Investigation of Earthquake Sources and Fracture Origin of Crustal Seismic Coda Using Seismograms Recorded at Depth in the Cajon Pass Drillhole

利用Cajon Pass钻孔深处记录的地震图研究震源和地壳地震尾部断裂成因

• 批准号: 9219856
• 负责人: Peter Leary
• 金额: $ 12.17万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-05-01 至 1995-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9219856&HistoricalAwards=false
• 关键词: Investigation; Earthquake; Sources; Fracture; Origin

This research is to continue the recording and analysis of a triaxial set of 10 Hz geophones placed at a depth of 2.5 km in the Cajon Pass deep drill hole near the San Andreas fault in southern California. To date, the instrumentation has recorded several hundred earthquakes at frequencies up to 400 Hz. Most larger events were recorded simultaneously by a 2 Hz triaxial surface seismometer. Results suggest that surface seismograms are severely depleted in high frequency wave amplitudes and downhole seismograms have high corner frequencies and high frequency power law amplitude decays. Additional wide-band seismic sensors will be installed at 2.0 and 3.5 km depths in order to give an improved measure of natural seismicity and record microearthquake scaling in a volume of seismically active crust. This research is a component of the National Earthquake Hazard Reduction Program.

这项研究将继续对10 Hz地球座的三轴录制和分析，该集的深度为2.5 km，在南加州圣安德烈亚斯断层附近的Cajon Pass深钻孔中。 迄今为止，该仪器以高达400 Hz的频率记录了数百次地震。 大多数较大的事件是通过2 Hz三轴表面地震计同时记录的。 结果表明，表面地震图在高频波幅度中严重耗尽，井下地震图具有高角度频率和高频功率定律幅度衰减。 为了改善自然地震性的量度，将安装在2.0和3.5 km的深度下，将安装其他宽频段地震传感器，并记录微夸张的缩放。 这项研究是国家地震危害计划的组成部分。