The New Seismological Observation System in Chile and a Real time GPS Detection of the Displacement Associated with a M=7.7 Earthquake in Chile

Abstract:

Due to the occurrence of several high-impact earthquakes in Chile within the last few years, governmental authorities decided to improve the seismic monitoring capabilities in the country. Along these lines, in 2013 the University of Chile created the National Seismological Center, an agency that is the continuation of the Seismological Service. The Seismological Center at the University of Chile has been charged with the installation and robust operation of a network which includes three types of observations: acceleration, velocity and displacement.

The complete observational system is based on the University´s backbone of more than 60 BB and strong motion instruments which include international collaborations with GeoForschungsZentrum (GFZ, Germany), Institut de Physique du Globe de Paris (IPGP, France) and Incorporated Research Institutions for Seismology (IRIS, USA). To this, 65 broadband, 65 strong-motion and 130 real-time dual-frequency GPS devices are being installed to complement the observational system. Additionally, 297 accelerometers distributed throughout the country will be connected to the main acquisition, processing and distribution system, which is also being upgraded by incorporating hardware virtualization capabilities. It is expected that most of the installation of the remote sensors is completed by the end of 2015.

The GPS instruments will be deployed mainly along the coast every 40 or 50 km. Because a robust real-time communication is mandatory from each remote site, the preferred solution is radio link to concentration nodes where the signals (NMEA, including RTX, as well as other protocols such a BINEX, RCTM) can be uploaded to microwaves links or Vsat. Thirty one GPS stations have been deployed in the country, we expect to complete 30more installations this year.

As a result of a trial experiment with RTX capabilities (clock and satellite corrections distributed via satellite) coastal horizontal displacements of up to 30 cm were observed in real time for the largest aftershock (Mw=7.7) of the April 1, Mw=8.2 earthquake in northern Chile. These signals are the example of an extraordinary tool to characterize the earthquake source within few minutes of its occurrence.