thumbnail

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

Earthquake Spectra

By:
, , , and
DOI: 10.1193/1.2753548

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.

Additional Publication Details

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