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Holocene subaqueous paleoseismology of Lake Tahoe
Shane B. Smith et al., Dept. of Geological Sciences, University of Nevada, Reno, Nevada 89557-0172, USA. Posted online 11 Jan. 2013; http://dx.doi.org/10.1130/B30629.1.
Large subaqueous landslides and turbidites in Lake Tahoe suggest that strong shaking due to earthquakes (greater than magnitude 7) in or near the basin occurs every 800 years on average with the most recent event occurring about 500 years ago. This study by Shane Smith and colleagues provides the first continuous strong shaking record in the region spanning the Holocene and indicates that perhaps fourteen episodes have occurred during the past 12,000 years. Carbon-14 dating of the subaqueous deposits compares favorably to the record of known paleoseismic events on nearby faults. The size and location of the deposits also allows the researchers to determine when individual faults have ruptured. The West Tahoe fault, the largest fault in the basin, ruptured about 4,500, 5,600, and 7,800 years ago, giving a recurrence interval of about 2,600 years. The event about 4,500 years ago may not have ruptured the central and northern segments of the fault. More studies are needed to better define the seismic hazard in the Reno/Ta
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