| 项目编号: | NE/K016474/1
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| 项目名称: | Coseismic deformation associated with the 11th November 2012 Shwebo earthquake, Myanmar |
| 作者: | Ian Mark Watkinson
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| 承担单位: | Royal Holloway, University of London
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| 批准年: | 2012
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| 开始日期: | 2013-11-02
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| 结束日期: | 2013-10-07
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| 资助金额: | GBP12324
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| 资助来源: | UK-NERC
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| 项目类别: | Research Grant
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| 国家: | UK
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| 语种: | 英语
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| 特色学科分类: | Archaeology 
; (10%)
; Area Studies 
; (10%)
; Development studies 
; (10%)
; Geosciences 
; (70%)
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| 英文摘要: | Earthquakes occur when blocks of the Earth's crust slide past east other along fractures called tectonic faults. Motion between crustal blocks is a result of tectonic processes such as formation of new oceanic crust at mid-ocean ridges, sinking of old crust into the interior of the Earth at subduction zones and collision between continental plates.
Friction and normal stresses across faults cause them to be inactive, or 'locked' most of the time. Motion between crustal fragments is accommodated by elastic bending of rocks either side of the locked fault. When the stress parallel to the fault becomes sufficient to overcome friction and normal stresses, the fault slips rapidly. Seismic waves are a result of this sudden release of elastic energy. They radiate through the crust and spread around the Earth in a matter of minutes. The magnitude of an earthquake is related to the length of the fault rupture, and the amount of elastic bending since the previous earthquake.
Today the Indian plate is moving north relative to Eurasia, accompanied by widespread seismicity. The Himalayan mountains are an expression of the convergence between these two continental plates since 50 million years ago. Along its eastern margin the Indian plate is sliding sideways past Indochina. More than half the annual motion across this sideways, or 'transform', plate boundary is focussed on the 1500 km-long Sagaing Fault in Myanmar.
Since 1918 there have been 6 major earthquakes (magnitude 7.0 to 7.9) along the Sagaing Fault. They were unequally distributed along the length of the fault, and a 260 km-long section remains un-ruptured. It is likely that this section is locked and may fail in a single large earthquake in the near future. The capital city of Myanmar, Nay Pyi Taw, straddles the Sagaing Fault in the centre of the un-ruptured section.
On 11/11/12, a magnitude 6.8 earthquake ruptured the Sagaing Fault at Shwebo, near Mandalay. The earthquake focus was at a shallow depth of about 10 km. Sixteen people were killed and fifty-two injured by the earthquake. Hundreds of houses, schools and religious buildings were damaged along a 150 km section of the Sagaing Fault. Aftershocks still continue.
The ultimate aim of this project is to mathematically model the state of stress along the Sagaing Fault. Stress modelling highlights where the fault is relaxed, and where stress is elevated. Earthquakes nucleate in areas of elevated stress. Data about previous earthquake ruptures is required to model the stress pattern along the fault. The 11th November Shwebo earthquake is the first large earthquake since Myanmar became accessible to foreign researchers, and offers an unprecedented opportunity to collect such data directly from the field.
During an earthquake like the Shwebo event, the sides of the fault will slide about 0.2-1 m past each other. This displacement will cause a surface rupture, with sideways and vertical displacements. Systematic mapping of the surface rupture quantifies the amount and direction of slip along the fault, and shows whether the fault at depth is a single fracture or more segmented. Mapping the terminations of the fault rupture gives important information about how rupture is arrested. For example, ruptures often terminate across large gaps in the main fault where there is subsidence.
This research will use surface rupture data collected within 3 months of the Shwebo earthquake to understand how rupture propagates along the Sagaing Fault, and to find where future earthquakes are likely, with particular attention to the fault immediately south of Mandalay, where a long section has conspicuously little historical seismicity. The research will be a collaboration between experts in structural geology, seismology and seismic hazard assessment in Europe and Myanmar. The results will be widely communicated so they may be used to inform development policy in Myanmar and other seismically active areas. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/102335
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| Appears in Collections: | 科学计划与规划
气候变化与战略
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作者单位: | Royal Holloway, University of London
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| Recommended Citation: | |
Ian Mark Watkinson. Coseismic deformation associated with the 11th November 2012 Shwebo earthquake, Myanmar. 2012-01-01.
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