Nonvolcanic tremor observed in the Mexican subduction zone

Abstract

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 km2 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.

Non-volcanic Tremor: A Window into the Roots of Fault Zones

“…Obara et al, 2004) to years (Hirose et al, 1999). Strong correlations between tremor and slow slip have now been established in Cascadia and southwest Japan, and evidence is building that similar correlations may exist in Alaska (Ohta et al, 2006;Peterson and Christensen, 2009), Mexico (Payero et al, 2008), and Costa Rica (Brown et al, 2005;Schwartz et al, 2008) (Fig. 3).…”

Teleseismic constraints on the geological environment of deep episodic slow earthquakes in subduction zone forearcs: A review

“…LFEs (Frank et al, 2013(Frank et al, , 2014Husker et al, 2012;Payero et al, 2008) at a depth of 40-45 km near the plate interface (Fig. 7b, colored points).…”

Distribution of hydrous minerals in the subduction system beneath Mexico

“…Plate decoupling, as shown in GPS observations (Franco et al, 2005), may explain the lack of seismicity and compression within the overriding plate in the last $ 20 Ma based on the tectonic and magmatic episodes in central Mexico (Nieto-Samaniego et al, 2006;Morá n-Zenteno et al, 2007), despite the complete flat subduction geometry at shallow depth of 45 km Kim et al, 2010Kim et al, , 2012. Such large amount of fluid near the plate interface due to subduction related dehydration could also be an explanation for bursts of the nonvolcanic tremor within the subducted oceanic crust and lower continental crust (Payero et al, 2008) and slow slip events (Larson et al, 2007;Kostoglodov et al, 2010;Vergnolle et al, 2010;Radiguet et al, 2011). Recent studies suggest strong correlations between episodic tremor and slip (ETS) events and a low-velocity layer at the top of the subducting oceanic crust (Abers et al, 2009;Song et al, 2009;Audet et al, 2010;Kato et al, 2010).…”