New data on the geodynamics of southern Peru from computerized analysis of SPOT and SAR ERS-1 images

Abstract

Several geological structures are extracted from SPOT-Panchromatic and ERS-1 radar images of the Central Andes (Arequipa area, Southern Peru). Our new methodology of numerical image processing is an aid for identification of the structures. This numerical approach helps to locate, characterize and determine the amplitude of the vertical offset of structures. The results show that the NW-SE-trending major faults are principally normal with a small sinistral strike-slip component. The open NE-SW faults are tension gashes. Extension in the studied area trends NE-SW and the major NW-SE-striking faults form an extensional “en échelon” pattern including an active volcanic zone. These new kinematic results lead to a regional geodynamic model which takes into account oblique convergence between Pacific and South America Plates within the Wadati-Benioff zone of the Peru trench.