Paleoseismic Results from the Christmas Canyon West Site, Central Garlock Fault, Searles Valley, California

Kyle A. Peña, Sally F. McGill, Ed J. Rhodes, James F. Dolan, Nathan D. Brown, Bryan A. Castillo, Alexandra E. Hatem, Sourav Saha, & Robert Zinke

Submitted August 15, 2019, SCEC Contribution #9831, 2019 SCEC Annual Meeting Poster #107

In this study, a paleoseismic trench with limited age constraints that was previously excavated in 1990 across the central Garlock Fault west of Christmas Canyon, in Searles Valley, California, was reopened to take advantage of new advances in luminescence dating techniques to investigate potential temporal variability in earthquake recurrence on the Garlock fault. The trench exposed interbedded alluvial sand and pebble-gravels, with well-sorted, rounded, lacustrine sand from the most recent highstand of pluvial Lake Searles present at the base of the trench. Preliminary findings suggest at least 10 surface rupturing earthquake events occurred during the 10 k.y. time period exposed in the trench. To provide age constraints on the paleo-surface-rupturing events from the new trench, we collected 54 luminescence samples and employed the feldspar single-grain post-infrared infrared stimulated luminescence dating technique. The ages indicated that 7 events have occurred in the past ~7.2 ka, with at least 3 additional events in the more poorly stratified deeper section of the trench. This suggests a recurrence interval of ~1000 years. The most recent event seen at this trench occurred less than 700-1000 years ago, and is potentially correlative with the most recent event seen at the other paleoseismic sites on the central Garlock (<500 years ago). However, the pattern of older events seen at this trench does not exactly match the pattern at other paleoseismic sites along the Garlock Fault. In particular, one or two earthquakes appear to have occurred at the Christmas Canyon West site during a previously documented seismic lull from ~2000-5000 years ago at the El Paso Peaks site, 28 km farther west along the Garlock fault.

Key Words
paleoseismology, Garlock fault, recurrence interval, Searles Valley, IRSL, luminescense

Citation
Peña, K. A., McGill, S. F., Rhodes, E. J., Dolan, J. F., Brown, N. D., Castillo, B. A., Hatem, A. E., Saha, S., & Zinke, R. (2019, 08). Paleoseismic Results from the Christmas Canyon West Site, Central Garlock Fault, Searles Valley, California. Poster Presentation at 2019 SCEC Annual Meeting.


Related Projects & Working Groups
Earthquake Geology