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Holocene fault scarps near Tacoma, Washington, USA

Geology

By:
, , , , , , , and
DOI: 10.1130/G19914.1

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Abstract

Airborne laser mapping confirms that Holocene active faults traverse the Puget Sound metropolitan area, northwestern continental United States. The mapping, which detects forest-floor relief of as little as 15 cm, reveals scarps along geophysical lineaments that separate areas of Holocene uplift and subsidence. Along one such line of scarps, we found that a fault warped the ground surface between A.D. 770 and 1160. This reverse fault, which projects through Tacoma, Washington, bounds the southern and western sides of the Seattle uplift. The northern flank of the Seattle uplift is bounded by a reverse fault beneath Seattle that broke in A.D. 900-930. Observations of tectonic scarps along the Tacoma fault demonstrate that active faulting with associated surface rupture and ground motions pose a significant hazard in the Puget Sound region.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Holocene fault scarps near Tacoma, Washington, USA
Series title:
Geology
DOI:
10.1130/G19914.1
Volume
32
Issue:
1
Year Published:
2004
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geology
First page:
9
Last page:
12