Nonvolcanic tremor observed in the Mexican subduction zone

Nonvolcanic tremor (NVT) activity is revealed as episodes of higher spectral amplitude at 1–8 Hz in daily spectrograms from the continuous seismological records in Guerrero, Mexico. The analyzed data cover a period of 2001–2007 when in 2001–2002 a large slow slip event (SSE) had occurred in the Guerrero-Oaxaca region, and then a new large SSE occurred in 2006. The tremor burst is dominated by S-waves. More than 100 strong NVT bursts were recorded in the narrow band of ~40 × 150 km^2 to the south of Iguala City and parallel to the coastline. Depths of NVT hypocenters are mostly scattered in the continental crust between 5 and 40 km depth. Tremor activity is higher during the 2001–2002 and 2006 SSE compared with that for the “quiet” period of 2003–2005. While resistivity pattern in Guerrero does not correlate directly with the NVT distribution, gravity and magnetic anomaly modeling favors a hypothesis that the NVT is apparently related to the dehydration and serpentinization processes.

[1]  S. Sekine,et al.  Slow Earthquakes Coincident with Episodic Tremors and Slow Slip Events , 2007, Science.

[2]  利久 亀井,et al.  California Institute of Technology , 1958, Nature.

[3]  G. Beroza,et al.  Non-volcanic tremor and low-frequency earthquake swarms , 2007, Nature.

[4]  H. Hirose,et al.  Episodic slow slip events accompanied by non‐volcanic tremors in southwest Japan subduction zone , 2004 .

[5]  H. Dragert,et al.  Episodic Tremor and Slip on the Cascadia Subduction Zone: The Chatter of Silent Slip , 2003, Science.

[6]  Richard G. Gordon,et al.  Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions , 1994 .

[7]  G. Beroza,et al.  Low-frequency earthquakes in Shikoku, Japan, and their relationship to episodic tremor and slip , 2006, Nature.

[8]  R. Nadeau,et al.  Nonvolcanic Tremors Deep Beneath the San Andreas Fault , 2005, Science.

[9]  D. Comte,et al.  Seismic velocity structure of the Guerrero gap, Mexico , 2006 .

[10]  B. Valette,et al.  Locating sources of volcanic tremor and emergent events by seismic triangulation: Application to Arenal volcano, Costa Rica , 2002 .

[11]  K. Larson,et al.  The 2006 aseismic slow slip event in Guerrero, Mexico: New results from GPS , 2007 .

[12]  K. Brown,et al.  Correlated transient fluid pulsing and seismic tremor in the Costa Rica subduction zone [rapid communication] , 2005 .

[13]  P. Lomdahl,et al.  Nonvolcanic Deep Tremor Associated with Subduction in Southwest Japan Kazushige Obara , 2008 .

[14]  Kelin Wang,et al.  Spatial‐temporal patterns of seismic tremors in northern Cascadia , 2006 .

[15]  H. Hirose,et al.  Non-volcanic deep low-frequency tremors accompanying slow slips in the southwest Japan subduction zone , 2006 .

[16]  Kristine M. Larson,et al.  A large silent earthquake in the Guerrero seismic gap, Mexico , 2003 .

[17]  V. Manea,et al.  Thermal structure, coupling and metamorphism in the Mexican subduction zone beneath Guerrero , 2004 .

[18]  Fred W. Klein,et al.  User's guide to HYPOINVERSE-2000, a Fortran program to solve for earthquake locations and magnitudes , 2002 .

[19]  William J. Hinze,et al.  Magnetic anomaly map of North America , 1988 .

[20]  Herb Dragert,et al.  Automatic detection and characterization of seismic tremors in northern Cascadia , 2007 .

[21]  S. Malone,et al.  Temporal and spatial occurrence of deep non‐volcanic tremor: From Washington to northern California , 2005 .

[22]  Kazushige Obara,et al.  Nonvolcanic Deep Tremor Associated with Subduction in Southwest Japan , 2002, Science.

[23]  Akio Katsumata,et al.  Low‐frequency continuous tremor around the Moho discontinuity away from volcanoes in the southwest Japan , 2003 .

[24]  Robert W. Clayton,et al.  Seismic Structure of the Subducted Cocos Plate , 2007 .

[25]  J. Arzate,et al.  Fluid release from the subducted Cocos plate and partial melting of the crust deduced from magnetotelluric studies in southern Mexico: implications for the generation of volcanism and subduction dynamics , 2006 .