Combined high-resolution topographic analysis and paleoshoreline dating reveal spatio-temporal variability in slip rates on low-strain-rate normal faults
Department or Administrative Unit
In the northwestern Basin and Range of the western US, normal fault scarps line many of the range-fronts and pluvial lakes filled many of the valleys during the Pleistocene. Lake paleoshorelines provide a paleohorizontal datum from which to
assess crustal deformation. Often these shorelines are capped by carbonate tufa. Detailed mapping of fault scarps and paleoshorelines along with radiocarbon geochronology provides insight into the distribution and timing of slip along faults, such as the Surprise Valley fault (SVF) in California and the Winter Rim fault system (WRF) in Oregon. Our analyses reveal that slip rates vary by as much as 4x along the length of the SVF over the last 25 ky, and that segments of the WRF that are optimally-oriented for activation under the prevailing stress regime have accumulated twice as much offset as non-optimally-oriented segments. Our results highlight significant spatio-temporal variability in slip rates.
Egger, A. E., Marion, B., & Hall, J. (2017). Combined high-resolution topographic analysis and paleoshoreline dating reveal spatio-temporal variability in slip rates on low-strain-rate normal faults. 8th International INQUA Meeting on Paleoseismology, Active Tectonics and Archeoseismology, 112-115.
8th International INQUA Meeting on Paleoseismology, Active Tectonics and Archeoseismology
© Institute of Geological and Nuclear Sciences Limited, 2017