QUANTITATIVE ANALYSIS OF THE ARKITSA FAULT ZONE (NORTH EVIA GULF, CENTRAL GREECE): IMPLICATIONS FOR KINEMATICS, PALEOSEISMIC ACTIVITY AND FLUID FLOW
Quantitative analysis of LiDAR data along three well-exposed fault panels allowed the spatial variation in various geometrical properties across the fault surface to be clearly shown. Fault-slip analysis from each panel shows that the local stress ﬁeld is consistent with the regional velocity ﬁeld derived from recent GPS data. Furthermore, we studied the fault-gouge mineralogy in order to understand the faults’ enigmatic aseismic behavior and if the conditions that characterize the fluid flow can be identified. Clay-gouge samples were collected within the fault core zone, as well as in the broader fault damage area and analyzed by XRD, SEM and Electron microprobe analyses. The absence of corrensite, a clay mineral usually formed in hydrothermal conditions, in the samples from the broader fault damage zone indicates that the circulation of hydrothermal fluids is mostly confined within and around the fault core zone. The assemblages within the fault gouge zone and especially the presence of corrensite, combined with the absence of laumontite, indicate hydrothermal alteration at neutral to alkaline conditions and at a temperature range of about 100-150 o C.