DGPS AND MAGNETOTELLURIC CONSTRAINTS ON THE CONTEMPORARY TECTONICS OF THE SANTORINI VOLCANIC COMPLEX, GREECE

Résumé 0

The study of vertical and horizontal crustal movements at the Santorini Volcanic Complex (SVC), as deduced by Differential GPS measurements revealed that an intricate pattern of five distinct domains with different horizontal kinematics: The West SVC (Akrotiri peninsula and Therassia) with very significant NNW-ward motion, North Thera with rather significant NW-ward motion, East Thera (Monolithos), with significant SE-ward motion, South Thera with significant NW-ward motion and, finally, central Thera with small westward motion. An apparently dextral, NNW-SSE oblique-to-strike-slip fault emerges as a prominent tectonic structure, separating the West SVC from the rest of the complex; this is the “Santorini Fault Zone”. Additional insight is afforded by the results of MT and GDS surveys: a significant NNW-SSE conductive zone was detected, which is collocated with the purported NNW-SSE fault zone indicated by DGPS analysis and may be explained as an epiphenomenal conductivity anomaly. The observed deformation pattern enables the drafting of a qualitative model of contemporary tectonics, which is also presented and discussed. The model is plausible but certainly incomplete and pending verification with numerical modelling and additional observations