Faulting parameters of earthquakes in the New Madrid, Missouri, region

Robert B. Herrmann, Charles J. Ammon

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

The advent of high-resolution digital seismic recording and advances in computer technology enable the combination of traditional regional seismic network observations with direct seismogram modeling to improve estimates of small earthquake faulting geometry, depth, and size. We illustrate a combined modeling approach using observations from three earthquakes that occurred within the environs of the New Madrid Seismic Zone: two Missouri earthquakes from September 26, 1990 and May 4, 1991; and the southern Illinois earthquake of February 5, 1994. We also re-examine the faulting geometry for two events from the 1960s that are inconsistent with the current estimate of the regional stress field. Based on direct modeling of the long-period seismograms associated with these events, we revise earlier estimates of the earthquake parameters for the March 3, 1963 and July 21, 1967 Missouri earthquakes. Comparing the new and revised results with existing earthquake mechanisms in the region, we find that tension-axes are generally aligned in a N-S to NW-SE direction, while the compression-axes trend in a NE to E direction. An interesting exception to this pattern are the March 3, 1963 and two nearby earthquakes that lie within a well-defined 30-km long left step in seismicity near New Madrid.

Original languageEnglish (US)
Pages (from-to)299-311
Number of pages13
JournalEngineering Geology
Volume46
Issue number3-4
DOIs
StatePublished - Jul 15 1997

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Geology

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