Imaging the Geometry of Cimandiri Fault Zone Based on 2D Audio-Magnetotelluric (AMT) Model in Nyalindung, Sukabumi–Indonesia

Abstract

We present an interpretation of newly acquired audio-magnetotelluric data to reveal the subsurface geometry of Cimandiri Fault Zone, one of the major active faults in the western part of Java. The line section is 25 km long in a nearly north–south direction across the axes of CFZ with 24 stations of 750–1200 m spacing intervals. The 2D AMT inversion model shows two conductive zones in the southern part that may be associated to the Miocene rocks of the Southern Mountains, and a conductive zone in the northern part that is likely to be associated with Gunung Walat fold-belt. The subsurface structures of the Southern Mountains are dominated by south-dipping thrusts that may uplift the shallow marine sediments. Shallow seismicity occurred around CFZ indicating the activity of these blind thrusts.