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Constraining the source location of the 30 May 2015 ( M w 7.9) Bonin deep‐focus earthquake using seismogram envelopes of high‐frequency P waveforms: Occurrence of deep‐focus earthquake at the bottom of a subducting slab
Author(s) -
Takemura Shunsuke,
Maeda Takuto,
Furumura Takashi,
Obara Kazushige
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068437
Subject(s) - seismogram , seismology , geology , deep focus earthquake , aftershock , coda , p wave , waveform , focus (optics) , slab , pulse (music) , seismic wave , s wave , geophysics , subduction , physics , optics , tectonics , medicine , quantum mechanics , voltage , detector , cardiology , atrial fibrillation
In this study, the source location of the 30 May 2015 ( M w 7.9) deep‐focus Bonin earthquake was constrained using P wave seismograms recorded across Japan. We focus on propagation characteristics of high‐frequency P wave. Deep‐focus intraslab earthquakes typically show spindle‐shaped seismogram envelopes with peak delays of several seconds and subsequent long‐duration coda waves; however, both the main shock and aftershock of the 2015 Bonin event exhibited pulse‐like P wave propagations with high apparent velocities (~12.2 km/s). Such P wave propagation features were reproduced by finite‐difference method simulations of seismic wave propagation in the case of slab‐bottom source. The pulse‐like P wave seismogram envelopes observed from the 2015 Bonin earthquake show that its source was located at the bottom of the Pacific slab at a depth of ~680 km, rather than within its middle or upper regions.