Volatiles and Fluids in Subduction Zones

Marine MT

Marine MT (tutorial) has been successfully employed in various settings and different depth scales to image partial melt zones in the crust and mantle along mid ocean ridges (e.g. Jegen and Edwards, GRL, 1998; Evans et al., 2004) and potentially oilbearing reservoirs covered by basalt and salt layers (Jegen and Hobbs, 2004; Hoversten et al., 2000) . Pilote studies are under way to use marine MT on subduction zones.

Modelling studies have shown that in order to obtain a reliable resistivity profile across a subduction zone, on-shore offshore profiles are necessary, even if the target is purely on the terrestiral or marine side (Evans et al., 2002) .

In the framework of the SFB we are currently building 10 highly sensitive marine MT stations, which will be deployed across the Nicaraguan subduction zone simultaneous to a land MT survey.

The Geomar MT station.