SCEC Award Number 14008 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title Collaborative Research: Documentation of Tsunami Deposits in the Carpinteria and Goleta Slough Estuaries: A signal of Great Earthquakes on the Pitas Point Thrust
Name Organization
Alexander Simms University of California, Santa Barbara Thomas Rockwell San Diego State University Robert Peters Robert Peters Geologic Bruce Jaffe United States Geological Survey Bruce Richmond United States Geological Survey
Other Participants Laura Reynolds (UCSB PhD Student), Another UCSB graduate student TBD
SCEC Priorities 1a, 2a, 4a SCEC Groups Geology, SoSAFE, USR
Report Due Date 03/15/2015 Date Report Submitted N/A
Project Abstract
The purpose of this project was to determine whether proposed large earthquake events along the Ventura Avenue Anticline-Pitas Point Thrust system (VAA-PPT) are recorded in the stratigraphy of Carpinteria and Goleta Sloughs. This year we specifically set out to 1.) better constrain the age of submergence events in Carpinteria Slough, 2.) determine whether the same events are recorded in Goleta Slough, and 3.) build a micro-fossil transfer function to quantify relative sea-level changes across these events. This year we obtained 59 new radiocarbon dates, 11 new cores up to 21 m in length, and surveyed the elevations of foraminifera in 3 estuaries in southern California. We have found evidence for 3 submergence events in Carpinteria Slough at 1.9-2.0, 3.4-3.6, and 4.0-4.2 ka. Another emergence event was found at 6.0 ka. The youngest of these events has also been identified in Goleta Slough. Preliminary findings also suggest that foraminifera are zoned by elevation within Carpinteria Slough and provide a means of quantifying subsidence in southern California. Our data suggests that at least 2 of the large earthquake events proposed to have occurred on the VAA-PPT are coeval with the timing of major events within Carpinteria Slough and the youngest may also have a stratigraphic signature recorded in Goleta Slough.
Intellectual Merit This project has led to an awareness of the potential of coseismic-subsidence in the coastal regions of southern California. The project is also providing data needed to evaluate the fault-geometry models within one of SCEC’s defined Special Fault Study Areas - the Ventura Avenue Anticline – Pitas Point Thrust (VAA-PPT) system. We are also establishing some of the first estimates of subsidence along subsiding portions of the southern California Coast.
Broader Impacts The broader impacts of this project include better defining the potential earthquake hazards along a populated coast, training future STEM researchers, and building research collaboration. This proposal has supported the research of two graduate students and two undergraduate students. Three of these students are female. This project has also helped to build active research collaboration among the USGS, UCSB and San Diego State University.
Exemplary Figure Figure 3