IAG-IASPEI 2017

講演情報

Oral

Joint Symposia » J09. Geodesy and seismology general contributions

[J09-4] Geodesy and seismology general contributions IV

2017年8月4日(金) 08:30 〜 10:00 Room 401 (Kobe International Conference Center 4F, Room 401)

Chairs: Jan Michalek (University of Bergen) , Przemyslaw Dykowski (Institute of Geodesy and Cartography)

08:30 〜 08:45

[J09-4-01] CURRENT IMPORTANCE OF THE CHILEAN NATIONAL GEODESIC NETWORK IN A COUNTRY SUBJECT TO EARTHQUAKES

Cristian Iturriaga, Hector Parra, Carlos Prado (Instituto Geografico Militar de Chile, Santiago, Chile)

The Military Geographic Institute of Chile (IGM) is the Official Organization responsible for maintaining the National Geodesic Network (RGN) and participates in the Geocentric Reference System for the Americas (SIRGAS). At the IGM, the “SIRGAS-Chile Data Processing and Analysis Centre" manages the geodesic networks that constitute the horizontal and vertical reference systems and the permanent GNSS stations.

The IGM, together with the National Seismological Centre (CSN), has integrated the RGN with the National Seismological Network (RSN), setting up a single geodesic network, processed and analyzed by the IGM to serve in supporting the geo-referencing of geoscience-related tasks being performed in this country. This geodesic infrastructure has been affected by a series of earthquakes derived from the dynamics of plate tectonics in Chile, among them: 2010, south-central Chile, 8.8 Mw; 2014 far northern Chile, 8.2 Mw; 2015, central-northern Chile, 8.4 Mw; and 2017, Chiloe Island (southern Chile), 7.6 Mw.

The IGM, together with Chilean and international organizations, scientifically studies and analyzes the deformation of the tectonic plates over its various phases, using data from the network of permanent GNSS stations to calculate the Co-seismic and Post-seismic displacements, determining changes to the coordinates during earthquakes and the drift of the plates over the periods following the seismic movement. These differences are portrayed by means of vectors to scale, that indicate magnitude and direction of the deformation. Thus shifts are detected that range from centimeters to meters, affecting the accuracy of the SIRGAS-Chile Reference Framework, so it has been necessary to calculate coordinates referenced to the 2002.0, 2010.0, 2013.0 and 2017.0 epochs, which makes it possible to guarantee that the coordinates given to users are as accurate as possible.