Reconnaissance field investigation of the Landers earthquake (Ms 7.5) of June 28, 1992, San Bernadino County, California, USA
The Landers earthquake (Ms 7.5) occurred at 4.58 am local time, and was located about 10 km north of the town of Yucca Valley, close to the small town of Landers, and about 170 km ENE of Los Angeles (Fig. 1). At the time the author was in Reno, Nevada, involved in a field study of the 1915 rupture of the Pleasant Valley fault. Fieldwork was completed on July 8, and on July 9 the author drove with a Reno-based colleague, Dr. Steven Wesnousky, firstly to Los Angeles to consult with seismologists and geologists at U. S. Geological Survey (Pasadena) and California Institute of Technology (Caltech), and then to Yucca Valley to inspect surface faulting and damage in the epicentral area. We reached Yucca Valley at about 6 pm on July 10, and remained in the area until the evening of July 14.
Some objectives in inspecting the fault rupture were to look at the distribution of slip along the length of the fault break; the relationship of faulting to pre-existing traces; and the relationship of the fault rupture to the total length of each of the faults that ruptured. The earthquake magnitude and total rupture length are similar to what has been proposed for the segment of the Wellington fault that runs through the Wellington metropolitan area.
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Copyright (c) 1992 Kelvin Berryman
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