Spatial distribution and energy release of nonvolcanic tremor at Parkfield, California

Staudenmaier, N, Edwards, B ORCID: 0000-0001-5648-8015, Tormann, T, Zechar, JD and Wiemer, S
(2016) Spatial distribution and energy release of nonvolcanic tremor at Parkfield, California. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 121 (12). pp. 8833-8854.

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Nonvolcanic tremors (NVTs) are observed in transition zones between freely slipping andlocked sections of faults and normally occur below the seismogenic zone. Based on NVT recordings in theParkfield region of the San Andreas Fault, we provide a novel approach to assess the energy release of theseevents and assign magnitudes (Me) that are compatible with size estimates of small earthquakes in the sameregion. To assess the energy magnitude of a detected tremor, we refine the estimate of its duration andperform a spectral analysis that accounts for local attenuation. For the 218 NVTs that we were able to process,we resolveMevalues in the range of 0.67 to 0.84. For events, which we could not process using the spectralanalysis technique, we propose a statistical model to estimateMevalues using observable characteristics,such as peak amplitude, spectral velocity at the source corner frequency, and duration. We furthermoreprovide seismic moment and moment magnitude estimates and calculate stress drops in a range of 3–10 kPa.As a result of our spectral analyses, wefind strong indications regarding the ongoing debate aboutpotential NVT location hypotheses: the Parkfield NVTs have a higher probability to be located in the proposedthree-dimensional cloud-like cluster than in any other suggested location distributio

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 23 Mar 2017 07:31
Last Modified: 19 Jan 2023 07:09
DOI: 10.1002/2016JB013283
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