[J06-1] The spectrum of fault-zone deformation processes (from slow slip to earthquake) I

[J06-1-04] Insights into the Causal Relationship between Slow Slip Events and Tectonic Tremors in Guerrero, Mexico

^○Carlos Villafuerte, Victor Cruz-Atienza (Instituto de Geofisica, UNAM, Mexico)

Similar to other subduction zones, tectonic tremors (TT) and slow slip events (SSE) take place along the deep segment of the plate interface in Guerrero. However, their interaction in this region is not as clear as the Episodic Tremor and Slip observed in Cascadia and Japan. In this study we provide insights into such interaction analyzing the evolution of the deformation fields induced by the long-term 2006 SSE together with independent new locations of TTs and low-frequency earthquakes (LFE). Unlike previous studies we find that the SSE slip rate is the parameter that modulates the TT and LFE occurrence rate in the whole tremor region. This means that the causal relationship between the SSE and the TT activity directly depends on the stressing rate history of the locked asperities that is modulated by the SSE slip rate. We have estimated that the frictional strength of the asperities radiating tremor downdip in the Sweet Spot is around 32 kPa, which is ~2.2 times smaller than the corresponding value updip in the Transient Zone, partly explaining the overwhelming tremor activity of the Sweet Spot despite that the slow slip there is almost three times smaller. Based on the LFEs occurrence rate history during the inter-SSE period we determined that the short-term SSEs in Guerrero take place further downdip (about 35 km) than previously estimated, with maximum slip of about 8 mm overlapping the Sweet Spot. This new model features a continuum of slow slip extending across the entire tremor region of Guerrero.