Letter abstract

Nature Geoscience 2, 581 - 584 (2009)
Published online: 26 July 2009 | doi:10.1038/ngeo590

Tectonic evolution of the Salton Sea inferred from seismic reflection data

D. S. Brothers1, N. W. Driscoll1, G. M. Kent1, A. J. Harding1, J. M. Babcock1 & R. L. Baskin2


Oblique extension across strike-slip faults causes subsidence and leads to the formation of pull-apart basins such as the Salton Sea in southern California. The formation of these basins has generally been studied using laboratory experiments or numerical models1, 2, 3, 4. Here we combine seismic reflection data and geological observations from the Salton Sea to understand the evolution of this nascent pull-apart basin. Our data reveal the presence of a northeast-trending hinge zone that separates the sea into northern and southern sub-basins. Differential subsidence (>10 mm yr-1) in the southern sub-basin suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline, which may control the spatial distribution of young volcanism. Rotated and truncated strata north of the hinge zone suggest that the onset of extension associated with this pull-apart basin began after approx0.5 million years ago. We suggest that slip is partitioned spatially and temporally into vertical and horizontal domains in the Salton Sea. In contrast to previous models based on historical seismicity patterns5, the rapid subsidence and fault architecture that we document in the southern part of the sea are consistent with experimental models for pull-apart basins1.

  1. Scripps Institution of Oceanography, University of California, San Diego, 9500, Gilman Drive, La Jolla, California 92093, USA
  2. United States Geological Survey, 2329 West Orton Circle, West Valley City, Utah 84119, USA

Correspondence to: D. S. Brothers1 e-mail: dbrother@ucsd.edu


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