AGU session S18: Topography Effects in Ground Motion Predictions: From Numerical Modeling to Engineering Design

S18: Topography Effects in Ground Motion Predictions: From Numerical Modeling to Engineering Design
(http://www.agu.org/meetings/fm09/program/scientific_session_search.php?s...)

Seismic hazard assessment and microzonation studies rely increasingly on wave motion simulations, which provide surface motion accelerations for given seismic input scenarios. By and large, most developments to date do not account for topographical features, making the sweeping assumption of a flat earth surface model. Observations from large earthquakes, however, have shown that the presence of a strong topographic relief can significantly aggravate the catastrophic consequences of strong seismic motion. These effects of topography on site response may not be predicted by the widely employed flat surface models, leading to recently developed wave motion simulation tools that take into account local topography. While there is qualitative agreement between predictions and observations on topography effects, however, there is clear quantitative discrepancy: numerical predictions of crest-to-base amplification factors for the most part underestimate amplification values observed in the field. Furthermore, despite the documented evidence of their role in elevating seismic risk, topography effects are not accounted for in the majority of seismic code provisions and microzonation studies. The purpose of this session is to facilitate the dissemination of recent advances in the understanding, monitoring, modeling and simulation of topographic amplification of seismic ground motion, and to focus attention on the implications of topographic effects in seismological research and engineering design. Specific topics should include, but not be limited to, efficient methods for forward wave propagation modeling, observations of topographic amplification, and simplified procedures to account for topographic amplification phenomena in currently employed seismic hazard assessment and mitigation procedures.

See everyone in San Francisco! -- Dominic Assimaki (dominic@gatech.edu) and Alan Yong (yong@usgs.gov)

Thank you very much!

Cheers,
Alan
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Alan Yong
Research Geophysicist
DEPARTMENT OF THE INTERIOR
UNITED STATES GEOLOGICAL SURVEY
Earthquake Hazards Team
525 S. Wilson Ave.
Pasadena, CA 91106
(626)583-7816
yong@usgs.gov
yong@gps.caltech.edu
http://pasadena.wr.usgs.gov/office/yong