The objective of the MT part of the observatory is to monitor and analyse electromagnetic data to decipher possible changes in the subsurface electrical resistivity distribution. After elimination of a geomagnetic source field effect which strongly affects the measurements, we examine remaining temporal electromagnetic field variations.
The great Sumatra fault (SF) is one of the most prominent examples for large strike-slip fault systems developing along subduction zones. A passive seismological experiment is carried out in northern Sumatra, close to the city of Banda Aceh. Our temporary seismological network is covering an interesting segment of the SF, which is also characterized by increased surrounding volcanic activity.
The San Andreas fault (SAF) is one of the most studied strike-slip faults in the world - yet its subsurface geometry is still uncertain in most locations. The Salton Seismic Imaging Project (SSIP) was undertaken to image the structure surrounding the SAF and also its subsurface geometry. Such data are useful as input for modeling scenarios of strong ground shaking in the surrounding high-population areas. As part of long-term cooperations between GFZ and partners in the U.S. we apply pre-stack depth migration methods to obtain images of steeply dipping structures around the SAF in southern California.
In a series of geophysical experiment we study deep structures and geodynamic processes in the Tien Shan and Pamir collision zones, central Asia. The magnetotelluric (MT) component addresses topics such as middle crustal flow, stress relaxation due to partial melting and fluid release in continental subduction processes.