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Low‐frequency earthquakes in the Mexican Sweet Spot
Author(s) -
Frank William B.,
Shapiro Nikolaï M.,
Kostoglodov Vladimir,
Husker Allen L.,
Campillo Michel,
Payero Juan S.,
Prieto Germán A.
Publication year - 2013
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/grl.50561
Subject(s) - seismogram , seismology , geology , subduction , volcano , waveform , slab , infrasound , focal mechanism , tectonics , geophysics , acoustics , telecommunications , physics , radar , computer science
We use data from the Meso‐America Subduction Experiment to detect and locate low‐frequency earthquakes (LFEs) in the Mexican subduction zone. We use visually‐identified templates to perform a network waveform correlation search that produced ~17,000 robustly detected LFEs that form 15 distinct families. Stacking an LFE family's corresponding detections results in seismograms with high signal‐to‐noise ratios and clear P and S wave arrivals; we use these travel times to locate the sources. The resulting locations superpose a previously identified region of permanent non‐volcanic tremor (NVT) activity. Husker et al. (2012) called this region a Sweet Spot, suggesting that the local conditions are adequate to continuously generate NVT. The LFE hypocenters have been located at a depth of 40–45 km in an area that is surrounding the upper slab‐plate interface. We characterize their focal mechanisms by comparing their stacked seismograms to synthetic seismograms. This analysis reveals a common low‐dipping focal mechanism.