TY  - JOUR
A1  - Letort, Jean
A1  - Retailleau, Lise
A1  - Boue, Pierre
A1  - Radiguet, Mathilde
A1  - Gardonio, Blandine
A1  - Cotton, Fabrice Pierre
A1  - Campillo, Michel
T1  - Lateral variations of the Guerrero-Oaxaca subduction zone (Mexico) derived from weak seismicity (M(b)3.5+) detected on a single array at teleseismic distance
JF  - Geophysical journal international
N2  - Detections of pP and sP phase arrivals (the so-called depth phases) at teleseismic distance provide one of the best ways to estimate earthquake focal depth, as the P-pP and the P-sP delays are strongly dependent on the depth. Based on a new processing workflow and using a single seismic array at teleseismic distance, we can estimate the depth of clusters of small events down to magnitude M-b 3.5. Our method provides a direct view of the relative variations of the seismicity depth from an active area. This study focuses on the application of this new methodology to study the lateral variations of the Guerrero subduction zone (Mexico) using the Eielson seismic array in Alaska (USA). After denoising the signals, 1232 M-b 3.5 + events were detected, with clear P, pP, sP and PcP arrivals. A high-resolution view of the lateral variations of the depth of the seismicity of the Guerero-Oaxaca area is thus obtained. The seismicity is shown to be mainly clustered along the interface, coherently following the geometry of the plate as constrained by the receiver-function analysis along the Meso America Subduction Experiment profile. From this study, the hypothesis of tears on the western part of Guerrero and the eastern part of Oaxaca are strongly confirmed by dramatic lateral changes in the depth of the earthquake clusters. The presence of these two tears might explain the observed lateral variations in seismicity, which is correlated with the boundaries of the slow slip events.
KW  - North America
KW  - Time-series analysis
KW  - Body waves
KW  - Earthquake source observations
KW  - Seismicity and tectonics
Y1  - 2018
U6  - https://doi.org/10.1093/gji/ggy035
SN  - 0956-540X
SN  - 1365-246X
VL  - 213
IS  - 2
SP  - 1002
EP  - 1012
PB  - Oxford Univ. Press
CY  - Oxford
ER  -