Logs and scarp data from a paleoseismic investigation of the Surprise Valley fault zone, Modoc County, California

Scientific Investigations Map 2983
By: , and 



This report contains field and laboratory data from a paleoseismic study of the Surprise Valley fault zone near Cedarville, California. The 85-km-long Surprise Valley fault zone forms the western active margin of the Basin and Range province in northeastern California. The down-to-the-east normal fault is marked by Holocene fault scarps along most of its length, from Fort Bidwell on the north to near the southern end of Surprise Valley. We studied the central section of the fault to determine ages of paleoearthquakes and to better constrain late Quaternary slip rates, which we hope to compare to deformation rates derived from a recently established geodetic network in the region (Hammond and Thatcher, 2005; 2007). We excavated a trench in June 2005 across a prominent fault scarp on pluvial Lake Surprise deltaic sediments near the mouth of Cooks Canyon, 4 km north of Cedarville. This site was chosen because of the presence of a well-preserved fault scarp and its development on lacustrine deposits thought to be suitable for luminescence dating. We also logged a natural exposure of the fault in similar deltaic sediments near the mouth of Steamboat Canyon, 11 km south of Cedarville, to better understand the along-strike extent of surface ruptures. The purpose of this report is to present photomosaics, trench, drill hole, and stream exposure logs; scarp profiles; and fault slip, tephrochronologic, radiocarbon, luminescence, and unit description data obtained during this investigation. We do not attempt to use the data presented herein to construct a paleoseismic history of this part of the Surprise Valley fault zone; that history will be the subject of a future report.

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Publication type Report
Publication Subtype USGS Numbered Series
Title Logs and scarp data from a paleoseismic investigation of the Surprise Valley fault zone, Modoc County, California
Series title Scientific Investigations Map
Series number 2983
DOI 10.3133/sim2983
Edition Version 1.1, Revised Jul 2008
Year Published 2007
Language English
Publisher Geological Survey (U.S.)
Contributing office(s) U.S. Geological Survey
Description 2 Plates: 64 x 36 inches and 68 x 36 inches
Country United States
State California
County Modoc County
Other Geospatial Surprise Valley fault zone
Additional Online Files (Y/N) Y
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