Skip to main content
U.S. flag

An official website of the United States government

Coexisting seismic behavior of transform faults revealed by high-resolution bathymetry

February 6, 2020

Transform faults are known to have anomalously low rates of seismicity, but no direct observations reveal why this is the case. We use new, autonomous underwater vehicle high-resolution seafloor mapping to image the morphology of and offsets along transform fault segments in the Gulf of California. Fault splays display a varied history of activation and deactivation of individual fault strands over time, not unlike those mapped onshore or imaged within the bathymetry of the Queen Charlotte-Fairweather and the Palos Verdes faults of offshore western Canada and Southern California. A series of six identically offset depositional fans evidence 21–23 meters of slip along the main transform fault, which could not have been produced by a single earthquake. Rather, the lack of smaller-magnitude offsets indicates synchronous deposition and an absence of multiple slope failure-inducing earthquakes, thus providing the first direct evidence that creep and earthquakes occur at different times in the slip history of a given transform fault segment.

Publication Year 2020
Title Coexisting seismic behavior of transform faults revealed by high-resolution bathymetry
DOI 10.1130/G46663.1
Authors George E. Hilley, Robert M. Sare, Felipe Aron, Curtis W Baden, Dave Caress, Christopher M. Castillo, Stephen C. Dobbs, Jared T Gooley, Samuel Johnstone, Frances Liu, Tim McHargue, Josie M Nevitt, Charles K. Paull, Lauren E. Shumaker, Miles M Traer, Holly H Young
Publication Type Article
Publication Subtype Journal Article
Series Title Geology
Index ID 70208491
Record Source USGS Publications Warehouse
USGS Organization Geosciences and Environmental Change Science Center