A lecture on "Development of Current Practice in Site Characterization for Acquiring Vs and Vs30" by Alan Yong who is a Research Geophysicist at the US Geological Survey Earthquake Science Center will be held at DPRI, Main Building Room E-417D, Uji Campus, Kyoto University, Kyoto, Japan on 24 January 2018 from 15:00-17:00 hours.



Alan Yong is a Research Geophysicist at the US Geological Survey Earthquake Science Center since 2009; from 1998-2009, Yong served as Operational Geophysicist. Yong received his MSc in Geophysics and Geology at the California State University Northridge in 2009. His research interests are mainly focused on engineering seismology and in particular, about near-surface geophysics. Yong co-leads the USGS US-wide Site Characterization Task and serves as Chair of the Steering Committee for the development of the Consortium of Organization for Strong Motion Observations Systems (COSMOS) International Guidelines for Applying Noninvasive Methods to Characterize Seismic Site Conditions. He is also a member of the Board of Directors for COSMOS.

Abstract:

The main considerations for modeling seismic ground motions typically involve a trichotomy of effects that are partitioned into source, path, and site. Site conditions--often representing no more than 1% of the path from the seismic source--can strongly influence site response, thus dominate the intensity of shaking. To account for this phenomenon, the engineering community has traditionally used the index of Vs30, the time-averaged shear-wave velocity (Vs) from the surface to a depth of 30 meters. The lecture will present a review of the state-of-practice for estimating Vs30, as well as select developments for advancing measured-based Vs30 methods. The presentation will describe current practice using multiple surface-based methods to develop robust Vs profiles to determine Vs30 within 5-10% inter- and intra-method variability. Lastly, an ongoing 2 year old international effort sponsored by the Consortium of Organization for Strong Motion Observation Systems (COSMOS) to develop best practices/guidelines for using noninvasive geophysical methods when characterizing seismic site conditions will be introduced.

You are cordially welcome to attend the lecture.