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by R.D. McJunkin
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Introduction
A moderate magnitude earthquake (ML = 5.7; Berkeley Seismographic Station) occurred
approximately 30 km northwest of Bishop, California at 16:42:47.3 (GMT)
on 4 October 1978. The earthquake had a focal depth of 4.8 km and was located
at latitude 37.518°N and longitude 118.705°W.
The Bishop area is moderately instrumented by 11 accelerograph sites within
100 km of the epicenter (Figure 1; Table 1). All instruments within the
100 km epicentral radius are owned and operated by the Office of Strong
Motion Studies (OSMS), California Division of Mines and Geology (CDMG). Five
of the eleven OSMS accelerograph stations were triggered (Figure 2) and
produced records of the Bishop earthquake.
Three accelerograph sites beyond the 100 km epicentral radius were triggered
by the 4 October 1978 earthquake. Two sites at the Pine Flat and Buchanan
Dams (Ed Etheredge, 1978, person. commun.) are instrumented by the USGS; the
third site, on the Fresno State University campus, is instrumented by OSMS.
Records from these three distant stations are very weak and were determined
to not be significant in comparison with data obtained from sites closer
to the epicenter. For this reason, data from the three distant sites are
excluded from this report.
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