The GFZ German Research Centre for Geosciences has been monitoring this gap with the Integrated Plate Boundary Observatory (IPOC) in Chile since 2006, and now the duties will be taken up the Universidad de Chile and the Universidad Catolica del Norte.
"This last non-ruptured segment of the Earth's crust off the Chilean west coast is highly interesting for geosciences in the whole world," said Reinhard Huettl, a scientists working on the project. It is, however, not simply a question of earthquakes. The aim is to continuously measure all processes in connection with the dynamics of this plate boundary.
Approximately one-third of the world-wide seismic energy has discharged during the last century in earthquakes with magnitudes of over M = 8 along the South American-Pacific plate boundary. The repeat-time between two large earthquakes is shorter here than almost anywhere else on our planet.
The IPOC project investigates the area around Iquique on the South American Nazca Plate Boundary. Within the next years a strong to devastating earthquake will occur in this area, the scientists predict. Within the framework of investigations, deformation, seismicity, and magnetotelluric fields in the subduction zone will be monitored, i.e. in the periods before, between and possibly also during a quake.
"Currently the monitoring network consists of 20 seismological stations, equipped with broadband seismometers and acceleration sensors," said Professor Onno Oncken, Director of the Department Geodynamics and Geomaterials at the GFZ. In order to do justice to the requirements for dissolution and efficiency of the sensors and data capture, special care was given to choosing the exact location. Thus, at each station a lug of approx. 5 m deep was blown into the rock bed, in order to ensure stable site conditions for the monitoring instruments.
All seismic installations are equipped with the new-generation GPS-instruments. Seven measuring points were furthermore equipped beyond that with magnetotelluric measuring instruments and serve for the measurement of electric current in the Earth's crust.
"Due to the numerous expeditions and measuring campaigns over the years in this subduction zone," says Oncken, "the GFZ now holds the densest data set world-wide for such an area. When we monitor the conditions before, during and after a large quake this serves to help develop a hazard model for this and similar regions."
A strong quake in this region could have consequences for the global economy: the earthquakes thjere develop through the subduction of the Pacific-floor under South America. The same process also leads to the formation of ore deposits in the Earth's crust. Thus, the largest copper deposit of the world is to be found on the western boundary of the Central Andes. A strong quake could interrupt or even endanger the global supply of copper and lithium.