Surface rupture in the 12 May 2008 Sichuan earthquake

2008 年 5 月 12 日四川地震中的地表破裂

• 批准号: NE/G002665/1
• 负责人: Alexander Densmore
• 金额: $ 2.48万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG002665%2F1
• 关键词: Surface; rupture; 12; May; 2008

The 12 May 2008 earthquake in Sichuan Province, China, had a magnitude of 7.9 and devastated a large area of western China. The earthquake occurred beneath some of the steepest and most rugged mountains in the world, the Longmen Shan or Dragon's Gate Mountains. This range, steeper than the Himalaya, forms the eastern edge of the Tibetan Plateau, the 5 km high collision zone between India and Eurasia. The origin of the Longmen Shan are somewhat mysterious, because the region shows relatively little sign of tectonic activity and has had very few historical earthquakes. Despite this quiescence, previous work by the PI and Co-I has shown that the faults in the Longmen Shan have been active in the geologically-recent past, with earthquakes in the last 10000 years. Two long faults in particular, the Beichuan and Pengguan faults, run almost the entire length of the Longmen Shan and show clear evidence of earthquakes during the last few thousands, and in some cases hundreds, of years. The rates of slip vary between fractions of mm per year to possibly many mm per year. The steep topography and high rainfall in the region, however, mean that the evidence of these past earthquakes is quickly lost through erosion, and so these estimates of slip rates and even the exact locations of the faults are very uncertain. The 12 May earthquake provides an unprecedented opportunity to view the geometry and sense of slip on the underlying faults, and to see the relationships between the short-term and long-term patterns of deformation that have created the Longmen Shan. In the proposed research, we will map the pattern of surface slip that occurred in the earthquake and measure the orientation and amount of slip at different points along the rupture zone. The earthquake appears to have occurred on the Beichuan fault, but the pattern of slip at the surface is complicated and it may be that more than one fault was involved in the earthquake. Untangling the details of such complexity is a good way of understanding the geometrical relationships between faults below the surface, and the way in which the faults have interacted and evolved over time. The distribution of slip in the earthquake can be directly compared to the pattern of damage to infrastructure and the occurrence of earthquake-triggered landslides. It can also be used to check and calibrate rapid, remote methods of estimating earthquake size, such as seismological or satellite-based remote sensing techniques.

2008年5月12日发生在中国四川省的7.9级地震摧毁了中国西部的大片地区。地震发生在世界上最陡峭、最崎岖的山脉——龙门山或龙门山的下面。龙门山的起源有些神秘，因为该地区显示出相对较少的构造活动迹象，历史上很少发生地震。尽管如此，PI和Co-I先前的工作表明，龙门山的断层在地质上最近的过去是活跃的，在过去的10000年里发生了地震。特别是两条长断层，北川断层和彭关断层，几乎延伸了龙门山的整个长度，在过去的几千年里，在某些情况下，几百年里，有地震的明显证据。滑移率从每年几毫米到每年可能多毫米不等。然而，该地区陡峭的地形和大量的降雨意味着过去这些地震的证据很快就会因侵蚀而消失，因此对滑动率甚至断层的确切位置的估计都是非常不确定的。5月12日的地震提供了一个前所未有的机会，可以观察潜在断层的几何形状和滑动感，并观察形成龙门山的短期和长期变形模式之间的关系。在拟议的研究中，我们将绘制地震中发生的地表滑动模式，并测量沿断裂带不同点的滑动方向和数量。这次地震似乎发生在北川断层上，但地表的滑动模式很复杂，可能有多个断层参与了这次地震。解开如此复杂的细节是理解地表以下断层之间几何关系的好方法，以及断层随时间相互作用和演变的方式。地震中滑动的分布可以直接与基础设施的破坏模式和地震引发的滑坡的发生进行比较。它还可以用于检查和校准快速、远程估计地震大小的方法，例如地震学或基于卫星的遥感技术。

项目成果

Dilution of 10Be in detrital quartz by earthquake-induced landslides: Implications for determining denudation rates and potential to provide insights into landslide sediment dynamics

• DOI: 10.1016/j.epsl.2014.03.058
• 发表时间: 2014-06
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: A. West;R. Hetzel;Gen K. Li;Zhangdong Jin;Fei Zhang;Robert G. Hilton;A. Densmore