HR: 0800h
AN: S51A-0216    [Abstracts]
TI: ShakeMaps at the Swiss Seismological Service: Current Status, Innovations, and Outlook
AU: Wiemer, S B
EM: stefan.wiemer@sed.ethz.ch
AF: Swiss Seismological Service ETH Zurich, Schaffmattstrasse 30, Zurich, CH-8093, Switzerland
AU: * Cua, G B
EM: georgia.cua@sed.ethz.ch
AF: Swiss Seismological Service ETH Zurich, Schaffmattstrasse 30, Zurich, CH-8093, Switzerland
AU: Kaestli, P
EM: philipp.kaestli@sed.ethz.ch
AF: Swiss Seismological Service ETH Zurich, Schaffmattstrasse 30, Zurich, CH-8093, Switzerland
AU: Clinton, J
EM: john.clinton@sed.ethz.ch
AF: Swiss Seismological Service ETH Zurich, Schaffmattstrasse 30, Zurich, CH-8093, Switzerland
AU: Faeh, D
EM: donat.faeh@sed.ethz.ch
AF: Swiss Seismological Service ETH Zurich, Schaffmattstrasse 30, Zurich, CH-8093, Switzerland
AU: Maraini, S
EM: silvio.maraini@sed.ethz.ch
AF: Swiss Seismological Service ETH Zurich, Schaffmattstrasse 30, Zurich, CH-8093, Switzerland
AU: Giardini, D
EM: domenico.giardini@sed.ethz.ch
AF: Swiss Seismological Service ETH Zurich, Schaffmattstrasse 30, Zurich, CH-8093, Switzerland
AB: The ShakeMap-related efforts at the Swiss Seismological Service (SED) are motivated by the desire for improved emergency response and information dissemination following a large earthquake. The SED implementation approach has evolved over the years from developing in-house "ShakeMap"-type software to that of customizing the USGS ShakeMap codes to Swiss conditions. As part of efforts to calibrate the Swiss ShakeMap system, we have undertaken the following: 1) We use recordings from small-to-moderate Swiss earthquakes in combination with relevant strong motion data from the PEER strong motion database of crustal earthquakes to develop attenuation relationships for PGA, PGV, and response spectra at 0.3, 1.0, and 3.0 second periods valid in the magnitude range 2.5 &<& M &<& 8 using the Cua and Heaton (2007) approach. Aside from their applications in the ShakeMap system, these equations can be used to quantify the similarities (and differences) of average ground motion characteristics between southern California and Switzerland, and provide additional insight into the question of whether attenuation relationships derived from a particular region are transportable to other regions of the same tectonic setting. 2) The USGS ShakeMap system uses a uniform grid of estimated Vs30 (average shear wave velocity in the upper 30 meters) to characterize site amplification. However, Kästli and Fäh (1st European Conference on Earthquake Engineering and Seismology, 2006) have suggested that using geotechnical characteristics such as Vs30 are not as effective in predicting site amplification in Switzerland, due to its heterogeneous geology and small-scale structures, than in other regions with more homogenous sedimentary basins. We explore the use of intensity-based amplification factors derived from an extensive Swiss database of macroseismic intensity observations in characterizing site amplification. We use the Kästli and Fäh (2006) ground motion to intensity relationship to convert intensity amplification factors into "equivalent Vs30" values, and using these as inputs to our ShakeMap system. We evaluate the effectiveness of these approaches by comparing the ShakeMap-estimated instrumental intensities from a suite of well-recorded M&>&3 over the past 10 years with the macroseismic intensity reports from these events.
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2007 Fall Meeting