The most reliable of the globally available relative data have been used to derive empirical for mulas which relate the subsurface fault length,

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During a 7‐week microearthquake experiment conducted in Epirus, Akarnania, and the Ionian islands of western Greece, we located approximately 600 earthquakes with magnitudes between 2 and 4.2. No event was deeper than 40 km. The seismicity cannot be clearly associated with any single fault except the Lixourion right‐lateral fault located west of the Ionian islands. Focal mechanisms of about 100 earthquakes show, for a narrow band of earthquakes located along the coast, ENE–WSW shortening consistent with the surface tectonics. Farther east, focal mechanisms show NNW–SSE extension beneath the foothills of the Pindus mountains, which is unrelated to surface faulting but is consistent with the presently subsiding basins. This strain pattern is seen far north and south of the Lixourion fault and is similar to the one observed in the Peloponnese. It suggests that a large‐scale mechanism is responsible for the recent geodynamics of both the northwestern and southwestern Aegean

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The preshock (critical) regions of 20 mainshocks with magnitudes between 6.4 and 8.3, which occurred recently (since 1980) in a variety of seismotectonic regimes (Greece, Anatolia, Himalayas, Japan, California), were identified and investigated. All these strong earthquakes were preceded by accelerating time-to-mainshock seismic crustal deformation (Benioff strain). The time variation of the cumulative Benioff strain follows a power law with a power value (m ‫ס‬ 0.3) in very good agreement with theoretical considerations. We observed that the dimension of the critical region increased with increasing mainshock magnitude and with decreasing long-term seismicity rate of the region. An increase of the duration of this critical (preshock) phenomenon with decreasing long-term seismicity rate was also observed. This spatial and temporal scaling expresses characteristics of the critical earthquake model, which are of importance for earthquake prediction research. We also showed that the critical region of an oncoming mainshock coincides with the preparing region of this shock, where other precursory phenomena can be observed.

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The Mw = 6.4 July 26, 2001 Skyros (North Aegean, Greece) earthquake struck the submarine western end of Northern Aegean Sea causing damage in the nearby Skyros Island. It occurred on a left‐lateral NW‐SE trending strike slip fault, oriented transverse to the dominant dextral strike‐slip faults that are present in the area, appearing to mark the boundary between them and the E‐W trending normal faults of the Greek mainland. Foreshock activity started 5 days before the mainshock, and intense aftershock activity followed on the main rupture plane and off fault. The seismogenic structure consists of three clusters with different orientation, independent from the known normal and dextral strike‐slip faults. Theoretical static stress changes from the main shock suggests off‐fault aftershock triggering, providing a tool for assessing the seismic hazard ensuing from strong aftershocks far from the main rupture.