Seismic Evidence of Quaternary Faulting in the Benton Hills Area, Southeast Missouri

Abstract

Two reflection seismic profiles at English Hill, across the southern edge of the Benton Hills escarpment, southeast Missouri, establish that geologic structures at English Hill are of tectonic origin. The lowland area to the south of the escarpment is relatively undisturbed. The geology at English Hill is structurally complex, and reflection seismic and geologic data indicate extensive and episodic faulting of Paleozoic, Cretaceous, Tertiary, and Quaternary strata. The individual faults have near-vertical fault surfaces with maximum vertical separations on the order of 15 m. They appear to be clustered in north-northeast trending zones that essentially parallel one of the dominant Benton Hills structural trends. These observations suggest that previously mapped Quaternary faults at English Hill are deep-seated and tectonic in origin. This paper documents recent faulting at English Hill and is the first time late Quaternary, surface-rupture faulting has been recognized in the middle Mississippi River Valley region outside of the New Madrid seismic zone. This has important implications for earthquake assessment in the midcontinent.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Crustal Structure; Faulting; Neotectonics; Quaternary; Seismic Survey; Tectonics; USA, Missouri, Benton Hills

Geographic Coverage

Southeast Missouri

International Standard Serial Number (ISSN)

0012-8287

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1997 Seismological Society of America, All rights reserved.

Publication Date

01 Jul 1997

Link to Full Text

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