The Mt. Angel Fault is likely one of the most active faults near the Portland metropolitan area, and was probably associated with the 1993 Scotts Mills earthquake. SH-wave seismic techniques used to image the Mt. Angel Fault suggest that the fault offsets late Pleistocene gravel (∼22 to 34 ka) at several locations. Within the study area, displacement of the late Pleistocene gravel along the strike of the Mt. Angel Fault increases from no obvious displacement on the northwest to approximately 18 m on the southeast. This trend of increasing offset along the strike of the fault is paralleled by topographic and geomorphic trends. A reconnaissance geologic investigation at an anomalous bend in the Pudding River near the projected trace of the Mt. Angel Fault revealed potential tectonic deformation in sediments younger than the late Pleistocene gravel imaged by SH-wave data. The results of this study have contributed to the paleoseismic record of the Mt. Angel Fault, laid the groundwork for future geologic investigations along the Pudding River, and determined potential sites for future paleoseismic trenching investigations.
|Number of pages||13|
|State||Published - Jun 26 2003|
Bibliographical noteFunding Information:
This research is supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award number 00HQGR0009. We appreciate Mr. Paul Tice and Mr. Mike Taylor, undergraduate students from Portland State University, for helping in collecting seismic data. We thank reviewers, Dr. Ernest Hauser and one anonymous reviewer, for providing valuable comments that have helped to improve the manuscript greatly. We also thank Meg Smath of the Kentucky Geological Survey for editorial help on the manuscript. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either express or implied, of the US Government, the State of Oregon, or the Commonwealth of Kentucky.
- Mt. Angel Fault
- SH-wave reflection
- SH-wave refraction
- Seismic investigation
ASJC Scopus subject areas
- Earth-Surface Processes