Strong (M ≥ 7.0) Earthquake-Prone Areas in Hellenides, Greece

Abstract

Geological and geomorphological criteria for the areas prone to the earthquakes with magnitudes M ≥ 7.0 are determined for the territory of the Hellenides located in the southern part of the Balkan Peninsula. Intersections of morphostructural lineaments identified by the morphostructural zoning method are considered as seismogenic structures. Geological and geomorphological parameters were determined in a unified manner for all lineament intersections. It is established that earthquake epicenters with М ≥ 7.0 are confined to the intersections of lineaments. The intersections associated with the observed earthquakes with М ≥ 7.0 are used for training the recognition algorithm Cora-3. Based on the geological and geomorphic parameters, the recognition algorithm revealed the characteristic traits according to which all the lineament intersections were classified into the highly seismic (H) (historically called as dangerous, D) and low seismic (L) (historically called non-dangerous (N)) relative to the threshold magnitude М0 = 7.0. As a result, all these intersections were recognized as dangerous, just as another 24 intersections at which the events with magnitude M ≥ 7.0 have not been previously observed. In particular, these intersections are recognized on the Evia Island where the western branch of the North Anatolian fault approaches the coast of Central Greece. Another group of D-intersections is located in the central part of the Gulf of Corinth, the tectonically most active area of the region where, however, the earthquakes with M ≥ 7.0 have not been detected so far. The characteristic traits of D- and N-intersections (seismicity criteria) are formed by the morphometric parameters. The intervals of values of these parameters that are characteristic of D-intersections hint to the processes of subsidence and extension predominant in the areas of these intersections.