← Back to Sessions

Coupling Between the Northern and Southern Central San Andreas Fault via Triggered Creep

Session: Effects and Uses of Aseismic Deformation and Fault Creep in Seismic Hazard and Warning

Type: Oral

Date: 4/20/2021

Presentation Time: 06:00 PM Pacific

Description: 

Episodic creep is one of the most poorly understood aspects of fault motion. In particular, the interaction between creep events and earthquakes at the regional scale has implications for earthquake cycles, yet few examples of such interaction have been found on continental faults. Here we report creep triggering along the northern edge of the creeping section of the San Andreas fault following the 2003 San Simeon Mw 6.5 and 2004 Parkfield Mw 6.0 earthquakes. Following the San Simeon earthquake, we observe a delayed creep event on two creepmeters, as well as a larger one-day delayed event beginning at depth on SJT strainmeter and continuing on the nearby San Juan Bautista creepmeter (XSJ). Following the Parkfield earthquake, the XSJ creepmeter and SJT strainmeter again record a delayed, creep event. In addition, the regional earthquakes produced long-term creep rate changes. After the San Simeon earthquake, the average slip rate at XSJ increased from 10 mm/yr to 30 mm/yr, and returned to 10 mm/yr after the Parkfield earthquake. The combination of the creep event and rate change data indicate that triggering couples the northern San Andreas Fault to both the southern locked section and other regional faults.

Presenting Author: Brenton W. Hirao

Student Presenter: Yes

Authors