HR: 1340h
AN: S43C-1029    [Abstracts]
TI: The Shallow Fault structure of the Incline Village Fault, Lake Tahoe NV, From Offshore Ultra High Resolution CHIRP Profiling and Onshore Paleo-Seismic Trenching.
AU: * Dingler, J A
EM: jdingler@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr 0225, La Jolla, CA 92093-0225 United States
AU: Seitz, G
EM: seitz3@earthlink.net
AF: San Diego State University, Dept of Geological Sciences San Diego State University, San Diego, CA 92182 United States
AU: Kent, G
EM: gkent@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr 0225, La Jolla, CA 92093-0225 United States
AU: Babcock, J
EM: jbabcock@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr 0225, La Jolla, CA 92093-0225 United States
AU: Brothers, D
EM: dbrother@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr 0225, La Jolla, CA 92093-0225 United States
AU: Karlin, B
EM: Karlin@mines.unr.edu
AF: University of Nevada, Reno, Department of Geological Sciences University of Nevada Reno, Reno, NV 89557 United States
AU: Driscoll, N
EM: ndriscoll@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr 0225, La Jolla, CA 92093-0225 United States
AU: Harding, A
EM: aharding@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr 0225, La Jolla, CA 92093-0225 United States
AB: The shallow fault structure of the Incline Village fault, Lake Tahoe NV, has been mapped using a combination of sub-meter resolution seismic CHIRP profiling, conventional paleo-seismic trenching on-shore, and shallow remotely operated vehicle (ROV) imagery. The pairing of these geophysical and geologic techniques has provided new insights into the fault history of the active Incline Village fault. These data, combined with previous off-shore surveys of the Stateline and West Tahoe faults, will help constrain the extensional history of the Tahoe Basin. Six new CHIRP dip profiles and three strike profiles were collected this past summer along a submerged, late Pleistocene (19.2 +/- 1.8ka) paleo-terrace just offshore of Incline Village, NV, and show a well-defined normal fault zone with >2m of vertical offset across the paleo-terrace. The sediment draped hanging wall shows evidence of at least one prominent colluvial wedge. A 6+ m paleo-seismic trench was also excavated at the Incline Village Elementary School, some 1000 m from the shoreline, which was sited based on a reconnaissance CHIRP profile collected in 2000. Trenching results are complementary with the chirp profiles and show three colluvial wedges with more than 2 meters of vertical offset for each of the events. These preliminary results have strong implications for understanding the evolution of the Walker Lane dextral shear-zone, which defines the western boundary of the Basin and Range.
DE: 7221 Paleoseismology
DE: 7223 Seismic hazard assessment and prediction
DE: 8010 Fractures and faults
DE: 8015 Local crustal structure
DE: 3025 Marine seismics (0935)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting