(Santa Barbara, Calif.) Using studies that span the last three decades, scientists at UC Santa Barbara have compiled the first evidence-based comprehensive study of the potential for tsunamis in Northwestern California. The paper, "Paleoseismicity of the Southern End of the Cascadia Subduction Zone, Northwestern California," was co-written by professors Edward Keller and Alexander Simms from UCSB's Department of Earth Science, and published in a recent issue of the Bulletin of the Seismological Society of America.
The paper is based on the Ph.D. dissertation of David Valentine, a research programmer at the Spatial Information Systems Laboratory at UC San Diego. Valentine, Keller's former student, completed his doctorate at UCSB in 2002 and is first author of the paper.
The region has long been known to experience large earthquakes, and scientific studies of seismic activity in the southern end of the Cascadia Subduction Zone (CSZ) which stretches northward from the area of Mendocino, Calif. have previously appeared in grey literature and in guidebooks. However, comprehensive, reviewed evidence-based work has been lacking, according to Keller.
"Science goes on evidence," he said, adding that in light of the recent earthquakes in Japan and Chile, the study of the same potential closer to home is "timely." The authors studied sedimentation patterns in salt marshes, floodplains, and estuaries in the northwestern corner of California for signs of seismic events that could lead to tsunami activity. They combined this with information gathered from numerous studies conducted over nearly 30 years by researchers at Humboldt State University
During an earthquake, the researchers say, there is a tendency for the coastal wetlands to become submerged, with coastal sediments depositing over plants and animals that live there. These become a fossilized record of sea-level change in the area.
The process has preserved a se
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University of California - Santa Barbara