Recurrent Holocene faulting along the Johnson Valley portion of the 1992 Landers earthquake surface rupture

Conference · Thu Apr 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5126186

Lindvall, S C ^[1]; Rockwell, T K ^[2]

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1. Lindvall-Richter-Benuska, Los Angeles, CA (United States)
2. San Diego State Univ., CA (United States). Dept. of Geological Sciences

Five trenches excavated across the surface rupture associated with the 1992 Landers earthquake (M7.5) in Johnson and Homestead Valleys, Mojave Shear Zone, southern California, indicate that recurrent Holocene faulting has occurred on at least the southern Johnson Valley, Landers, and Homestead Valley faults. The stratigraphy in one trench across the southern Johnson Valley fault, which sustained 3 m of strike-slip in 1992, expresses evidence for at least three events during the Holocene, based on the presence of colluvial wedges, abrupt truncation of fault splays, stone lines and buried soils. The Landers fault, which accommodated about 2.5 m of slip in 1992, crosses Johnson Valley and allowed the rupture to continue to the north to connect with the Homestead Valley fault. Trenching across the Landers fault, south of Bodick Road, also demonstrates recurrent Holocene activity, with the penultimate event possibly being very recent. Two trenches across a secondary thrust fault along the Homestead Valley portion of the rupture records only one other possible Holocene event. Although the seismic record may not be complete along this secondary fault, the dissimilarity in rupture history with the other two faults suggested by these trenches may indicate that some of the Johnson Valley-Landers fault events may not have been broken with the Homestead Valley fault, as did the 1992 rupture.

• OSTI ID: 5126186
• 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

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CALIFORNIA
CENOZOIC ERA
DEVELOPED COUNTRIES
EARTHQUAKES
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
NORTH AMERICA
QUATERNARY PERIOD
SEISMIC EVENTS
SEISMICITY
STRATA MOVEMENT
STRATIGRAPHY
USA