Universality of slow earthquakes in the very low frequency band
Deep tectonic tremors have been observed together with signals in the very low frequency (VLF) band from 0.02 to 0.05 Hz, which have been identified as VLF events in limited regions of subduction zones. By stacking broadband seismograms relative to the timing of tremors, we have detected similar sig...
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Published in | Geophysical research letters Vol. 41; no. 8; pp. 2786 - 2793 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Washington
Blackwell Publishing Ltd
28.04.2014
John Wiley & Sons, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Deep tectonic tremors have been observed together with signals in the very low frequency (VLF) band from 0.02 to 0.05 Hz, which have been identified as VLF events in limited regions of subduction zones. By stacking broadband seismograms relative to the timing of tremors, we have detected similar signals in all regions where tremors occur in western Japan. These signals are inverted to obtain the moment tensor, and the fault‐normal and slip vectors are generally consistent with the geometry of the plate interface and the direction of plate motion. Therefore, these signals are probably radiated by shear slip on the plate interface. The ratio between the seismic energy rate estimated from the tremors and seismic moment rate in the VLF band is almost proportional, with a proportionality constant (i.e., scaled energy) of around 5 × 10−10. The spatial distribution of scaled energy may reflect spatial variations in the frequency‐dependent characteristics of slow deformation.
Key Points
Detection of hidden signals in the VLF band by stacking broadband tremor signalsSpatial distribution of moment tensor for all tremor regions in western JapanProportionality between tremor energy and VLF seismic moment |
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Bibliography: | JSPS KAKENHI - No. 23244090 ark:/67375/WNG-WRX0C7FB-F ReadmeFigures S1-S6 and Table S1 istex:88A76922F2C3A7F75CD26A80380D1CECA741E850 MEXT KAKENHI - No. 21107007 ArticleID:GRL51628 This article was corrected on 8 SEP 2014. See the end of the full text for details. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1002/2014GL059712 |