Rupture History of the San Andrea Fault in the Carrizo Plan prior to 1200 AD

Project: Research project

Description

Earthquake ages and slip along the San Andreas Fault (SAF) over the last two millennia are required to achieve SCEC goals of physics-based seismic hazard analyses. Our ongoing work at the Bidart site along the south-central SAF in the Carrizo Plain indicates that the recurrence of large earthquakes is more rapid than expected (~140 versus ~235 years) and that the slip per event may be lower as well (~5 m not ~7-8 m). SCEC support will enhance our summer 2009 research at the Bidart site, allowing us to expand our excavation program, improve our geochronologic control, and mentor a SCEC intern.

Description

SCEC scientific objective A1 aims to constrain the earthquake history (including recurrence times and slip distribution) of the San Andreas fault system for the last 2000 years. An obvious first step towards achieving this goal is to study the slip distribution of the last great earthquake in Southern California (the 1857 Fort Tejon event). Support of this proposal will permit us to complete our investigation of the 1857 and earlier earthquake slip distributions as measured by careful study of the B4 LiDAR topography dataset. It will make a direct contribution towards scientific objective A1 and the goals of the Southern San Andreas Fault Evaluation (SoSAFE) project. We will make the tools used in our investigation (ProfilerGUI along with clear documentation and training) available to the SCEC community. The work will comprise an important portion of the dissertation of ASU student Olaf Zielke. We will prepare a manuscript for publication with supporting documentation for the Journal of Geophysical Research.

Description

We seek to investigate the effect of fault geometric roughness and structural complexity (e.g., segment separation, difference in strike) on earthquake rupture size and multi-segment rupture probability using a numerical earthquake simulator. We are participating with our simulator FIMozFric in the SCEC Numerical Earthquake Simulator workshops for simulator code validation and testing. Here, we propose to explore the spatial and temporal stability of fault segmentation and determine the probability of fault-to-fault rupture as a function of geometric fault roughness, fault separation, and difference in strike (science objective A9). Our study will constrain the characteristic earthquake magnitude and assess the predictability of rupture extent not only as a function of a fault segments length, but also its geometric and structural complexity (A9, A10), leading to a better understanding of the physical basis for earthquake predictability (A6). The results of the proposed study, together with the SCEC Community Fault Model (CFM), constrain magnitude and probability of large, single as well as multi-segment rupture events in southern California. It will thus make a direct contribution to the goals of the Working Group on California Earthquake Probabilities (WGCEP).
StatusFinished
Effective start/end date2/1/071/31/12

Funding

  • DOI-USGS: Earth Resources Observation and Science Center (EROS): $105,835.00

Fingerprint

rupture
earthquake
history
San Andreas Fault
simulator
roughness
plan
earthquake rupture
earthquake magnitude
seismic hazard
segmentation
excavation
physics
student
topography
summer
distribution