A 15 year catalog of more than 1 million low‐frequency earthquakes: Tracking tremor and slip along the deep San Andreas Fault. Issue 5 (13th May 2017)

• Record Type: Journal Article
• Authors: Shelly, David R.
• Is Part Of: Journal of geophysical research. Volume 122:Issue 5(2017)
• Page Start: 3739
• Page End: 3753
• Publication Date: 2017-05-13
• Subjects: San Andreas Fault -- low‐frequency earthquakes -- tremor -- Parkfield -- slow slip; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1002/2017JB014047
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: Low‐frequency earthquakes (LFEs) are small, rapidly recurring slip events that occur on the deep extensions of some major faults. Their collective activation is often observed as a semicontinuous signal known as tectonic (or nonvolcanic) tremor. This manuscript presents a catalog of more than 1 million LFEs detected along the central San Andreas Fault from 2001 to 2016. These events have been detected via a multichannel matched‐filter search, cross‐correlating waveform templates representing 88 different LFE families with continuous seismic data. Together, these source locations span nearly 150 km along the central San Andreas Fault, ranging in depth from ~16 to 30 km. This accumulating catalog has been the source for numerous studies examining the behavior of these LFE sources and the inferred slip behavior of the deep fault. The relatively high temporal and spatial resolutions of the catalog have provided new insights into properties such as tremor migration, recurrence, and triggering by static and dynamic stress perturbations. Collectively, these characteristics are inferred to reflect a very weak fault likely under near‐lithostatic fluid pressure, yet the physical processes controlling the stuttering rupture observed as tremor and LFE signals remain poorly understood. This paper aims to document the LFE catalog assembly process and associated caveats, while also updating earlier observations and inferred physical constraints. The catalog itself accompanies this manuscript as part of the electronic supplement, with the goal of providing a useful resource for continued future investigations. Key Points: This manuscript presents a low‐frequency earthquake catalog for the central San Andreas Fault, with detailed methods and associated caveats These LFEs, presented in 88 families, demonstrate complex slip on the deep extension of the fault, which is documented here for 2001–2016 The LFE catalog is published here in its entirety as part of the electronic supplement