SCEC Award Number 14198 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title Three Dimensional excavation of a 5m offset channel in the Carrizo Plain: Sieh31
Name Organization
Sinan Akciz University of California, Los Angeles Lisa Grant Ludwig University of California, Irvine J Ramon Arrowsmith Arizona State University
Other Participants Emily Kleber (ASU graduate student); 1-2 UCLA undergraduate volunteers
SCEC Priorities 2a, 1d, 4c SCEC Groups SoSAFE, WGCEP, USR
Report Due Date 03/15/2015 Date Report Submitted N/A
Project Abstract
We proposed to reevaluate the surface displacement of the great 1857 Fort Tejon earthquake along the central portion of the Carrizo section of the San Andreas Fault (SAF) with three dimensional excavation of channel Sieh31, a feature which has been interpreted to have been offset by ~9m or ~6m by different research groups. We suspended the excavation effort because of abrupt changes in responsibility levels, the tight budget, limited availability of the team, and because we were very concerned that our plan would not sufficiently document the subsurface offset features at all depth levels. The resources have gone to general support of related projects by our team focusing on paleoseismology, slip rates, and the development of a geomorphic-sedimentologic-tectonic model for the evolution of offset channel systems.
Intellectual Merit Cumulative slip and slip per event in paleoearthquakes are essential constraints on earthquake system behavior. Gathering this knowledge requires a well developed understanding of the behavior of the fault crossing markers (small channels).
Broader Impacts This project has rich broader impacts value as an illustration of the effect of fault slip on the landscape in dramatic high resolution topography with applications to formal and informal geoscience education. It has supported the research of 2 of graduate students at Arizona State University. The methodology developed is an essential element for data gathering for future activities such as updates to the Uniform California Earthquake Rupture Forecast.
Exemplary Figure Figure 5: Geomorphic-sedimentological model for offset channel development: fluvial and colluvial channel interactions in the offset channel system (Kleber, et al., 2014). This includes both the ~6kyr old channel at Phelan Creeks and the several hundred year old Sieh31 channel. Their association enables us to make a space for time substitution in our development and testing of the conceptual model.