BKG's Geodetic Observatory in Concepción/Chile detects 3m westward displacement of the whole region
The earthquake of 27 February 2010 has caused tremendous damages in Concepción, the second largest Chilean city, and at the adjoining Pacific coast. Since 2002 the BKG is operating, together with the Univesidad de Concepción, a geodetic observatory with three staff members working there. Due to the largely destroyed communication lines they could not give any notice to Germany before March 02 that they and their families have survived the earthquake and are well.
The geodetic oservatory located at Concepción has been transported to Concepción eight years ago after having been developed and tested in the field for many years at the BKG Geodetic Observatory at Wettzell/Bayerischer Wald. Since its setting-up the observatory at Concepción has contributed with comprehensive high-precision measurements for the implementation of the global spatial reference system and to get further knowledge on changes of the terrestrial body.
Meanwhile a vanguard of the German Governmental disaster relief organization (THW) has transmitted via satellite communication the news that the observatory is largely undestroyed. This is why the THW could instal its basic camp on the territory of the observatory in order to organize and coordinate there all rescue actions for the region of Concepción.
The instruments of the observatory are used to carry out laser observations to satellites and measurements using the satellite positioning systems GPS, GLONASS and the test satellite GIOVE of the European navigation system Galileo. Very Long Baseline Interferometry (VLBI) to radio sources in the deep space are used to derive information about earth rotation. Besides these systems the station is equipped with gravimeters and seismometers informing on the current state of the earth’s crust and on ongoing processes in the interior of the earth.
Unfortunately, there is to date no chance to deliver reliable earthquake forecasts. Scientists are worldwide working to create models for earthquake prediction which is considerably supported by a precise knowledge, collected by geodesists, on the situation of the plate borders where earthquakes have their origin. The great number of earthquakes within the last years reveals that further intensive research and observations of the system Earth have to be carried out in order to be able to make a contribution to infrastructure and services of general interest in tectonically acitve regions.
The BKG computers received signals from the observatory at Concepción until the beginning of the quake on Saturday 7:34 h CET. Some few hours later, from ca 14:00 h on, data transmission began anew to last ca six hours before it finally broke down. The BKG could derive from computations that the region of Concepción has been removed for nearly 3 m in a westward direction, i.e. to the Pacific Ocean. Precise computations to detect changes for the rotation velocity of the Earth and for the rotation axis, which were assumed here and there, have not yet been made. To do so, first of all the recorded VLBI data have to be analyzed.