Estimating seismic moment magnitude (Mw) of tremor bursts in northern Cascadia: Implications for the "seismic efficiency" of episodic tremor and slip

Estimating seismic moment magnitude (Mw) of tremor bursts in northern Cascadia: Implications for the "seismic efficiency" of episodic tremor and slip

We develop a method to estimate the seismic moments of deep non‐volcanic tremor bursts observed in northern Cascadia. For each tremor burst, the maximum amplitudes at individual stations within a time window ±5 s around the predicted arrivals of the S phase are measured and compared to the maximum S...

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Bibliographic Details
Published in:Geophysical research letters Vol. 37; no. 19
Main Authors: Kao, Honn, Wang, Kelin, Dragert, Herb, Kao, Jason Y., Rogers, Garry
Format: Journal Article
Language:English
Published: Washington, DC Blackwell Publishing Ltd 01-10-2010
American Geophysical Union
John Wiley & Sons, Inc
Subjects:
Amplitudes
Bursts
Calibration
Cascadia
Consistency
Earth sciences
Earth, ocean, space
Earthquakes
episodic tremor and slip
Exact sciences and technology
moment magnitude
Plate tectonics
Seismic activity
seismic efficiency
Seismic engineering
Seismic phenomena
Seismology
Slip
Tremors
amplitude
efficiency
slip
Consistency
b value
seismic moment
synthetic seismograms
windows
earthquakes
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Summary:We develop a method to estimate the seismic moments of deep non‐volcanic tremor bursts observed in northern Cascadia. For each tremor burst, the maximum amplitudes at individual stations within a time window ±5 s around the predicted arrivals of the S phase are measured and compared to the maximum S amplitudes measured from synthetic seismograms. The proposed method is thoroughly calibrated using 464 local earthquakes and the results show excellent consistency between the reported ML and the estimated Mw. We apply the method to northern Cascadia tremors and infer that most bursts have Mw∼1.0–1.7. The corresponding b value appears to be 1, consistent with that of ordinary earthquakes but over a narrower Mw range. Comparison of cumulative tremor Mw and the Mw estimated from the accompanying slow slip suggests that the “seismic efficiency” of the Episodic Tremor and Slip (ETS) is of the order of 0.1% or less.
Bibliography:istex:876038CF51E256E1B1FA12327FF735DE87869C06
Tab-delimited Table 1.
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ArticleID:2010GL044927
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0094-8276
1944-8007
DOI:10.1029/2010GL044927