
Microzonation map for NCT of Delhi is further being refined at 1:10,000 scale. It is planned to take up microzonation studies for all State Capitals and cities with a population density of half a million lying in Zones III, IV and V. The work will be taken up in phased manner and 30 cities have been indentified to start with. In this connection, detailed guidelines have been prepared for standardization of procedures / methods for adoption taking up these studies.
9. Disaster mitigation:
Loss of lives during an earthquake is mostly due to damage or collapse of houses/ structures.
However, any structure can bear the vibration from an earthquake if it has enough strength and sturdiness. Bureau of Indian Standards (BIS) has published criterion for construction of earthquake resistant structures. The design of structure should be such that the whole structure behaves as one unit at the time of vibration rather than assemblage of parts.
Important structures like hospitals, fire stations etc. should be made earthquake resistant.
However, it is not economical to demolish and reconstruct most of the poorly built structures; for such poorly built structures BIS has prepared guidelines for their retrofitting. In addition to this, HUDCO & BMTPC have also published guidelines and brochures for construction and retrofitting of buildings. Further, losses due to earthquakes can be considerably reduced through proper planning and implementation of pre- and post-disaster preparedness and management strategies by respective state government agencies by working out the possible earthquake effects for various seismic zones.
10. National Program on Earthquake Precursors (NPEP)
It is now recognized that earthquake generation processes are so complex and site specific that often, no two different tectonic environments behave in similar manner in terms of providing clues about the ongoing physical processes in the earthquake source region. It is, thus, necessary to adopt an integrated approach of generation, assimilation and analyses of a variety of earthquake precursory phenomena in critical seismotectonic environments in the country in a comprehensive manner. Towards meeting this objective, a National Program on Earthquake Precursors (NPEP) has been initiated recently by MoES through a multiinstitutional and multi-disciplinary mechanism.
As part of this, a suite of Multi-Parametric Geophysical Observatories (MPGOs) have been set up at Ghuttu, Shillong and Koyna to monitor various earthquake precursory phenomenon such as, seismicity patterns, crustal deformations, gravity anomalies, electrical resistivity changes, electromagnetic perturbations, water level changes, geo-hydrochemical changes, Radon and Helium anomalies and thermal anomalies, etc. Preliminary analyses of these data sets have provided useful leads on the ongoing tectonic processes in the Koyna-Warna region. It is proposed to intensity these investigations during the XII FYP.
11. Deep drilling program in Koyna region
The Koyna Dam located in Maharashtra, western India is the most outstanding example of Reservoir Triggered Seismicity (RTS), where triggered earthquakes have been occurring in a restricted area of 20x30 sq km since the impoundment of Shivajisagar Lake in 1962. These include the largest triggered earthquake of M~6.3 on Dec 10 1967, 22 earthquakes of M>5, about 200 earthquakes of M~4, and several thousand smaller earthquakes since 1962.
Considering the importance of deep borehole investigations, it is proposed to undertake a suite of observations in deep borehole(s) in the Koyna area. The work will be carried out in collaboration with ICDP and the observations will include stress regime, pore fluid pressure and its variations, heat flow and its variation, orientation of faults, study of chemical properties of fluids, before, during and after earthquake. The proposed investigations through the borehole will facilitate i) observation and analysis of data, generated through the operation of borehole for 4-5 year of time, when it is anticipated that a few earthquakes of magnitude ~3 would occur in the immediate vicinity of borehole, ii) continuous observation to study the data in the far and near field of the earthquake and temporal variation w.r.t. occurrence of earthquake and iii) development of a model of RTS mechanism.
12. The critical structures viz., nuclear power plants and dams in the country are designed taking into consideration the past seismicity and the expected ground motions in the region, estimated through a detailed site specific analysis using probabilistic and deterministic approaches carried out by earthquake engineering community.13. Efforts are being made to improve the understanding of earthquake processes and their impacts towards better management and mitigation of the effects of earthquakes in future. A document detailing the proposals planned to be taken up during the XII FYP is attached for kind information.
Earthquake Update as at 1 P.M. Today
PIB, KalimNews, 24 Sept, 2011:
Ø The Number of deaths as reported by the State Government of Sikkim is 75. The break-up of death toll is as follows- East District- 13, North District-57, West District -04 and South District-01. 32 persons are hospitalized. The search and rescue operations by teams of NDRF, Army and officials of State Government are on.
Ø The details of damage reported by the State government (tentatively), in respect of houses, schools, hospitals are as follows:
# District No. of houses damaged No. of schools damaged No. of hospitals damaged
1 North NR NR 07 FD
2 South 1000 – FD 20 - FD NR
3 East 6000 - FD 201 - FD 23 FD
9000 – PD
4 West 1679 - FD 64- FD NR
TOTAL 8679 - FD 285 – FD 30 – FD
9000 – PD
NR – Not reported, FD – Fully damaged, PD – Partially damaged
Ø 05 teams of NDRF are deployed for search and rescue operations at Shipgyar, Biha and Bringbang Ramam, Lingzya and Dzongu villages in Mangan.
Ø Two teams of NDRF comprising 14 personnel and 16 personnel each are deployed at Chungthan and Lachung respectively.
Ø The doctors of the NDRF team deployed at Mangan with medical detachment are providing medial relief at the camp set up at Manul Mangan.
Ø 827 ITBP personnel are engaged in rescue operations and have also been running relief camps where rescued villagers have been given shelter.
Ø The State Govt. has opened 11 relief camps. 2700 and 550 people have been provided shelter into Army camps and ITBP camp (Pengong) respectively.
Ø A total of 5500 Army personnel located in Sikkim have been pressed into relief and r
rescue operations. Out of this 94 Army columns (strength of columns varies from 15-40 personnel each) are deployed for rescue operations. Rescue columns comprising 281 personnel deployed at Mangan have set up Integrated Command Centre.
Ø A medical team comprising 19 doctors (Surgeon – 4, Orthopedician – 6, Anaesthesian – 5, Neuro Surgeon – 2, and medicine – 2) have been deployed by the Ministry of Health, Government of India from Delhi on 19th September, 2011. A team of 10 doctors reached Chungthan on 20th September 2011 and remaining 9 doctors have been deployed at STNM Hospital, Gangtok.
Ø 940 civilians have been treated at Military hospitals. 28 civilians evacuated by Army helicopters are currently under treatment at Military Hospitals.
Ø Approx. 10,000 food packets have been air-dropped so far in the northern part of North District. Anothe 5000 food packets are ready for dropping at Chungthan, Lachung and Lachen after weather clears today.
Ø 15 helicopters of Army and Air Force have been pressed into relief work. For airdropping and reconnaissance, 150 sorties have been carried out so far.
Ø The following roads have been opened for traffic :
(i) National Highway 31-A from Siliguri to Gangtok
(ii) National Highway 55 - Darjeeling to Siliguri
(iii) Gangtok – Rangrang and Mangan
(iv)angan – Chugthan (upto 12 kms)
(v) Gangtok – Natu La. (56 km – 17 km open)
(vi)Damdim – Alagarh – Rishi – Pedong
(vii)Kupup – Natu La
(viii)Pedong – Kupup(ix)Rangpo – Rorathang.
Ø The following roads are still blocked :
(i)Chungthang – Lachen (22 kns.)
(ii)Chungthan – Lachung (24 kms)
Ø Border Roads Organisation (BRO) and Army Engineers are working for restoration of different roads.
Ø Landline and microwave links are operational. The present status of the operational mobile towers/BTS vis-à-vis total number is as follows. Vodafone-147(167), Reliance-41(54), Idea-42(42), Aircell-45(55), Airtel-65(69), BSNL-102(122).
Ø 3000 nos. of blankets, 400 nos. of tents, 200 stoves, 500 tarpaulin and 01 water purifier have arrived in Sikkim for distribution to the affected areas.
Sikkim quake: Toll rises to 135; 10,000 food packets airdropped
IE, Fri Sep 23 2011,Tung, North Sikkim: With 18 more bodies recovered in North Sikkim on Friday, the toll in Sunday's devastating quake rose to 135 even as hundreds of people in affected remote areas moved out of their villages fearing fresh tremors and landslides.
Rescue teams airlifted 22 stranded engineers and airdropped over 10,000 food packets in the quake-hit districts.
The disaster management control room in Gangtok said 17 bodies were recovered in the district since noon while one was found in the morning.
They said rescue workers reached villages surrounding Dzongu and Chungthang on foot as roads were still blocked by landslides, making the prospect of the toll rising further likely.
Scores of survivors trekked through difficult terrain and inclement weather from Lachung, Lachen and Chungthang reaching Tung, 10 km from Chungthang, one of the worst-hit areas, and recounted how huge boulders hurtled down the hills smashing their homes and leaving many dead and injured.
Over 10,000 food packets have been airdropped in the quake-hit areas of north Sikkim as two major roads connecting the region remained blocked due to landslides after Sunday¿s 6.8 magnitude earthquake.
Home Ministry officials today said another 5000 food packets are being sent to Chungthan, Lachung and Lachen.
With 18 more bodies were found under the debris in North Sikkim, the overall death toll has risen to 118 including 92 in the Himalayan state while West Bengal has reported 15 deaths, nine in Bihar, 11 in Nepal, seven in Tibet and one in Bhutan.
The number of dead in Sikkim has climbed to 74 in North District, East [13], West(4) and South (1).
Chief Minister Pawan Kumar Chamling has convened a high-level meeting with top officials to take stock of the situation and work out measures to further intensify relief operations.
More than 100 relief camps have been set up across the state where food supplies and other required materials have reached, Chief Secretary Karma Gyatso told reporters.
Many villages in the region have been wiped out and the chance of finding survivors was not bright.
After five days of the 6.8 magnitude temblor, stench of bodies buried in the rubble of houses hung heavy in the air. Heavy rains have worsened the situation for rescue workers.
"The pace of the rescue workers is slow due to disrupted road communication and heavy rains. But they are slowly gaining ground," a senior official said.
A five-storey building in Gangtok collapsed and four others adjoining it were also damaged extensively.
At least two persons were trapped under the debris of the collapsed house, which belongs to the state sports secretary, officials said.
The office of United Sikkim floated by football icon Baichung Bhutia was also housed in the building.
"We first escaped to Guma and spent the night there and next morning we started trekking through extremely difficult terrains covered with debris," said Karma Bhutia (30), who arrived in Tung from Lachen after trekking for two days.
Bhutia said several villagers had to crawl some distances in spells since they feared that the wet soil might cave in any moment if they walked on such stretches.
Army sources said 22 engineers and technicians of Poddar Construction, engaged by the Teesta Urja Project, were rescued from Tung, five days after their bus was stranded during the powerful tremor in Sikkim.
"Their bus was halted by a huge boulder and our men rescued them from Tung yesterday. They will be sent to Gangtok today," they said.
15 helicopters of Army and Air Force have been pressed into relief work. For airdropping and reconnaissance, 150 sorties have been carried out so far," an official said.
While nine vital roads, including National Highway 31A and National Highway 55, have been reopened for traffic, two roads Chungthang¿Lachen and Chungthan¿Lachung continued to remain blocked due to landslide.
Rain worsens plight of Sikkim earthquake victims
Soudhriti Bhabani Gangtok, India Today, September 24, 2011: Aggravating the earthquake tragedy that rattled Sikkim on Sunday, two residential highrises in Gangtok collapsed on Friday evening. At least four persons were critically injured in the incident, which occurred amid a downpour around 7.15 pm at Burtuk, two km north of Gangtok."So far, four persons have been evacuated and admitted to the STNM Hospital. The rescue operation is on," Gangtok SSP Prawin Gurung said.
Saying that the heavy rain was slowing down the rescue operation, Gurung added: "A five-storey building has caved in and the building adjacent to it has partially collapsed." Two more buildings in the same row also suffered damage under the impact of the falling structures, he added.
According to reports, at least one woman was trapped inside the second building till late at night even as the rescue work continued.
"The second building was vacant and there is no report of any injury," the police said.
The five-storey building was owned by Karmipi Bhutia, the mentor of former Indian football team captain Baichung Bhutia. The building also housed the offices of Baichung's football academy and an ATM kiosk.
The rescue operations continue in the remote parts of the quake- hit north Sikkim. The state administration officials are apprehensive that the toll figure, which touched the 75-mark on Friday, could inch up further.
Five NDRF teams have been deployed for the search and rescue operations at Shipgyar, Biha, Bringbang Ramam, Lingzya and Dzongu villages in Mangan. Two more NDRF teams, comprising 14 personnel and 16 personnel each, are deployed at Chungthan and Lachung respectively. Altogether, 827 ITBP personnel are engaged in the rescue operations, besides running relief camps for the rescued villagers.
The state government has opened more than 100 relief camps across the tremor-affected areas. Over 2,700 and 550 people have been provided relief and shelter at the army and ITBP camps (at Pengong) respectively.
While 57 persons have died in the north district alone, the toll figure in east, south and west Sikkim is 13, one and four respectively.
Since more than 80 per cent of the buildings in Gangtok have developed severe cracks, the residents have started fleeing the state capital after the aftershocks on Thursday night. "We don't want to stay here anymore.
All the buildings have been built alongside, with hardly any space in between. So if one building collapses, the one next to it is bound to fall down," 34-year-old Tenzing Sherpa, who went downhill with his family and parents on Friday, said.
Thousands of people spent a sleepless Thursday night on the streets of Gangtok after they felt the aftershock, measuring 3.9 on the Richter scale. The collapse of the two highrises has added to the panic already playing on the minds of the people in Gangtok.
Sikkim Chief Minister visits earthquake affected Mangan
Sikkim Mail (http://isikkim.com), Mangan/Gangtok, September 24: Sikkim Chief Minister Pawan Chamling made a visit to the North Sikkim District headquarter of Mangan. Enroute via Dikchu, he made several stops to talk to groups of people gathered who were in need. The first point of visit was the Ringhim Monastery of Mangan which was totally damaged. The Head Lama incharge, Acharya Aptuk Lepcha, made a fervent plea of repair and rehabilitation to the CM. Other people also petitioned the Chief Minister. The Chief Minister promised to rebuild the monastery and requested the area MLA to start the program of rebuilding.
In all his comments to the people the CM was emphatic about clearing all doubts and fears that people were having about the recurrence of another quake of this magnitude. He said that the likelihood of another one coming in a hurry is unlikely though there will be shocks. He also warned that there is danger from landslips and falling boulders as the earth has shaken and boulders have become loose. He also appealed to everyone to help in the process of overcoming this trauma especially those who have lost their loved ones.
He also outlined all the relief measures. He emphasized the need to get the relief immediately to those in need. He said he was empowering all Panchayats and Dzumsas directly and handing over Rs. 5 Lakh to every Panchayat unit and Rs.10 Lakh to each Dzumsa. This will enable them to take immediate action to operate relief and rehabilitation without bureaucratic delay. Furthermore, each Subdivision and BDO will be given Rs. 5 Lakhs and the District Collector Rs. 50 Lakhs. This kind of fund flow will ensure that there is alacrity in providing relief to those in dire need. This he mentioned is being done and it comes at a time when most of the places have already been reached. He further promised to rebuild all the homes of those whose homes had been demolished.
He requested all the MLAs, Panchayats, Pipons and other Government functionaries to work hard and with feeling. He also said that they need to work from their level without waiting for any direction from the top especially when it comes to giving relief to the affected people.
He visited the relief camps which are being run by some local volunteers. He sent out a strong message to the labourers who were there to stay back. He said that there is no reason to fear when the Government was at hand to help them.
The Chief Minister distributed relief directly to the people who were affected and who had assembled there. Those who were unable to reach, their relief cash was left with the District Collector. The Chief Minister was accompanied by the Minister for Roads and Bridges, R. B. Subba; the Minister for Health, D. N. Thakarpa, the Minister for Power, Sonam Lepcha and MLA of Mangan Tashi Wangdi Lepcha. Lok Sabha MP, P. D. Rai, was also present along with other dignitaries and party people.
Rumours add to quake-hit Sikkim's woes
Karma Paljor, CNN-IBN: Gangtok: It has been almost a week since a powerful earthquake struck Sikkim. 75 people have died so far. But rumours and false reports of 17 people being buried alive in a tunnel collapsed caused many to panic.
CNN-IBN's team travelled to a hydroelectricity project site in Chungthang and found out if all was well and that the tunnel was intact and workers were unharmed.
Rumours spread thick and fast that hundreds were buried alive inside tunnels soon after the earthquake jolted the Northeast on the September 18.
One rumour said that 17 were dead, 10 were injured and one was still missing at the Teesta 3 Hydroelectric Project, a company that lost the most men last Sunday.
But when CNN-IBN visited the project site, the team found the tunnels to be intact. One tunnel was in fact being used by the army to evacuate people.
Workers here said that the deaths reported took place not there but at another site.
Nature soothes quake-ravaged
ARUNANGSU ROY CHWODHURY, TH, TOONG, September 23, 2011: A rainbow brings cheer to Sikkimese amid pain and sorrow - On Friday morning, the road was cleared up to Toong from Mangan, headquarters of North Sikkim district. Five days after the massive earthquake that struck the region, it came as a big relief to local residents as well as the Army personnel who were engaged in the gargantuan task of clearing the roads.
From Toong, the road bifurcates towards two quake-ravaged destinations, Shipgyre and Chunghthang.
“The real fight starts from here though. What we have done so far will be nothing in comparison to the challenge that lies ahead,” Sanjay Sharma, Commanding Officer of 52 Engineer Regiment of the Army asserted.
The fresh jolt of earthquake late on Thursday has left life here further vulnerable. Just when the residents of North Sikkim district were about to emerge from last Sunday's nightmare to start life afresh, the initiative got paused once again.
Ashok Subba was searching for remnants of his makeshift home at Toong amid rubbles. The house was flattened under tonnes of debris that rolled down the mountain side during the earthquake. One of his relatives was injured.
He suddenly found a packet full of photographs in the wreckage and began showing pictures of his injured relative.
Two girls, Dali Sherpa and Nagpa Diki, were busy loading their belongings on a lorry to shift to a safer place. Dali's mother, Sonu, was waiting for them in Voong Basti under Naga gram panchayat. They have shifted to a rented house here. Sonu was silent throughout. Grief visible in her eyes, she went about making their new home liveable.
Dali, a Class X student, was injured in a massive landslide and still feels pain at the back of her head. Her school closed down after the quake and none knows when it will reopen.
People from Chunghthang, Lachen, Paigong and Lachung continue trekking towards Mangan, braving the treacherous mountain and forest paths to reach to safer places.
Shering, who trekked down from Chunghthang to Toong this morning, said that the Teesta Urja project tunnel is in good shape and he had reached Chungthang by walking through the tunnel.
He went to Chunghthang on Thursday to find his friend who has not communicated since last Sunday.
It started raining while returning to Mangan from Toong. When the rains stopped, a middle-aged woman's happy voice drew my attention. She was calling her son to show the rainbow that had appeared on the horizon.
Maybe it was the first time that a rainbow was visible in North Sikkim after the quake hit the district as it immediately led people to forget all their fear and pain experienced over the past few days and become delighted.
And, needless to say that nature only can do it!
Housing worry daunting as Sikkim limps back to normality
SUSHANTA TALUKDAR, TH, SAMDUNG (SIKKIM), 23 Sept: Ward-wise teams set up for door-to-door assessment of quake damage- Sikkim is limping back to normality barring the worst-hit and inaccessible quake-hit areas. However, for many affected people like Amrita Tewari, who works as a home guard to feed her two children and her unemployed husband, the worry is to find a safe shelter as their houses have been rendered unsafe by the September 18 quake.
In a day or two, Ms. Tewari is likely to get notice from the local panchayat asking her to vacate the damaged house. Construction of a new house is a worry that haunts the woman, who was on route lining duty on Friday in view of Chief Minister P.K. Chamling's visit to Mangan, headquarters of North District.
“Even after cracks showed up in our building, we decided to continue living in the house as we did not want to go to a relief camp. But, I know, once the official notice is served, authorities will not be responsible if my building collapses. I am in a dilemma,” Ms. Tewari told The Hindu as she took a break to have tea in roadside restaurant after the Chief Minister's convoy had crossed the area.
The local MLA of Tumen-Limgi, Ugen T Gyatso Bhutia, assured panchayat members and residents that the State government would provide all help for rehabilitation. About 400 people of his constituency, whose houses were damaged in the September 18 quake, have taken shelter in eight relief camps. The legislator said the government decided to provide dwellings under the Chief Minister's Rural Housing scheme to all those whose houses had been rendered unsafe. Ward-wise teams were formed in each panchayat for a door-to-door assessment of the quake damage and to ascertain the number of houses rendered unsafe. The people had been advised to immediately vacate unsafe houses, he said.
Amid human misery, even the Kanchenjunga appears lifeless
People from Chungthang braved the rocky mountain, dense forest and turbulent river to reach Mangan on Thursday. Photo: Arunangsu Roy Chowdhury
ARUNANGSU ROY CHOWDHURY, TH, MANGAN, September 23, 2011: For the quake-hit people of Chunghthang, it was a long, arduous trek to safety-
The drizzle turned into a heavy shower. It was only 9 a.m. As thick clouds started wrapping themselves around the Himalayan range, fears of more cloudbursts and landslips grew among the hill people. It could make life more vulnerable in the coming days.
Bulldozers were unable to clear the giant rocks that blocked the road leading to Chunghthang from Mangan due to a landslip. Personnel of the General Reserve Engineering Force (GREF) and the Army have been engaged in the gargantuan task of moving the rocks from the road for the last two days.
The road near Tung, located about 15 km from Mangan, was finally cleared on the day for vehicular movement. Chungthang is another 15 km from Tung. After Tung, the road itself has disappeared as it has slid down the steep hill.
People were stranded on both sides of the landslip area — waiting for Army personnel's nod to climb the rocks and cross the site. The moment the permission was granted, people jumped over the rocks.
One among the crowd was climbing the rocks with bare feet. He was coming from the Chungthang-end and hurriedly crossed over the loose boulders to reach the other side and wait for his friends. When asked about the situation in the Chungthang area, he began to cry. “Please don't ask me anything about Chungthang. By the grace of God, I am alive,” he said.
He was Bishnudhari Das — a contract labourer of the Navayuga Engineering Company (NEC) at Chungthang. On the day of the quake, he was present at the project site. He had run for his life after seeing some of his colleagues getting crushed under the collapsed buildings.
Bishnudhari did not even care to put on his shoes for the long trek through dense forests and rocky terrain: “My house was flattened and I had no option but to leave behind all my belongings. I just ran for my life.”
Another NEC worker, Bikas, was seen struggling to trek along with his wife Nirmala and their four-year-old son. They spent two sleepless nights under the open sky since Sunday before finally mustering the courage for the long, arduous trek.
“We had to cross a turbulent river by holding on to a rope. The forest path was full of leeches. We just want to reach home safely,” Nirmala said fighting back her tears.
Kuldeep Singh, a Subedar of the GREF, narrated the tale of 22 lucky passengers of an ill-fated bus that remained stuck under rubble for two days before the passengers were rescued.
Life is very precious here. When I opened my hotel window at Mangan on Thursday morning, the majestic view of the Kanchenjunga's snowy peak mesmerised me. But the day's traumatic experiences have taught me that nothing can be more beautiful than life itself — even the Kanchenjunga appears lifeless amid such human misery.
Buildings flout seismic norms
Prithvijit Mitra, TNN | Sep 24, 2011:KOLKATA: Even as the Geological Survey of India (GSI) is contemplating an advisory for Kolkata, structural experts have warned that basic construction norms prescribed by the Bureau of Indian Standards (BIS) were being rampantly flouted in the city.
Structures, they pointed out, were being erected without a frequency study of the site and buildings, while beams, bricks, steel and other reinforcements used were not being made strong enough to withstand tremors. It could be risky in the long-run, they said.
The Sikkim earthquake on Sunday made several tall structures in Kolkata sway. Some even developed cracks following the tremor. GSI scientists pointed out that soft floors or vacant ground floors reserved for car parking could be responsible for the damages since they allow shock waves to travel freely, hitting the pillars with a great intensity. "While this could be technically correct, it should also be considered that car parks are permitted in seismic resistant building designs approved by the BIS. If you go by standard 1893 - the BSI code for structures - car parks are safe provided the other norms are adhered to. Unfortunately, this is not happening in most structures that are mushrooming across the city," said Anjan Datta, structural expert.
Standard 1893 lays down a seismic frequency chart that requires a measurement of response frequency and peak ground acceleration of structures in case of a tremor. It also recommends a particular thickness and density for column and beam junctions in high-rises. They should be ductile enough to absorb shocks, it says. "While bigger projects stick to the norms, they are few in number. There is no vigil on the innumerable smaller buildings that are coming up everywhere. A look at the structures makes it clear that they have bypassed the safety rules," added Datta. Buildings in Howrah, for instance, were guilty of flouting norms most blatantly, Datta said.
According to standard 1893, 550D-grade steel has to be used in buildings. These are shock-absorbent and ductile. Brick walls must be rejected in favour of reinforced concrete walls. "In case a brick wall is used, there should be hybrid netting in every third layer. This is because the mortar used between the bricks can't withstand a severe shock. There is none to check if these are being done," said Datta.
The GSI has prepared an advisory on the basis of data collected on Kolkata's underground composition from various sources. It suggests the exclusion of soft floors and recommends adequate distance between buildings other than making them conventional, symmetrical and solid structures, sans fancy frills. No seismic zonation study, however, has yet been done to assess the city's vulnerability to quakes. "There are numerous buildings which don't stick to these basic rules. So far as the walls and beams are concerned, there has to be a stricter vigilance. It can happen only if we have an advisory for the city. We are planning to take it up with the BSI," said a GSI official.
Dragon's threat makes quake-hit Sikkim suffer
Jayanta Gupta, TNN, Sep 24, 2011: KOLKATA: Nearly a week after the September 18 earthquake in Sikkim, relief hasn't yet reached the interior areas of this tiny state. Reason: The state lacks infrastructure, particularly roads and airfields, which would have speeded up succour to the people of the state.
Advanced landing grounds and roads had not been developed as mandarins in Delhi feared such infrastructure would help the Chinese over-run the region in the event of a repetition of the 1962 border conflict.
The Air Force is still finding it difficult to move men and equipment to the worstaffected areas. Eastern Air Command sources said mobilization would have been faster had the IAF managed to land AN-32 or a similar large transport aircraft close to Mangan, Chungthang or Lachung.
"Delhi woke up from its slumber only recently to realize that infrastructure development is required in the northeast. This shift from its Pakistan-centric approach has led to development of facilities in Assam and Arunachal Pradesh. It may take some more time for infrastructure to be built in north or east Sikkim," said a state government source.
The Union defence ministry was able to successfully reason that Sikkim should be left underdeveloped for "strategic" purposes. The fear was if China were to carry out a lightning strike across the Line of Actual Control (LAC) in north Sikkim, it would be able to take the entire state by using the infrastructure built by the Union or the state government.
"The philosophy was that should such a strike take place and Indian forces be compelled to fall back, the Chinese should not get access to infrastructure that would help consolidate its position," said the official.
"In reality, this was a ridiculous strategy. China is rapidly building infrastructure on the Tibet side and lack of infrastructure on our side won't deter them. It is a matter of concern that no ALGs exist in Sikkim," said another official.
The Army is now considering a Mountain Strike Corps and may station ultralight howitzers and light tanks along the LAC. Now, IAF might also consider ALGs in north and east Sikkim.
A detailed report on the earthquake (M:6.8) of 18thSeptember, 2011 in Sikkim-Nepal border region
An earthquake of magnitude 6.8 occurred on 18th September at 18:11 hrs IST in
Sikkim-Nepal Border region. The preliminary hypo-central parameters of this earthquake, as estimated by the Seismic Monitoring Network of India Meteorological Department (IMD) are given below:
Date of occurrence : 18/09/2011
Time : 18:11 hrs (IST)
Magnitude : 6.8
Focal depth : 10 Km
Epiecentre
Latitude & Longitude : 27.7o N & 88.2o E
Region : Sikkim-Nepal Border region.
The event, which comes under the category of “Moderate earthquake”, was also reported widely felt in Sikkim, Assam, Meghalaya, northern parts of West Bengal, Bihar, parts of other eastern and northern regions of India. The epicentre lies in a seismically known and active belt called, Alpide-Himalayan seismic belt. The location of the earthquake is shown on the seismicity map of Sikkim and neighbouring areas given at Annexure-1. The main shock was followed by several aftershocks of low intensity and a few significant aftershocks (M≥4.0) located by the network, as detailed below. It may, however, be mentioned that the magnitude and frequency of aftershocks will reduce with the passage of time.
S.No. Date Time of aftershocks
Hr:Min (In IST)
Magnitude
1. 18.09.2011 18 :42 5.0
2. 18.09.2011 19:24 4.5
3. 19.09.2011 03:22 4.2
The earthquake source parameters have been disseminated to all concerned state and
central government agencies related with initiating relief and rescue operations in the region.
The information is also put on IMD‟s website for public use. The aftershock activity is being continuously monitored and information on significant aftershocks is being transmitted to all the concerned agencies.
The source parameters of the event are estimated using data of a total of 77 seismic stations in India and across the globe spread more or less in all azimuths (Annexure-2). The details of various magnitude estimates are given in Annexure-3. The preliminary faulting mechanism of the subject earthquake, as estimated through Centroid Moment Tensor (CMT) and Moment Tensor (MT) solutions are given in (Annexure- 4 & -5). The faulting mechanism indicates reverse faulting associated with the tectonic processes related to the collision of Indian and Eurasian plates along the major thrusts in the region.
The centroid moment depth indicated by the CMT solution (10 km.) for the present event matches well with the hypo-central estimates. The CMT and MT solutions are obtained from waveform modelling making use of Body and Surface waves respectively. The process essentially involves in simulating the synthetic seismograms by assuming a known source, path and instrumental characteristics. These synthetic seismograms are then matched with the observed ones at various stations in an attempt to arrive at the characteristics of the source, which produces the best synthetic seismograms matching with the observed ones.
2. A slight magnitude earthquake (M:3.9) also occurred at 06 hours 22 minutes IST on 19th September, 2011 in the Latur district of Maharashtra. This event is located about 1500 kms away from the epicenter of the earthquake in Sikkim-Nepal border region of 18th September, 2011 and hence felt not directly related to it.
3. Strong Motion Accelerographs (SMAs), meant for recording strong ground vibrations of the kind experienced during the subject event, are deployed by academic institutions, viz., IIT (Roorkee), IIT (Kharagpur), etc. in the Himalayan region including northeast India through sponsored projects supported by MoES. These data sets would provide valuable information for designing earthquake resistant structures in the region in future.
4. Past seismicity of the region:
Historical and instrumentally recorded data on earthquakes show that the Sikkim and adjoining area lies in a region prone to be affected by moderate to great earthquakes in the past. Some noteworthy earthquakes that have affected the region are:
(i) Cachar earthquake of 10.01.1869 (M: 7.5),
(ii) Shillong plateau earthquake of 12.06.1897 (M: 8.7),
(iii) Dhubri earthquake of 02.07.1930 (M: 7.1),
(iv) Bihar-Nepal Border earthquake of 15.01.1934 (M: 8.3),
(v) Arunachal Pradesh – China Border earthquake of 15.08.1950 (M: 8.5),
(vi) Nepal-India Border earthquake of 21.08.1988 (M: 6.4)
(vii) Sikkim earthquake of 14.02.2006 (M: 5.7)
(viii) Bhutan earthquake of 21.09.2009 (M:6.2)
The Sikkim and adjoining region is known to be part of the seismically active region of the, Alpide-Himalayan global seismic belt‟, with four great earthquakes of the world of magnitude 8.0 and above occurring in this region. The occurrence of earthquakes in the region is broadly associated with the tectonic activity along well known faults in the Himalayas, namely, Main Boundary Thrust (MBT), Main Central Thrust (MCT). Other
prominent geological / tectonic features in and around Sikkim include: Tista lineament,
Kunchenjunga lineament, Purnea-Everest lineament, Arun lineament and Dhubri fault in the southeast.
In the seismic zoning map of India prepared under the auspices of Bureau of Indian Standards (BIS code IS: 1893: Part I 2002), by a committee of experts representing various scientific institutions including India Meteorological Department (IMD), the entire area of Sikkim lies in Zone IV. The seismic Zone IV is broadly associated with seismic intensity VIII on the Modified Mercalli Intensity (MMI) scale. It may be mentioned that the seismic intensity VIII on MMI scale corresponds to a horizontal ground acceleration range of 51-350 cm / sec 2
or an average acceleration of 172 cm / sec 2
in any direction. The ground acceleration and hence the intensity of an earthquake at a place depends on magnitude of earthquake, distance from the focus, duration of earthquake, type of underlying soil and its damping characteristics and liquefaction potential. The damage to the buildings founded on soft soil or filled up earth is higher than that in the similar type of buildings having their foundation on hard bedrock. Also, the damage will be higher for higher magnitude and long duration earthquakes, less epicentral distance soft soil conditions and areas with high liquefaction potential.
Presently, there is no scientific technique available anywhere in the world to predict occurrence of earthquakes with reasonable degree of accuracy with regard to space, time and magnitude. It is, therefore suggested that appropriate steps may be taken to ensure that the dwellings and other structures in the region are designed and constructed as per guidelines laid down by Bureau of Indian Standards (BIS) to minimize the losses caused by earthquakes.
The choice of seismic factor to be adopted for designing and engineering the structures depends on horizontal ground acceleration and various other factors including type of structures, the ground conditions and also importance of structures. For important and critical structures, site specific spectral studies have to be carried out before assessing the seismic design parameters. Suitable seismic design parameters may be adopted as per recommendations of National Committee on Seismic Design Parameters (NCSDP) for designing and engineering Hydroelectric Projects.
5. Causes of earthquakes:
Earthquakes are the result of a process, wherein the underground rocks suddenly
break, along a plane of weakness called „fault’, when the prevalent stresses exceed the elastic strength of the rock. The buildup of stresses and subsequent release of the strain energy in the form of earthquakes is a continuous process, which keeps repeating in geological time scale.
A number of theoretical assumptions that explain the forces, which cause accumulation of stresses inside the earth include: drifting of continents and mountain building process, shortening of Earth‟s Crust due to cooling and contraction, disturbance of mass distribution on the Earth‟s surface as a result of erosion of high lands and deposition of sediments in the sea and generation of heat by radioactive material inside the Earth‟s Crust.
6. Classification of earthquakes:
Based on magnitude (M), earthquakes may be classified as Micro- (M<3.0), Slight- (M:3.0 -4.9), Moderate- (M:5.0-6.9), Great- (M:7.0-8.0) and Very great- (M>8.0).
Earthquakes may also be classified as shallow-focus, intermediate-focus and deep-focus depending upon their focal depths. Shallow-focus earthquakes, which constitute about 80% of total energy release on the globe, have their foci at a depth between 0 and 70 km. and occur along collision and subduction zones, oceanic ridges and transform faults.
Intermediate-focus earthquakes (focal depth between 71 and 300 km.) and deep-focus
earthquakes (focal depth greater than 300 km.) occur in subduction zones, such as AndamanNicobar island region and northeast India. Most earthquakes originate within the crust and beneath the Moho, the number falls abruptly and dies down to zero at a depth of about 700 km. On an average, it is expected that about two earthquakes of M~8.0, ~20 earthquakes of M~7.0, ~100 earthquakes of M~6.0 and ~3000 earthquakes of M~5.0 are likely to occur every year over the globe. A list of significant earthquakes in the recent past in and around India is given below:
Uttarkashi earthquake of October 20, 1991 (M: 6.6).
Latur earthquake of September 30, 1993 (M: 6.3).
Jabalpur earthquake of May 22, 1997 (M: 6.0).
Chamoli earthquake of March 29, 1999 (M: 6.8).
Bhuj earthquake of January 26, 2001 (M: 7.7).
Sumatra earthquake of December 26, 2004 (Mw:9.3)
Muzaffarabad earthquake of October 8, 2005 (Ms:7.6)
7. Seismic Zoning of India:
Bureau of Indian Standards [IS-1893 (Part-1): 2002], based on various scientific inputs
collected from a number of agencies, has grouped the country into four seismic zones, viz.
Zone-II, -III, -IV and –V. Of these, Zone V is seismically the most prone region, while zone
II is the least. The Modified Mercalli (MM) intensity, which measures the impact of the
earthquakes on the surface of the earth, broadly associated with various zones is as follows:
Seismic Zone MM Intensity
II (Low intensity zone) VI (or less)
III (Moderate intensity zone) VII
IV (Severe intensity zone) VIII
V (Very severe intensity zone) IX (and above)
Broadly, Zone-V (12% of land) comprises of entire northeastern India, parts of Jammu
and Kashmir, Himachal Pradesh, Uttarakhand, Rann of Kutch in Gujarat, parts of North
Bihar and Andaman & Nicobar islands. Zone-IV (18%) covers remaining parts of Jammu & Kashmir and Himachal Pradesh, Union Territory of Delhi, Sikkim, northern parts of Uttar Pradesh, Bihar and West Bengal, parts of Gujarat and some portion of Maharashtra near the west coast and Rajasthan. Zone-III (27%) comprises of Kerala, Goa, Lakshadweep islands, remaining parts of Uttar Pradesh, Gujarat and West Bengal, parts of Punjab, Rajasthan, Madhya Pradesh, Bihar, Jharkhand, Chhatisgarh, Maharashtra, Orissa, Andhra Pradesh, Tamilnadu and Karnataka. Zone-II (43%) covers remaining parts of the country.
8. Seismic Hazard and Risk Microzonation:
Microzonation is the process of dividing a geographic domain into small units of likely uniform hazard level and nature. This classification is done based on Geoscientific, Geotechnical, Seismological and Engineering seismological parameters. The Hazard micro zone map is transformed into seismic risk microzonation map with inputs on Vulnerability of Built environment and Anthropological / Sociological inputs. As earthquake prediction is not possible precisely in time and space, seismic Hazard microzonation provides an important tool for generating parameters for site specific structural designing, land use planning and disaster mitigation. Seismic microzonation studies have been completed for Delhi (1:50,000 scale), Guwahati (1:25,000 scale), Sikkim (1:25,000 scale) and Bangalore city (1:25,000 scale).
Microzonation map for NCT of Delhi is further being refined at 1:10,000 scale. It is planned to take up microzonation studies for all State Capitals and cities with a population density of half a million lying in Zones III, IV and V. The work will be taken up in phased manner and 30 cities have been indentified to start with. In this connection, detailed guidelines have been prepared for standardization of procedures / methods for adoption taking up these studies.
9. Disaster mitigation:
Loss of lives during an earthquake is mostly due to damage or collapse of houses/ structures.
However, any structure can bear the vibration from an earthquake if it has enough strength and sturdiness. Bureau of Indian Standards (BIS) has published criterion for construction of earthquake resistant structures. The design of structure should be such that the whole structure behaves as one unit at the time of vibration rather than assemblage of parts.
Important structures like hospitals, fire stations etc. should be made earthquake resistant.
However, it is not economical to demolish and reconstruct most of the poorly built structures; for such poorly built structures BIS has prepared guidelines for their retrofitting. In addition to this, HUDCO & BMTPC have also published guidelines and brochures for construction and retrofitting of buildings. Further, losses due to earthquakes can be considerably reduced through proper planning and implementation of pre- and post-disaster preparedness and management strategies by respective state government agencies by working out the possible earthquake effects for various seismic zones.
10. National Program on Earthquake Precursors (NPEP)
It is now recognized that earthquake generation processes are so complex and site specific that often, no two different tectonic environments behave in similar manner in terms of providing clues about the ongoing physical processes in the earthquake source region. It is, thus, necessary to adopt an integrated approach of generation, assimilation and analyses of a variety of earthquake precursory phenomena in critical seismotectonic environments in the country in a comprehensive manner. Towards meeting this objective, a National Program on Earthquake Precursors (NPEP) has been initiated recently by MoES through a multiinstitutional and multi-disciplinary mechanism.
As part of this, a suite of Multi-Parametric Geophysical Observatories (MPGOs) have been set up at Ghuttu, Shillong and Koyna to monitor various earthquake precursory phenomenon such as, seismicity patterns, crustal deformations, gravity anomalies, electrical resistivity changes, electromagnetic perturbations, water level changes, geo-hydrochemical changes, Radon and Helium anomalies and thermal anomalies, etc. Preliminary analyses of these data sets have provided useful leads on the ongoing tectonic processes in the Koyna-Warna region. It is proposed to intensity these investigations during the XII FYP.
11. Deep drilling program in Koyna region
The Koyna Dam located in Maharashtra, western India is the most outstanding example of Reservoir Triggered Seismicity (RTS), where triggered earthquakes have been occurring in a restricted area of 20x30 sq km since the impoundment of Shivajisagar Lake in 1962. These include the largest triggered earthquake of M~6.3 on Dec 10 1967, 22 earthquakes of M>5, about 200 earthquakes of M~4, and several thousand smaller earthquakes since 1962.
Considering the importance of deep borehole investigations, it is proposed to undertake a suite of observations in deep borehole(s) in the Koyna area. The work will be carried out in collaboration with ICDP and the observations will include stress regime, pore fluid pressure and its variations, heat flow and its variation, orientation of faults, study of chemical properties of fluids, before, during and after earthquake. The proposed investigations through the borehole will facilitate i) observation and analysis of data, generated through the operation of borehole for 4-5 year of time, when it is anticipated that a few earthquakes of magnitude ~3 would occur in the immediate vicinity of borehole, ii) continuous observation to study the data in the far and near field of the earthquake and temporal variation w.r.t. occurrence of earthquake and iii) development of a model of RTS mechanism.
12. The critical structures viz., nuclear power plants and dams in the country are designed taking into consideration the past seismicity and the expected ground motions in the region, estimated through a detailed site specific analysis using probabilistic and deterministic approaches carried out by earthquake engineering community.13. Efforts are being made to improve the understanding of earthquake processes and their impacts towards better management and mitigation of the effects of earthquakes in future. A document detailing the proposals planned to be taken up during the XII FYP is attached for kind information.
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