Location of earthquake swarm events near Palmdale, California, using a linear gradient velocity model
- Creators
- Drowley, Dayna Salter
- McNally, Karen C.
Abstract
A series of small earthquakes (0.5 ≦ M_L ≦ 3.0) along a 60-km segment of the San Andreas Fault in the vicinity of Palmdale, California, has been recorded since 1976 by an array operated by the California Institute of Technology. The events were analyzed in two steps. First, travel-time data from four regionally well-recorded events (M_L = 2.2, 2.8, 3.0, 2.8) were inverted using a nonlinear least-squares algorithm to obtain a local velocity model consisting of an upper crustal layer with linearly increasing velocity in dipping contact with a constant velocity half-space. Hypocenters of over 150 events were relocated using this velocity model. Most of the events are clustered between the mapped traces of the San Andreas and Punchbowl faults; however, there has been a migration of activity along the San Andreas Fault. Activity which began in a 5-km cluster has expanded during a 2-yr period to fill a 60-km segment of the fault.
Additional Information
© 1980, by the Seismological Society of America. Manuscript received January 6, 1980. We would like to thank Dr. L. R. Johnson for his advice and help in the development of the computer program used in this study, and the many useful suggestions he provided throughout the course of the study. We would also like to thank Drs. Hiroo Kanamori and T. V. McEvilly for helpful suggestions, and Mary French for reading the arrival times for all the events used in this study. This research was partially supported by the Advanced Research Projects Agency of the Department of Defense and was monitored by the Air Force Office of Scientific Research under Contract F49620-79-C-0028 (DSD} and by the U.S. Geological Survey Contracts 14-08-0001-16711 and 14-08-001-17631 (KCM).Attached Files
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Additional details
- Eprint ID
- 49289
- Resolver ID
- CaltechAUTHORS:20140905-112552747
- Advanced Research Projects Agency (ARPA)
- F49620-79-C-0028
- Air Force Office of Scientific Research (AFOSR)
- 14-08-0001-16711
- USGS
- 14-08-001-17631
- USGS
- Created
-
2014-09-05Created from EPrint's datestamp field
- Updated
-
2019-10-03Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological and Planetary Sciences
- Other Numbering System Identifier
- 3348