NEHRP Clearinghouse
- Title
- Report for Borehole Explosion Data Acquired in the 1999 Los Angeles Region Seismic Experiment (LARSE II), Southern California: Part 1. Description of the Survey.
- File
- PB2006105467.pdf
- Author(s)
- Fuis, G. S.; Murphy, J. M.; Okaya, D. A.; Clayton, R. W.; Davis, P. M.
- Source
- January 2001, 82 p.
- Identifying Number(s)
- USGS/OFR-01-408
- Abstract
- The Los Angeles Region Seismic Experiment (LARSE) is a joint project of the U.S. Geological Survey (USGS) and the Southern California Earthquake Center (SCEC). The purpose of this project is to produce seismic images of the subsurface of the Los Angeles region down to the depths at which earthquakes occur, and deeper, in order to remedy a deficit in our knowledge of the deep structure of this region. This deficit in knowledge has persisted despite over a century of oil exploration and nearly 70 years of recording earthquakes in southern California. Understanding the deep crustal structure and tectonics of southern California is important to earthquake hazard assessment. Specific imaging targets of LARSE include (a) faults, especially blind thrust faults, which cannot be reliably detected any other way, and (b) the depths and configurations of sedimentary basins. Imaging of faults is important in both earthquake hazard assessment but also in modeling earthquake occurrence. Earthquake occurrence cannot be understood unless the earthquake-producing machinery (tectonics) is known. Imaging the depths and configurations of sedimentary basins is important because earthquake shaking at the surface is enhanced by basin depth and by the presence of sharp basin edges. Sedimentary basins in the Los Angeles region that have been investigated by LARSE include the Los Angeles, San Gabriel Valley, San Fernando Valley, and Santa Clarita Valley basins.
- Keywords
- Explosions; Shot points; California; Permitting; Seismic acquisition; Boreholes; Water levels; Sedimentary basins; Shot holes; Shot-size determination; Los Angeles Region Seismic Experiment (LARSE II); Surveys; Geologic setting; Seismic images; Earthquakes