DATABASE OF GEOTECHNICAL SHEAR-WAVE SEISMIC-VELOCITY PROFILE MEASUREMENTS FOR CALIFORNIA AND NEVADA

The time-averaged seismic shear-wave velocity from the surface to 30 m (100 ft) depth, defined in the Building Code as Vs100, is in the United States one of the principal determinants of earthquake site-hazard classification. Over the past 20 years the Nevada Seismological Lab and the Applied Geophysics class at the University of Nevada, Reno; Optim Earth; and Terean™ have made shallow (<1 km deep) shear-wave velocity measurements at 571 sites in Nevada and California, and 40 in New Zealand, using refraction microtremor (a.k.a. ReMi) array measurements. The US Geological Survey sponsored many of these measurements, calibrating stations in regional earthquake-monitoring and strong-motion networks. The link to the database is https://sites.google.com/view/vs-profile-archive; also accessible from https://Louie.pub. Earthquake-monitoring stations are often on bedrock; the database also includes the results of transects across the Reno, Las Vegas, and Los Angeles urban basins that are mostly deep soil sites. Each file in the database is a self-explanatory, plain-text list of the data and results from the measurement. Measurements made at slightly different array locations, at different times, and by different interpreters produced multiple files for some sites. The multiple results express both the aleatory variation of velocity in the ground, and the epistemic variability of the measurement technique. Each measurement file includes array-location data, a summary Vs30 value, and a modeled shear-wave-velocity-versus-depth profile. Efforts are mostly complete to add the picked slowness-frequency image and the picked fundamental-mode Rayleigh-wave dispersion-curve data to each file. These archives give additional details on measurements found in the US Geological Survey's Vs30 compilations at https://www.sciencebase.gov/catalog/item/6183f02cd34ec04fc9bf7f8f and https://earthquake.usgs.gov/data/vs30/us/ . An additional 10,722 Vs30 measurements in Las Vegas and Clark County, Nevada are available from the Clark County GIS system at http://gisgate.co.clark.nv.us/ow/ (select the "Seismic" map type).