Dr. Matt Purvance, Nevada Seismological Laboratory

Paper Version (PDF) (14 MB file size)

Power Point Presentation (29 MB file size)

"Overturning of Slender Blocks: Numerical Investigation and Application to Precariously Balanced Rocks in Southern California"

Abstract: The existences of precariously balanced rocks near to active faults in southern California represent a new source of data constraining ground motions over long time periods. In order to quantify these constraints, a large numerical experiment has been undertaken. In essence, a set of synthetic blocks have been exposed to many different ground motions. The overturning responses of these blocks have been parameterized via a regression analysis. In order to validate the formulation, comparisons between the numerical predictions and shake table experiments are presented. These results are subsequently applied to three sets of precariously balanced rocks in southern California. It will be shown that commonly utilized hazard estimates at these sites are inconsistent with the precariously balanced rocks. This new source of data may contribute fundamentally to our understanding to long term seismic hazard in southern California.