U.S. Geological Survey Crustal Studies Technical Letter Number 1
U.S. Geological Survey instrumental seismic studies in the Parkfield-Cholame area consist of three related parts that were undertaken as pilot studies in a program designed to develop improved tools and concepts for investigating the properties and behavior of the San Andreas fault. These studies include:
1. The long=term monitoring of the seismic background on the San Andreas fault in Cholame Valley by means of a short-period Benioff seismograph station at Gold Hill.
2. The investigation of the geometry of the zone of aftershocks of the June 27 earthquakes by means of a small portable cluster of short-period, primarily vertical-component seismographs.
3. The seismic-refraction calibration of the region enclosing the aftershock source by means of three short reversed refraction profiles and a “calibration shot” near the epicenter of the main June 27 earthquake. This brief report outlines the work that has been completed and presents some preliminary results obtained from analysis of records from Gold Hill and the portable cluster.
For additional information:
This report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.
Eaton, J.P., 1967, The Parkfield-Cholame, California, earthquakes of June–August, 1966; instrumental seismic studies: U.S. Geological Survey Crustal Studies Technical Letter Number 1, 26 p. (Available at https://pubs.usgs.gov/misc/tl/0001/.)
Results from the Gold Hill Seismograph
Pre-Earthquake Seismic Activity
Relationships among Foreshocks, Main Shock, and Aftershocks
Frequency of Aftershocks
Record of Intense Ground Motion
Geometry of the Aftershock Source Region Southeast of Gold Hill
Seismic-Refraction Calibration of the Crust in the Aftershock Region