Shallow P- and S-wave velocities and site resonances in the St. Louis region, Missouri-Illinois

Earthquake Spectra
By: , and 

Links

Abstract

As part of the seismic hazard-mapping efforts in the St. Louis metropolitan area we determined the compressional and shear-wave velocities (Vp and Vs) to about a 40-m depth at 17 locations in this area. The Vs measurements were made using high-resolution seismic refraction and reflection methods. We find a clear difference in the Vs profiles between sites located on the river floodplains and those located in the upland urban areas of St. Louis. Vs30 (average Vs to 30-m depth) values in floodplain areas range from 200 to 290 m/s (NEHRP category D) and contrast with sites on the upland areas of St. Louis, which have Vs30 values ranging from 410 to 785 m/s (NEHRP categories C and B). The lower Vs30 values and earthquake recordings in the floodplains suggest a greater potential for stronger and more prolonged ground shaking in an earthquake. Spectral analysis of a M3.6 earthquake recorded on the St. Louis-area ANSS seismograph network indicates stronger shaking and potentially damaging S-wave resonant frequencies at NEHRP category D sites compared to ground motions at a rock site located on the Saint Louis University campus. ?? 2007, Earthquake Engineering Research Institute.
Publication type Article
Publication Subtype Journal Article
Title Shallow P- and S-wave velocities and site resonances in the St. Louis region, Missouri-Illinois
Series title Earthquake Spectra
DOI 10.1193/1.2753548
Volume 23
Issue 3
Year Published 2007
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Earthquake Spectra
First page 711
Last page 726
Google Analytic Metrics Metrics page
Additional publication details