HR: 0830h
AN: S21F-0389    [PDF]
TI: Modeling Of LARSE II Refraction Data In The Western Mojave Desert, California
AU: * Lim, K
EM: kolim@mtu.edu
AF: Michigan Technological University, Geological and Mining Engineering and Mining Sciences, 1400, Townsend Dr,, Houghton, MI 49931 United States
AU: * Lim, K
EM: kolim@mtu.edu
AF: USGS, 345, Middlefield Rd, Menlo Park, 94025 United States
AU: Baher, S
EM: sbaher@usgs.gov
AF: USGS, 345, Middlefield Rd, Menlo Park, 94025 United States
AU: Fuis, G
EM: fuis@usgs.gov
AF: USGS, 345, Middlefield Rd, Menlo Park, 94025 United States
AB: The major goals of the LARSE II (Los Angeles Region Seismic Experiment, Part II) are to image the subsurface in Los Angeles region utilizing reflection and refraction surveys, to understand the detailed structure of the subsurface in relation to earthquakes. LARSE II data acquisition was accomplished in October 1999 along the 150km long main line that extended from Santa Monica Bay to the western Mojave Desert. We modeled LARSE II refraction data in the western Mojave Desert using a forward modeling technique, fitting the first arrivals in most cases less than 0.05 second. In general, layers were modeled to match the breaks in slope of the first arrival branches. Three layers over basement were modeled. They have velocities or velocity ranges (in km/s) of 1.0 or less (Layer 1), 2.0-3.4 (Layer 2) and 3.3-3.9 (Layer 3). Preliminary interpretations are as follow: Layer 1, up to 0.2km thick, is unsaturated, unconsolidated Quaternary sediments. Layer 2 and 3, which thicken to a total of 1.5km in the central Mojave Desert, are Quaternary and Tertiary sedimentary rocks. An oil-test well in the southern Mojave Desert bottoms at the base of Layer 3 (1.04 km depth) in the Tertiary rocks. An oil-test well in the northern Mojave Desert bottoms in the basement (quartz diorite) at the depth of 1.01km. Upward steps in basements can be seen on the north and south sides of the western Mojave Desert, at or near mapped faults. In summary, maximum depth to basement is 1.7 km in the western Mojave Desert.
DE: 7200 SEISMOLOGY
SC: Seismology [S]
MN: 2003 Fall Meeting