Estimates of Fault Strength, Frictional Heat, and Energy for the Chi-Chi, Taiwan Earthquake

台湾集集地震的断层强度、摩擦热和能量估计

基本信息

批准号：
16253003
负责人：
MORI James Jiro
金额：
$ 25.54万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

The main purpose of this project was to look for a temperature anomaly associated with faulting from the 1999 Chi-Chi, Taiwan earthquake (Mw7.6) on the Chelungpu fault. Any temperature change across the fault would give an estimate of the frictional heat produced at the time of the earthquake. Determining the level of frictional heat adds valuable information to a long-standing problem in seismology about the absolute stress levels and strengths of faults during large earthquakes. For the temperature measurements we able to use the Taiwan Chelungpu fault Drilling Project (TCDP) borehole which penetrated the fault at a depth of about 1100 meters in a region of large slip.Using a high-resolution borehole instrument developed in this project, we measured continuous temperature profiles in the borehole in September 2005. The results, which were obtained 6 years after the earthquake, showed a small increase of temperature across the fault. This small temperature signal is interpreted as the residual frictional heat from the time of the earthquake. The modeled temperature data showed that a shear stress level of 0.8 to 1.7 MPa on the fault during the rupture. This value corresponds to an apparent coefficient of friction of 0.08 to 0.1, which is a very low value. If this is a representative value for the area of large faulting, significant low friction mechanisms are needed to explain the faulting.Material properties, such as variations in heat conductivity, may affect the interpretation of the temperature signal. Investigating these effects is the purpose of a follow-up project. Other studies in the project investigated physical properties of the fault zone from the borehole cores and a water pumping test was done to determine the fluid flow properties.

该项目的主要目的是寻找与Chelungpu断层上1999年Chi-Chi（MW7.6）断层相关的温度异常。整个断层之间的任何温度变化都将估算地震时产生的摩擦热。确定摩擦热的水平为关于地震期间绝对应力水平和断层强度的地震学水平的长期问题增加了宝贵的信息。对于温度测量，我们能够使用台湾切伦普断层钻孔项目（TCDP）钻孔，该钻孔在该项目中开发的高分辨率钻孔仪器中渗透到大约1100米的故障的深度，我们在2005年9月的井眼中进行了较小的孔径，在该项目中，我们测量了连续的温度。从地震时期起，这种小温度信号被解释为残留的摩擦热。模型的温度数据表明，破裂期间断层的剪切应力水平为0.8至1.7 MPa。该值对应于0.08至0.1的明显摩擦系数，这是非常低的值。如果这是大断层区域的代表性值，则需要明显的低摩擦机制来解释断层。材料特性（例如热电导率的变化）可能会影响温度信号的解释。调查这些效果是后续项目的目的。该项目中的其他研究研究了钻孔核心的断层区的物理特性，并进行了抽水测试，以确定流体流量。

项目成果

期刊论文数量（13）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Slip zone and energetics of a large earthquake from the Taiwan Chelungpu-fault Drilling Project

DOI：
10.1038/nature05253
发表时间：
2006-11
期刊：
Nature
影响因子：
64.8
作者：
K. Ma;Hidemi Tanaka;Sheng-rong Song;C. Wang;J. Hung;Y. Tsai;J. Mori;Yen-Fang Song;Eh-Chao Yeh;W. Soh;H. Sone;L. Kuo;Hung-Yu Wu
通讯作者：
K. Ma;Hidemi Tanaka;Sheng-rong Song;C. Wang;J. Hung;Y. Tsai;J. Mori;Yen-Fang Song;Eh-Chao Yeh;W. Soh;H. Sone;L. Kuo;Hung-Yu Wu

Precise temperature measurement at TCDP Hole-A

TCDP A 孔的精确温度测量