Insights into Earthquake Propagation Processes from the Chelungpu Fault Drilling, Project, Taiwan

0098108 Evans 1999年9月，台湾车笼埔断层发生大地震。 断层形成了台湾中部高地和沿着台湾岛西侧的沿海平原之间的边界。 这次地震造成2400人死亡，约110亿美元的损失，沿着85公里长的地表破裂形成了壮观的断层陡坎。车楞堡破裂说明了地震破裂动力学和地震危险性分析的相关问题之一--地震能量如何辐射到地表，导致与大地震有关的滑动和地面运动分布的近地表条件是什么？ 日本地球物理界在日本科学技术省（JAMSTEC）的资助下，计划通过在两个地点的断层尖端钻两个300 m的孔来解决这个问题和相关问题。 这些取芯孔将检查断层带的特征，并试图解决有关近地表区域滑动传播性质的问题。 这些取芯孔提供了一个独特的机会，使我们能够将对断裂带结构的理解扩展到古地震学研究中通常检查的范围之外，进入一个对断裂带的结构和组成及其与地震能量辐射或分散的关系知之甚少的地区。该奖项将允许主要研究者利用这一难得的机会，最近破裂断层提供资金的全套钻孔地球物理测井，并提供两个-现场构造地质学家合作进行两个钻孔的初始岩心测井和钻孔地球物理测井。 他们将分析钻孔数据，并与日本和台湾地质学家合作，整合详细的地表破裂痕迹图，基岩暴露图和浅层地震反射数据，以提供断层带的详细描述，包括断层组成和结构，流体特征，高滑动带的位置和性质。 将采集样品进行进一步的测试和分析。钻探将于2000年11月开始，持续约两个月，因此本次SGER请求的时间紧迫。 通过国际合作和综合方法，这项工作将提供地球上千米主要发震断层的过程和结构的详细视图，并对大地震期间地震能量到达地球表面的过程产生重要的新见解。

0098108EvansIn September 1999 a large earthquake occurred on the Chelungpu fault in Taiwan. The fault forms the boundary between the highlands of central Taiwan and the coastal plain along the western side of the island. The earthquake resulted in 2400 fatalities, ~$11 billion in damage, and the development of spectacular fault scarps along an 85Km long surface rupture.The Chelengpu rupture illustrates one of the outstanding questions in earthquake rupture dynamics and the related issues of earthquake hazard analysis - how does seismic energy radiate to the ground surface, and what are the near surface conditions that lead to the distribution of slip and ground motion associated with large earthquakes? The Japanese geophysical community, with funding from the Japanese Ministry of Science and Technology (JAMSTEC), plans to address this and related questions by drilling two 300-m holes through the tip of the fault at two sites. These cored holes will examine the character of the fault zone and attempt to address questions regarding the nature of slip propagation in the near surface region. These cored holes provide a unique opportunity to extend our understanding of fault zone structure beyond that typically examined in paleoseismological investigations into a region where very little is known about the structure and composition of the fault zone and its relationship to the radiation or dispersal of seismic energy.This Small Grant for Exploratory Research (SGER) award will allow the Principal Investigator to take advantage of this rare opportunity to investigate the near surface tip zone of a large, recently rupture fault by providing funds for the full suite of borehole geophysical logs and to provide two on-site structural geologists to collaborate on the initial core logging and borehole geophysical logging of the two holes. They will analyze the borehole data, and integrate detailed surface rupture trace maps, bedrock exposure mapping, and shallow seismic reflection data in collaboration with Japanese and Taiwanese geologists, to provide a detailed description of the fault zone, including fault composition and structure, fluid characteristics, location and nature of the high-slip zones. Samples will be collected for further testing and analysis.Drilling will begin in November 2000 and last for approximately two months, thus the time urgency of this SGER request. This work, through international collaboration and integrated methodologies, will provide a detailed view of the processes and structure of a major seismogenic fault in the upper km of the earth, and yield significant new insights into the processes by which seismic energy reaches the earth's surface during large earthquakes.***