Detection and imaging of fluids in the down-going slab as a controlling factor in the subduction and rupture process and their interaction with deep-reaching fault zones in the forearc is a major objective of a joint offshore/onshore passive electromagnetic experiment. The MT field work requires a dense network of MT sites onshore to account for lateral variations of electrical structures and the N-S trend of bathymetry. The electromagnetic deep sounding experiments are conducted by the MT working group of the FU Berlin (H. Brasse).
The magnetotelluric method is also a part of the combined seismic-magnetotelluric-geodetic monitoring network. In the first phase, which started in November 2004, a network of 3 stations (SMG1-3, see figure below) was installed. The sites are aligned along an EW profile extending from the Atlantic Ocean to the volcanic arc. The overall goal is to detect transient events which are related to the subduction system by means of recording and imaging the local and regional seismicity distribution and the long-term variability of geomagnetic transfer functions. Synchronous recordings of GPS and seismic broadband data (periods up to hours) will allow us to examine a wide spectrum of earthquake styles: between seismic (sudden-onset) rupture and continuous or a-seismic slip.
TIPTEQ is funded by the Federal Ministry of Education and Technology (BMBF). We gratefully acknowledge participation in the field (Pablo Salas) and the logistcal support of the Universidad de Concepcion (Klaus Bataille).
Methods & Equipment