COLLABORATIVE RESEARCH: In Situ and Laboratory Measurement of Seismic Velocity Across an Exposed Brittle Fault Gouge Zone

合作研究：现场和实验室测量暴露的脆性断层泥带的地震速度

基本信息

批准号：
9909376
负责人：
John Hole
金额：
$ 8.61万
依托单位：
Virginia Polytechnic Institute and State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
1999
资助国家：
美国
起止时间：
1999-12-15 至 2001-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9909376&HistoricalAwards=false
关键词：
COLLABORATIVE RESEARCH Situ Laboratory Measurement

项目摘要

Hole 9909376 In crustal faults such as the San Andreas and subduction zone megathrusts, anomalous seismic velocity, seismic reflectivity, and electrical conductivity have been interpreted as signatures of fluid content, pore pressure, fault gouge presence or composition, and damage zone effects. However, the relative contribution of these factors to detectable fault zone properties is poorly known. The PIs will conduct a combined field and laboratory study of seismic velocity and electrical conductivity across an unweathered exposure of the active Seal Cove strand of the San Gregorio Fault in Moss Beach, California. Compressional and shear wave velocity and anisotropy and electrical conductivity will be measured in the field through very high-resolution seismic and resistivity surveys, and in the laboratory on representative samples at elevated pressure. Field measurements will document long length-scale effects that cannot be sampled in the laboratory, bridging the gap between laboratory and geophysical field data, while the experimental data will document pore pressure and stress effects at depth and the relationship of physical properties to lithology and structural geology. The results will be used along with existing lithologic and structural data to create an integrated model of fault zone physical properties.

孔 9909376 在圣安地列斯和俯冲带巨型逆冲断层等地壳断层中，异常地震速度、地震反射率和电导率已被解释为流体含量、孔隙压力、断层泥存在或成分以及损伤带效应的特征。然而，这些因素对可检测断层带特性的相对贡献却鲜为人知。 PI 将对加利福尼亚州莫斯海滩圣格雷戈里奥断层未风化暴露的活动海豹湾线的地震速度和电导率进行现场和实验室联合研究。压缩波和剪切波速度以及各向异性和电导率将通过极高分辨率地震和电阻率勘测在现场测量，并在实验室中在高压下对代表性样品进行测量。现场测量将记录实验室无法采样的长尺度效应，弥合实验室和地球物理现场数据之间的差距，而实验数据将记录深度的孔隙压力和应力效应以及物理性质与岩性和结构的关系地质学。结果将与现有的岩性和结构数据一起用于创建断层带物理性质的综合模型。