Abstract
In 1872, a magnitude 7.5-7.7 earthquake vertically offset the Owens Valley fault by more than a meter. An eyewitness reported a large wave on the surface of Owens Lake, presumably initiated by the earthquake. Physical evidence of this event is found in cores and trenches from Owens Lake, including soft-sediment deformation and fault offsets. A graded pebbly sand truncates these features, possibly over most of the lake floor, reflecting the 'tsunami' wave. Confirmation of the timing of the event is provided by abnormally high lead concentrations in the sediment immediately above and below these proposed earthquake deposits derived from lead-smelting plants that operated near the eastern lake margin from 1869-1876. The bottom velocity in the deepest part of the lake needed to transport the coarsest grain sizes in the graded pebbly sand provides an estimate of the minimum initial 'tsunami' wave height at 37 cm. This is less than the wave height calculated from long-wave numerical models (about 55 cm) using average fault displacement during the earthquake. Two other graded sand deposits associated with soft-sediment deformation in the Owens Lake record are less than 3000 years old, and are interpreted as evidence of older earthquake and tsunami events. Offsets of the Owens Valley fault elsewhere in the valley indicate that at least two additional large earthquakes occurred during the Holocene, which is consistent with our observations in this lacustrine record. (C) 2000 Elsevier Science B.V. All rights reserved.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 241-254 |
| Number of pages | 14 |
| Journal | Sedimentary Geology |
| Volume | 135 |
| Issue number | 1-4 |
| DOIs | |
| State | Published - 2000 |
Bibliographical note
Funding Information:We are especially grateful to Eric Geist, USGS, who provided the numerical modeling of the tsunami waves, supplied a computer code for the Okada (1992) equations, and provided much advice on solving tsunami wave characteristics from fault data. We thank Paul Lamos of the Lake Minerals Corporation, Lone Pine, for access to trenches and roads on Owens Lake and for considerable logistical assistance in accomplishing this study. Previously unpublished radiocarbon samples were prepared by the lab of Jack McGeehin, USGS, and carbon dates were provided by the Center for Accelerator Mass Spectroscopy of the Lawrence Livermore Laboratory. Steve Obermeier and John Sims, USGS, reviewed an early version of this manuscript. Kevin Foley, USGS, ran the Okada (1992) computer code and provided output orthogonal to the fault for the two-dimensional wave model. Chiang Mei, MIT, offered a simple solution to the wave problem based on these data which we used in an earlier version of the paper. The USGS Climate History Program, Warm Intervals Project, funded this work. We thank Kathy Cummins and John Fitzpatrick for doing Pb analyses.
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
Keywords
- California
- Earthquake record
- Lacustrine sediments
- Tsunamis
