The 1950 Assam–Tibet earthquake, also known as the Assam earthquake, occurred on 15 August and had a moment magnitude of 8.6. The epicentre was located in the Mishmi Hills, known in Chinese as the Qilinggong Mountains (祁灵公山), south of the Kangri Garpo and just east of the Himalayas in the North-East Frontier Agency part of Assam, India. This area, south of the McMahon Line and now known as Arunachal Pradesh, is today disputed between China and India. The earthquake was destructive in both Assam (India) and Tibet (China), and approximately 4,800 people were killed. The earthquake is notable as being the largest recorded quake caused by continental collision rather than subduction, and is also notable for the loud noises produced by the quake and reported throughout the region.
In an attempt to further uncover the seismic history of Northeast India, field studies were conducted by scientists with the National Geophysical Research Institute and Institute of Physics, Bhubaneswar. The study discovered signs of soil liquefaction including sills and sand volcanoes inside of at least twelve trenches in alluvial fans and on the Burhi Dihing River Valley that were formed by past seismic activity. Radiocarbon dating identified the deposits at roughly 500 years old, which would correspond with a recorded earthquake in 1548.
The earthquake occurred in the rugged mountainous areas between the Himalayas and the Hengduan Mountains. The earthquake was located just south of the McMahon Line between India and Tibet, and had devastating effects in both regions. Today this area is claimed as part of Zayü and Mêdog Counties in the Tibet Autonomous Region by China, and as part of Lohit District in Arunachal Pradesh by India. This great earthquake has a calculated magnitude of 8.6 and is regarded as one of the most important since the introduction of seismological observing stations.
It was the sixth largest earthquake of the 20th century. It is also the largest known earthquake to have not been caused by an oceanic subduction. Instead, this quake was caused by two continental plates colliding.
Aftershocks were numerous; many of them were of magnitude 6 and over and well enough recorded at distant stations for reasonably good epicentre location. From such data, the Indian Seismological Service, established an enormous geographical spread of this activity, from about 90 deg to 97 deg east longitude, with the epicentre of the great earthquake near the eastern margin.
The 1950 Assam–Tibet earthquake had devastating effects on both Assam and Tibet. In Assam, 1,526 fatalities were recorded and another 3,300 were reported in Tibet for a total of approximately 4,800 deaths.
Alterations of relief were brought about by many rock falls in the Mishmi Hills and surrounding forested regions. In the Arbor Hills, 70 villages were destroyed with 156 casualties due to landslides. Landslides blocked the tributaries of the Brahmaputra. In the Dibang Valley, a landslide lake burst without causing damage, but another at Subansiri River opened after an interval of 8 days and the wave, 7 m (23 ft) high, submerged several villages and killed 532 people.
The shock was more damaging in Assam, in terms of property loss, than the earthquake of 1897. In addition to the extreme shaking, there were floods when the rivers rose high after the earthquake bringing down sand, mud, trees, and all kinds of debris. Pilots flying over the meizoseismal area reported great changes in topography. This was largely due to enormous landslides, some of which were photographed.
In Tibet, Heinrich Harrer reported strong shaking in Lhasa and loud cracking noises from the earth. Aftershocks were felt in Lhasa for days. In Rima, Tibet (modern-day Zayü Town), Frank Kingdon-Ward, noted violent shaking, extensive slides, and the rise of the streams. Helen Myers Morse, an American missionary living in Putao, northern Burma at the time, wrote letters home describing the main shake, the numerous aftershocks, and of the noise coming out of the earth.
One of the more westerly aftershocks, a few days later, was felt more extensively in Assam than the main shock. This led certain journalists to the believe that the later shock was 'bigger' and must be the greatest earthquake of all time. This is a typical example of the confusion between the essential concepts of magnitude and intensity. The extraordinary sounds heard by Kingdon-Ward and many others at the times of the main earthquake have been specially investigated. Seiches were observed as far away as Norway and England. (p. 63-64.)
An article in Science, published in response to the 2001 Bhuj earthquake, calculated that 70 percent of the Himalayas could experience an extremely powerful earthquake. The prediction came from research of the historical records from the area as well as the presumption that since the 1950 Medog earthquake enough slippage has taken place for a large earthquake to occur. In 2015, the Himalayas were hit by another large earthquake with an epicenter further west in Nepal.
Earthquakes in China
- ^ abcdISC (2015), ISC-GEM Global Instrumental Earthquake Catalogue (1900–2009), Version 2.0, International Seismological Centre
- ^USGS. "M8.6 - eastern Xizang-India border region". United States Geological Survey.
- ^ ab"Historic Earthquakes, Assam - Tibet". United States Geological Survey. Archived from the original on November 10, 2016. Retrieved January 24, 2012.
- ^Reddy, D.V.; Nagabhushanam, P.; et al. (September 2009). "The great 1950 Assam Earthquake revisited: Field evidences of liquefaction and search for paleoseismic events". Tectonophysics. 474 (3): 463–472. Bibcode:2009Tectp.474..463R. doi:10.1016/j.tecto.2009.04.024.
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- ^"8·15墨脱地震". Baidu. Baidu. Retrieved 19 September 2017.
- ^Harrer, Heinrich (1953). Seven Years in Tibet. Putnam.
- ^Myers Morse, Helen (2003). Once I Was Young. Terre Haute, Indiana. pp. 167–171.
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The 2001 Gujarat earthquake, also known as the Bhuj earthquake, occurred on 26 January, India's 51st Republic Day, at 08:46 AM IST and lasted for over 2 minutes. The epicentre was about 9 km south-southwest of the village of Chobari in BhachauTaluka of Kutch District of Gujarat, India.
The intraplate earthquake reached 7.7 on the moment magnitude scale and had a maximum felt intensity of X (Extreme) on the Mercalli intensity scale. The earthquake killed between 13,805 and 20,023 people (including 18 in southeastern Pakistan), injured another 167,000 and destroyed nearly 400,000 homes.
See also: Geology of India
Gujarat lies 300–400 km from the plate boundary between the Indian Plate and the Eurasian Plate, but the current tectonics are still governed by the effects of the continuing continental collision along this boundary. During the break-up of Gondwana in the Jurassic, this area was affected by rifting with a roughly west-east trend. During the collision with Eurasia the area has undergone shortening, involving both reactivation of the original rift faults and development of new low-angle thrust faults. The related folding has formed a series of ranges, particularly in central Kutch.
The focal mechanism of most earthquakes is consistent with reverse faulting on reactivated rift faults. The pattern of uplift and subsidence associated with the 1819 Rann of Kutch earthquake is consistent with reactivation of such a fault.
The 2001 Gujarat earthquake was caused by movement on a previously unknown south-dipping fault, trending parallel to the inferred rift structures.
The death toll in the Kutch region was 12,300. Bhuj, which was situated only 20 km away from the epicentre, was devastated. Considerable damage also occurred in Bhachau and Anjar with hundreds of villages flattened in Taluka of Anjar, Bhuj and Bhachau. Over a million structures were damaged or destroyed, including many historic buildings and tourist attractions. The quake destroyed around 40% of homes, eight schools, two hospitals and 4 km of road in Bhuj, and partly destroyed the city's historic Swaminarayan temple and historic fort as well Prag Mahal and Aina Mahal. The Indian National Trust for Arts and Cultural Heritage (INTACH) inspected more than 250 heritage buildings in Kutch and Saurashtra and found that about 40% of them are either collapsed or seriously damaged. Only 10% were undamaged.
In Ahmedabad, Gujarat's commercial capital with a population of 6.4 million, as many as 50 multi-storey buildings collapsed and several hundred people were killed. Total property damage was estimated at $7.5 billion. In Kutch, the earthquake destroyed about 60% of food and water supplies and around 258,000 houses, 90% of the district's housing stock. The biggest setback was the total demolition of the Bhuj Civil hospital. The Indian military provided emergency support which was later augmented by the International Federation of Red Cross and Red Crescent Society. A temporary Red Cross hospital remained in Bhuj to provide care while a replacement hospital was built.
Four months after the earthquake the Gujarat government announced the Gujarat Earthquake Reconstruction and Rehabilitation Policy. The policy proposed a different approach to urban and rural construction with the estimated cost of rebuilding to be US$1.77 billion.
The main objectives of the policy included repairing, building, and strengthening houses and public buildings. Other objectives included the revival of the economy, health support, and reconstruction of the community and social infrastructure.
The housing policy focused on the removal of rubble, setting up temporary shelters, full reconstruction of damaged houses, and the retrofitting of undamaged units. The policy established a community-driven housing recovery process. The communities affected by the earthquake were given the option for complete or partial relocation to in-situ reconstruction. The total number of eligible houses to be repaired was 929,682 and the total number of eligible houses to be reconstructed was 213,685. By 2003, 882,896 (94%) houses were repaired and 113,271 (53%) were reconstructed.
The Environmental Planning Collaborative (EPC) was commissioned to provide a new city plan for the city of Bhuj. The plan focused on creating a wider roadway network to provide emergency access to the city. The EPC used land readjustment (LR) in the form of eight town planning schemes. This was implemented by deducting land from private lot sizes to create adequate public land for the widening of roadways. The remaining land was readjusted and given back to the original owners as final plots.
In order to support the reconstruction and rehabilitation of the city, the Government of Gujarat created four assistance packages worth up to US$1 billion. These packages assisted about 300,000 families. The government also announced a US$2.5 million package to revive small, medium, and cottage industries. The World Bank and the Asian Development Bank also provided loans worth $300 million and $500 million respectively.
Assistance was received from many countries and organisations.
|Bangladesh||20,000 tons of rice and a 12-member medical team|
|Greece||US$270,000 in financial aid relief supplies|
|Israel||150 member emergency aid mission|
|Italy||US$2.3 million for emergency equipment|
|The Netherlands||US$2.5 million through UNICEF|
|New Zealand||US$200,000 grant|
|Pakistan||13 tons of relief material such as blankets and food|
|Syria||Medical and other relief supplies|
|United Kingdom||£10 million|
|United States||Relief supplies up to US$5 million|
|UAE, Vietnam, Saudi Arabia||Relief material and supplies|
Smritivan, a memorial park and museum dedicated to victims of the earthquake was built on top of Bhujia Hill. 13,823 trees, each dedicated to a victim, were planted in the garden and 108 small water reservoirs were created on the hill.
- ^M7.7 Bhuj " Republic Day " Earthquake, 2001
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- ^Maurya, D. M.; Chowksey, Vikas; Patidar, A. K.; Chamyal, L. S. (2017). "A review and new data on neotectonic evolution of active faults in the Kachchh Basin, Western India: legacy of post-Deccan Trap tectonic inversion". Geological Society, London, Special Publications. 445 (1): 237–268. Bibcode:2017GSLSP.445..237M. doi:10.1144/sp445.7.
- ^Bodin, P.; Horton S. (2004). "Source Parameters and Tectonic Implications of Aftershocks of the Mw 7.6 Bhuj Earthquake of 26 January 2001"(PDF). Bulletin of the Seismological Society of America. Seismological Society of America. 94 (3): 818–827. Bibcode:2004BuSSA..94..818B. doi:10.1785/0120030176. Retrieved 2 April 2012.
- ^Li, Qingsong; Liu, Mian; Yang, Youqing (17 March 2013). "The 01/26/2001 Bhuj, India, Earthquake: Intraplate or Interplate?". Plate Boundary Zones. American Geophysical Union. pp. 255–264. doi:10.1029/gd030p0255. ISBN 978-1-118-67044-6. ISSN 2329-1540.
- ^Interdisciplinary Observations on The January 2001 Bhuj, Gujarat Earthquake
- ^Rabindra, Vasavada; Edmund, Booth (2001). "Effect of the Bhuj, India earthquake of 26 January 2001 on heritage buildings". Beiträge zur Allgemeinen und Vergleichenden Archäologie. 21. ISSN 0170-9518.
- ^Eidinger, John M. (2001-01-01). Gujarat (Kutch), India, M7.7 Earthquake of January 26, 2001, and Napa M5.2 Earthquake of September 3, 2000. ASCE Publications. ISBN 9780784475065.
- ^ abJha, Abhas K. (2010-01-15). Safer Homes, Stronger Communities: A Handbook for Reconstructing after Natural Disasters. World Bank Publications. ISBN 9780821382684.
- ^Jha, Abhas K. (2010-01-15). Safer Homes, Stronger Communities: A Handbook for Reconstructing after Natural Disasters. World Bank Publications. ISBN 9780821382684.
- ^ abcdSinha, Anil (2003). "The Gujarat Earthquake 2001"(PDF). Asian Disaster Reduction Center. Asian Disaster Reduction Center. Retrieved 20 July 2016.
- ^ abcByahut, Sweta (Fall 2014). "Post-Earthquake Reconstruction Planning Using Land Readjustment in Bhuj (India)". Journal of the American Planning Association. 80 (4): 440. doi:10.1080/01944363.2014.989132 – via Academic Search Complete.
- ^Byahut, Sweta; Mittal, Jay (2016). "Using Land Readjustment in Rebuilding the Earthquake-Damaged City of Bhuj, India". Journal of Urban Planning and Development. 143: 05016012. doi:10.1061/(ASCE)UP.1943-5444.0000354.