Persistent Segmentation, Stress Triggering and Energy Management of the Sumatran Subduction Zone

Oregon State University, Corvallis OR

Investigators

Abstract

On a previously OCE funded study in 2007 the PI collected cores, bathymetric and CHIRP seismic data to develop a long-term spatial and temporal paleoseismicity record of the Sumatran-Andaman subduction zone. Current continuation request will allow the PI to obtain more radiometric dates, further analyses of the cores and correlation of the seismic, turbidite, and offshore and onshore data. The objectives are to test for the persistence of segment boundaries, the significance of clustering behavior, and the evidence for long-term energy patterns or "supercycles" suggested by current onshore-offshore paleoseismic data. This phase of the study will also address fundamental recurrence model, segmentation, inter-segment stress triggering and long-term energy management of the multi-segment Sumatran subduction zone. Time-series analysis will be extended and refined with additional 180 14-C dates, CT, ITRAX, X-ray and XRF and high-resolution seismic profile analyses. The time series for each segment will be modeled to assess the energy state of the fault, balancing strain accumulation vs. strain release over the last 7ky record. Broader impacts include a strong seismic hazard component to this work that could lead to a more refined and credible turbidite methodology for the study of paleoseismicity. International collaborations are also strong - involving a graduate student from Indonesia at OSU and collaboration with scientists from Indonesia, and with the National Oceanography Centre, Southampton, the Geological Survey of Japan and the Earth Observatory of Singapore. The project also includes the final 1.5 years of a PhD student at OSU.