Can the Liquiñe-Ofqui System Fault Generates Slow Slip Signatures?

The Liquiñe-Ofqui Fault zone (LOFZ) is a trench parallel dextral strike-slip fault system that extends more than 1000 km from 38° to 47°S in southern Chile. The LOFZ has been formed from the oblique subduction that exists between the Nazca and South American plates. Between January 2007 and February 2008, an intense seismic sequence was associated to the LOFZ, being the earthquakes of April 2 M_w 6.1 and April 21 M_w 6.2 its main events. The latest earthquakes produced a landslide that triggered a local tsunami generating the death of 10 people. Since 2011, the National Seismological Center (CSN) and the SERNAGEOMIN deployed a network of stations in the area in order to monitor the seismic behavior of the LOFZ. The network is composed of 21 broadband stations that record continuous ground motion. We used these data to analyze a new seismic sequence occurred between May and June 2018. We identified and localized 142 shallow crustal events with depths no greater than 20 km and M_l<3.5. The events were concentrated in one of the branches of the LOFZ and were characterized by the occurrence of repeating earthquakes. In addition, using the envelope technique, we were able to detect and localize episodes of non-volcanic tremors (NVT) with duration from minutes to hours. We propose that LOFZ is able to generate regular earthquakes and slow slip signatures such as the San Andreas Fault near Parkfield and the Alpine Fault in New Zealand. The study and continuous monitoring of LOFZ will allow us to better understand the seismic behavior of this large and complex crustal system.