The Olmsted fault zone, southernmost Illinois: A key to understanding seismic hazard in the northern new Madrid seismic zone

C. E. Bexfield, John H. McBride, A. J.M. Pugin, W. J. Nelson, Timothy H Larson, Steve L Sargent

Research output: Contribution to journalArticle

Abstract

Geological deformation in the northern New Madrid seismic zone, near Olmsted, Illinois (USA), is analyzed using integrated compressional-wave (P) and horizontally polarized-wave (SH) seismic reflection and regional and dedicated borehole information. Seismic hazards are of special concern because of strategic facilities (e.g., lock and dam sites and chemical plants on the Ohio River near its confluence with the Mississippi River) and because of alluvial soils subject to high amplification of earthquake shock. We use an integrated approach starting with lower resolution, but deeper penetration, P-wave reflection profiles to identify displacement of Paleozoic bedrock. Higher resolution, but shallower penetration, SH-wave images show deformation that has propagated upward from bedrock faults into Pleistocene loess. We have mapped an intricate zone more than 8 km wide of high-angle faults in Mississippi embayment sediments localized over Paleozoic bedrock faults that trend north to northeast, parallel to the Ohio River. These faults align with the pattern of epicenters in the New Madrid seismic zone. Normal and reverse offsets along with positive flower structures imply a component of strike-slip; the current stress regime favors right-lateral slip on northeast-trending faults. The largest fault, the Olmsted fault, underwent principal displacement near the end of the Cretaceous Period 65 to 70 million years ago. Strata of this age (dated via fossil pollen) thicken greatly on the downthrown side of the Olmsted fault into a locally subsiding basin. Small offsets of Tertiary and Quaternary strata are evident on high-resolution SH-wave seismic profiles. Our results imply recent reactivation and possible future seismic activity in a critical area of the New Madrid seismic zone. This integrated approach provides a strategy for evaluating shallow seismic hazard-related targets for engineering concerns.

Original languageEnglish (US)
Pages (from-to)179-201
Number of pages23
JournalEngineering Geology
Volume81
Issue number2
DOIs
StatePublished - Oct 1 2005

Fingerprint

seismic zone
seismic hazard
fault zone
Hazards
Seismic waves
Rivers
SH-wave
Chemical plants
Boreholes
bedrock
Dams
Amplification
Earthquakes
Sediments
integrated approach
P-wave
Soils
penetration
Paleozoic
river

Keywords

  • New Madrid seismic zone
  • Seismic hazard faults
  • Seismic reflection method

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Geology

Cite this

The Olmsted fault zone, southernmost Illinois : A key to understanding seismic hazard in the northern new Madrid seismic zone. / Bexfield, C. E.; McBride, John H.; Pugin, A. J.M.; Nelson, W. J.; Larson, Timothy H; Sargent, Steve L.

In: Engineering Geology, Vol. 81, No. 2, 01.10.2005, p. 179-201.

Research output: Contribution to journalArticle

@article{80667fc13016475d8ba1d33abee45101,
title = "The Olmsted fault zone, southernmost Illinois: A key to understanding seismic hazard in the northern new Madrid seismic zone",
abstract = "Geological deformation in the northern New Madrid seismic zone, near Olmsted, Illinois (USA), is analyzed using integrated compressional-wave (P) and horizontally polarized-wave (SH) seismic reflection and regional and dedicated borehole information. Seismic hazards are of special concern because of strategic facilities (e.g., lock and dam sites and chemical plants on the Ohio River near its confluence with the Mississippi River) and because of alluvial soils subject to high amplification of earthquake shock. We use an integrated approach starting with lower resolution, but deeper penetration, P-wave reflection profiles to identify displacement of Paleozoic bedrock. Higher resolution, but shallower penetration, SH-wave images show deformation that has propagated upward from bedrock faults into Pleistocene loess. We have mapped an intricate zone more than 8 km wide of high-angle faults in Mississippi embayment sediments localized over Paleozoic bedrock faults that trend north to northeast, parallel to the Ohio River. These faults align with the pattern of epicenters in the New Madrid seismic zone. Normal and reverse offsets along with positive flower structures imply a component of strike-slip; the current stress regime favors right-lateral slip on northeast-trending faults. The largest fault, the Olmsted fault, underwent principal displacement near the end of the Cretaceous Period 65 to 70 million years ago. Strata of this age (dated via fossil pollen) thicken greatly on the downthrown side of the Olmsted fault into a locally subsiding basin. Small offsets of Tertiary and Quaternary strata are evident on high-resolution SH-wave seismic profiles. Our results imply recent reactivation and possible future seismic activity in a critical area of the New Madrid seismic zone. This integrated approach provides a strategy for evaluating shallow seismic hazard-related targets for engineering concerns.",
keywords = "New Madrid seismic zone, Seismic hazard faults, Seismic reflection method",
author = "Bexfield, {C. E.} and McBride, {John H.} and Pugin, {A. J.M.} and Nelson, {W. J.} and Larson, {Timothy H} and Sargent, {Steve L}",
year = "2005",
month = "10",
day = "1",
doi = "10.1016/j.enggeo.2005.07.003",
language = "English (US)",
volume = "81",
pages = "179--201",
journal = "Engineering Geology",
issn = "0013-7952",
publisher = "Elsevier",
number = "2",

}

TY - JOUR

T1 - The Olmsted fault zone, southernmost Illinois

T2 - A key to understanding seismic hazard in the northern new Madrid seismic zone

AU - Bexfield, C. E.

AU - McBride, John H.

AU - Pugin, A. J.M.

AU - Nelson, W. J.

AU - Larson, Timothy H

AU - Sargent, Steve L

PY - 2005/10/1

Y1 - 2005/10/1

N2 - Geological deformation in the northern New Madrid seismic zone, near Olmsted, Illinois (USA), is analyzed using integrated compressional-wave (P) and horizontally polarized-wave (SH) seismic reflection and regional and dedicated borehole information. Seismic hazards are of special concern because of strategic facilities (e.g., lock and dam sites and chemical plants on the Ohio River near its confluence with the Mississippi River) and because of alluvial soils subject to high amplification of earthquake shock. We use an integrated approach starting with lower resolution, but deeper penetration, P-wave reflection profiles to identify displacement of Paleozoic bedrock. Higher resolution, but shallower penetration, SH-wave images show deformation that has propagated upward from bedrock faults into Pleistocene loess. We have mapped an intricate zone more than 8 km wide of high-angle faults in Mississippi embayment sediments localized over Paleozoic bedrock faults that trend north to northeast, parallel to the Ohio River. These faults align with the pattern of epicenters in the New Madrid seismic zone. Normal and reverse offsets along with positive flower structures imply a component of strike-slip; the current stress regime favors right-lateral slip on northeast-trending faults. The largest fault, the Olmsted fault, underwent principal displacement near the end of the Cretaceous Period 65 to 70 million years ago. Strata of this age (dated via fossil pollen) thicken greatly on the downthrown side of the Olmsted fault into a locally subsiding basin. Small offsets of Tertiary and Quaternary strata are evident on high-resolution SH-wave seismic profiles. Our results imply recent reactivation and possible future seismic activity in a critical area of the New Madrid seismic zone. This integrated approach provides a strategy for evaluating shallow seismic hazard-related targets for engineering concerns.

AB - Geological deformation in the northern New Madrid seismic zone, near Olmsted, Illinois (USA), is analyzed using integrated compressional-wave (P) and horizontally polarized-wave (SH) seismic reflection and regional and dedicated borehole information. Seismic hazards are of special concern because of strategic facilities (e.g., lock and dam sites and chemical plants on the Ohio River near its confluence with the Mississippi River) and because of alluvial soils subject to high amplification of earthquake shock. We use an integrated approach starting with lower resolution, but deeper penetration, P-wave reflection profiles to identify displacement of Paleozoic bedrock. Higher resolution, but shallower penetration, SH-wave images show deformation that has propagated upward from bedrock faults into Pleistocene loess. We have mapped an intricate zone more than 8 km wide of high-angle faults in Mississippi embayment sediments localized over Paleozoic bedrock faults that trend north to northeast, parallel to the Ohio River. These faults align with the pattern of epicenters in the New Madrid seismic zone. Normal and reverse offsets along with positive flower structures imply a component of strike-slip; the current stress regime favors right-lateral slip on northeast-trending faults. The largest fault, the Olmsted fault, underwent principal displacement near the end of the Cretaceous Period 65 to 70 million years ago. Strata of this age (dated via fossil pollen) thicken greatly on the downthrown side of the Olmsted fault into a locally subsiding basin. Small offsets of Tertiary and Quaternary strata are evident on high-resolution SH-wave seismic profiles. Our results imply recent reactivation and possible future seismic activity in a critical area of the New Madrid seismic zone. This integrated approach provides a strategy for evaluating shallow seismic hazard-related targets for engineering concerns.

KW - New Madrid seismic zone

KW - Seismic hazard faults

KW - Seismic reflection method

UR - http://www.scopus.com/inward/record.url?scp=27644478798&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27644478798&partnerID=8YFLogxK

U2 - 10.1016/j.enggeo.2005.07.003

DO - 10.1016/j.enggeo.2005.07.003

M3 - Article

AN - SCOPUS:27644478798

VL - 81

SP - 179

EP - 201

JO - Engineering Geology

JF - Engineering Geology

SN - 0013-7952

IS - 2

ER -