Reproducibility of San Andreas Fault Slip Rate Measurements at Wallace Creek in the Carrizo Plain, CA

Lisa Grant Ludwig, Sinan O. Akciz, J Ramon Arrowsmith, & J. Barrett Salisbury

Published January 30, 2019, SCEC Contribution #8145

Reproducibility of results from scientific studies is rarely demonstrated outside the laboratory. Measurements of fault slip rate underpin scientific models of active faulting and seismic hazard assessments widely used for policymaking and risk mitigation. We replicated a highly referenced study that measured the slip rate as 33.9 ± 2.9 mm/yr along the San Andreas fault (SAF) over the past ~3,700 years at Wallace Creek (WC) in the Carrizo Plain National Monument, USA. Our study was motivated by new data that suggest significant changes in slip rate over the past few millennia. We find that the late Holocene slip rate of the SAF, a key indicator of seismic hazard, is reproducible within measurement uncertainty. Geologic slip rate determinations are relatively insensitive to short term fluctuations and thus should be reproducible if the time interval of measurement is much greater than the average rupture interval.

Citation
Grant Ludwig, L., Akciz, S. O., Arrowsmith, J., & Salisbury, J. (2019). Reproducibility of San Andreas Fault Slip Rate Measurements at Wallace Creek in the Carrizo Plain, CA. Earth and Space Science, 6(1), 156-165. doi: 10.1029/2017EA000360.