SCEC InstaNET News
	New Basin Depth and Soil Velocity interactive Tools

Two new web services based on data from the SCEC Phase III report are now available. For a non-technical description of the SCEC Phase III report and associated technical resources, visit http://www.scec.org/phase3. One service allows visitors to the website to find basin depths in the Los Angeles area using one of the three methods: selecting from named locations (cities, airports, colleges, etc.); entering longitude and latitude values in a text box; and clicking on a map (shown below) of the greater Los Angeles Region. Here, as elsewhere in the SCEC Phase III report, basin depth is defined as the depth to the 2.5 km/sec shear-wave velocity isosurface in the SCEC 3D velocity model of Magistrale, et al. (2000). Basin depth is one of two factors that have been studied to determine how basin structure amplifies seismic waves. To use the service, go to http://www.scec.org:8081/examples/servlet/BasinDepthServlet The newest service allows visitors to find the average S-wave velocity in the upper 30 meters of the ground for points in the Los Angeles area with the same three methods described above (the map is shown below). The velocity values are based on the classification map developed by the California Division of Mines and Geology (CDMG) and published by Wills and others in the SCEC Phase III report. The servlet uses a discretized version of the original map (with 400 meter spacing) and uses bilinear interpolation to compute the velocity between points. Surface velocity is a second factor that has a significant amplification effect on seismic waves. To use the service, go to http://www.scec.org:8081/examples/servlet/Vs30Servlet

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