Characterization of recent Lake Tahoe fault activity: Combining Sub-Meter Resolution Seismic Imagery with AMS C-14 Dated Submerged Paleo-Surfaces.
Abstract
Deformational strain within the Lake Tahoe Basin was mapped during previous campaigns using a combination of high resolution seismic CHIRP, multi-beam swath bathymetry, and airborne laser altimetry. These previous campaigns identified submerged paleo-shorelines of Pleistocene to early Holocene age, which act as a tectonic strain marker due to fault related disruptions of this once flat surface, as well as significantly offset fault scarps. Building upon this previous work, specific sites were selected for additional investigation with seismic CHIRP and AMS C-14 dated vibra and piston cores. The combination of these three techniques is ideally suited for quantifying recent fault activity through the correlation of paleo-surfaces and accurate age determinations. Initial analysis of seismic CHIRP and piston coring conducted in Emerald Bay shows a complex normal fault system with a sedimentation rate much higher than other parts of the lake. Seismic CHIRP conducted near Zephyr Cove was able to image multiple paleo-shorelines. Vibra coring of these same surfaces recovered sands of the same consistency as beach sand. Additional piston cores were collected at various lake locations below 400 m depth, including two cores taken across the Stateline Fault. Core analysis and AMS C-14 dating combined with site-specific seismic CHIRP, and previous mapping, will improve chronological control on the fault activity within the Lake Tahoe Basin.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.S71B1095D
- Keywords:
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- 7221 Paleoseismology