Determining the Role of Fluids near a Slab Window in Central Anatolia, Turkey by Magnetotellurics Method

Abstract:

Wideband (360 Hz – 2000 sec.) magnetotelluric stations were installed to form two northwest-southeast aligned profiles, crossing Central Anatolian (Ecemis) Fault for imaging the electrical conductivity structure of the crust and upper mantle in Central Anatolia, Turkey as part of an ongoing 5-year U.S. NSF funded multidisciplinary project entitled Continental Dynamics/Central Anatolian Tectonics (CD/CAT). Each magnetotelluric profile is made up of 30 wideband observations with site separations ranging from 1 to 5 km. Preliminary models, developed from wideband magnetotelluric data collected so far were modeled using sophisticated two- and three-dimensional inversion algorithms. Their results suggests that: (i) Central Anatolian Fault near Pozantı presents a sharp electrical conductivity contrast between Nigde-Kirsehir Massif and Anatolide-Tauride Block (ii) While Adana Basin sediments at the southeast appear as highly conductive, features associated with Nigde-Kirsehir Massif appear as clear low conductivity zones (iii) Deeper high conductivity anomalies appear at the vicinity of Central Anatolian Volcanic Province. Two additional profiles are being planned in the area and in addition to wideband observations, long period magnetotelluric (1 sec. – 10.000 sec.) stations are being installed on each profile to image the deep structure. Resulting conductivity models will be compared and/or correlated with results gained from other geophysical disciplines of the project, such as shear wave velocities.