identifier
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Davis Slough

USGS Topo Sheet: Juniper Beach

Geographic coordinates: 48°14.43' N, 122°23.43' W

Paleoseismic record: Based on very limited reconnaissance, this site is unlikely to have preserved a record of recognizable paleoseismic events.

Setting: Davis Slough lies on the west edge of a large area of marshy lowland that connects Camano Island with the mainland. Channels of the Skagit delta and the delta of the Sillaguamish River converge about 1 km to the east. The higher areas of this deltaic lowland are diked.

Stratigraphic description: Three gouge cores (2.5-cm-diameter) were examined in an undiked area of Distichlis marsh on the east edge of the slough north of the highway. The cores showed 2-10 cm of muddy peat over 10-40 cm of peaty mud over 80-100 cm of clayey silt; all contacts were gradational.

Paleontology/Paleoecology: No paleontologic work has been completed.

Geologic interpretation: This site is in a complex delta environment characterized by migrating river channels with rapid erosion and deposition during river floods. Most of the area is diked and fringing marshes seaward of dikes may have developed since the dikes were built. Lithologic changes in cores produced by coseismic land-level changes and tsunamis would be difficult to distinguish from changes produced by floods and storms, especially under drained and cultivated land. However, paleoliquefaction features might be found in exposures along river channels and canals in this area.

Date of last work at site: September 1997

Status of work: No additional work is planned.

Published information on this site: None

Investigators: A. Nelson

Please use the following format in citing information from this page:

Nelson, A.R., Davis Slough, in Bucknam, R.C., compiler, 1999, Atlas of reconnaissance data from paleoseismic studies in the Puget Sound region, Washington: U.S. Geological Survey Web Page, http://earthquake.usgs.gov/regional/pacnw/paleo/atlas.html.

This URL is: http://earthquake.usgs.gov/regional/pacnw/paleo/reports/davisslo.htm
Modified July 29, 2002 by Susan Rhea