(University of Oregon, 2019-04-30) Babb, Alexander; Thomas, Amanda
Low frequency earthquakes (LFEs) are detected at depths of 16-30 km on a 150 km section of the San Andreas Fault (SAF) centered at Parkfield, CA. The LFEs are divided into 88 families based on waveform similarity. In continuous families a burst of a few LFE events recurs every few days while episodic families experience essentially quiescent periods often lasting months followed by bursts of hundreds of events over a few days. The occurrence of LFEs has also been shown to be sensitive to extremely small (~1 kPa) tidal stress perturbations. However, the clustered nature of LFE occurrence could potentially bias estimates of tidal sensitivity. Here we re-evaluate the tidal sensitivity of LFE families on the deep San Andreas using a declustered catalog. Declustered LFE families are still highly sensitive to primarily right-lateral shear stress (RLSS) and to a lesser extent fault normal stress (FNS).
