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The north-northwest aftershock pattern of the June 28, 1992 Landers earthquake and the probability of large earthquakes in Indian Wells Valley

Conference · · Geological Society of America, Abstracts with Programs; (United States)
OSTI ID:5023084
 [1];  [2]
  1. Irvine Valley College, Irvine, CA (United States). Dept. of Geosciences
  2. California State Univ., Northridge, CA (United States). Dept. of Geological Sciences
Immediately following the June 28, 1992 Landers earthquake, a strong north-northwest pattern of aftershocks and triggered earthquakes developed. The most intense pattern developed between the north end of primary rupture on the Emerson fault and southern Owens Valley. The trend of seismicity cuts through the east-west trending Garlock fault at a high angle. The Garlock fault has no apparent affect on the trend or pattern. Within the aftershock zone, south of the Garlock fault, the Calico and Blackwater faults provide the most likely pathway for the Mojave shear zone into Indian Wells and Owens Valleys. In Indian Wells Valley the seismically active Little Lake fault aligns well with the Blackwater fault to the south and the southern Owens Valley fault zone to the north. Several recent research papers suggest that Optimum Coulomb failure stress changes caused by the Landers earthquake have enhanced the probability of earthquakes within the north-northwest trending aftershock zone. This increase has greater significance when the presumed Optimum Coulomb failure stress changes caused by the 1872 Owens Valley earthquake and its affects on Indian Wells Valley are considered. Indian Wells Valley and the Coso Volcanic field may have received two significant stress increases from earthquakes of magnitude 7.5 or greater in the last 120 years. If these two earthquakes increased the shear stress of aults in the Indian Wells/Coso areas, the most likely site for the next large earthquake within the Mojave shear zone may be there. The rate of seismicity within Indian Wells Valley had increased since 1980 including a magnitude 5.0 earthquake in 1982.
OSTI ID:
5023084
Report Number(s):
CONF-9305259--
Conference Information:
Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:5
Country of Publication:
United States
Language:
English