AGU: Geophysical Research Letters

 

Editors' Highlight

Nonvolcanic tremor observed in the Mexican subduction zone

Nonvolcanic tremors (NVT) are episodes of seismic radiation (mostly in the 1-10 Hz range) likely associated with aseismic slow slip events within the transition zone between the seismogenic coupled and deep free-slipping segments of a fault. NVT has been observed on the San Andreas Fault and on some subduction thrust faults in Japan, the United States, and Costa Rica. To learn more about NVT, Payero et al. (2008) studied data from a transect across a subduction zone in central Mexico that is overdue for a major earthquake and has been well monitored with Global Positioning System (GPS) networks and broadband seismic stations from the Mesoamerican Subduction Experiment (MACE). GPS data show that two large slow slip events occurred in the Guerrero-Oaxaca region, one in 2001-2002 and the other in 2006. Seismological analyses revealed that NVT activity was higher during those two slow slip events compared with that for the "quiet" period of 2003-2005. Models suggest that NVT might be related to low-temperature metamorphic processes and dehydration of the subducted oceanic crust.

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