Area highlighted is the Cascadia Subduction Zone. Credit: USGSA comprehensive study of the potential for tsunamis in northwestern California, co-written by UCSB Earth Science professors Edward Keller and Alexander Simms and published in the June issue of the Bulletin of the Seismological Society of America, was based on the Ph.D. dissertation of UCSB alum Dr. David Valentine.
David earned his Ph.D. in Geologic Sciences at UCSB in 2000. Now a research programmer at the Spatial Information Systems Laboratory at UC San Diego, David was a student of Professor Keller’s and is first author of the paper.
The comprehensive, evidence-based work centered on the southern end of the Cascadia Subduction Zone (CSZ), which runs north from Mendocino, Calif. The authors studied sedimentation patterns in floodplains, estuaries, and salt marshes in the northwest corner of California for signs of seismic activity that could lead to tsunamis. An earthquake can cause coastal wetlands to become submerged, the researchers said, with sediment covering plants and animals inhabiting the area. This fossilized evidence points to a sea-level change in the region.
The research showed that the area had experienced three major quakes over the last 2,000 years, with sea-level changes at intervals of 300 to 400 years.
David told OurAmazingPlanet that in a subduction earthquake, the land “drops back down because the stress is released.” The size of the drop indicates the quake’s magnitude, he told the website.
For more information about the study, read the UCSB Office of Public Affairs press release, and OurAmazingPlanet’s interview with David.