SEISMICITY AND STRAIN IN THE GULF OF CORINTH (GREECE) SINCE 1694

Abstract

We use the record of earthquakes in central Greece since 1694 to estimate the seismically-released strain in that region over the last 300 years. The highest strain rate is seen in the Gulf of Corinth, an extensional graben which is the most prominent active geological structure. Over the 300-year period, the earthquakes account for an average extension rate of about 11 ram/yr between the Peloponnese and the island of Evvia, of which about 10 mm/yr occurs in the Gulf of Corinth. The earthquakes occurring in shorter time periods, perhaps as little as 100 years, account for extensional velocities similar to the 300 year average, though the 20th Century has been relatively quiescent. We are not confident that the historical record can be used to assess seismic strain release in areas smaller than the Gulf of Corinth as a whole. The similarity between the average rate of seismic strain release over 300 years and the short-term strain rates measured geodetically suggests that the bulk of the tectonic strain in this region is released by seismic slip on faults, and that aseismic creep is relatively unimportant. An apparent deficit in seismic strain release over a short period (as is observed for the 20th Century) is thus likely to be remedied by future earthquakes.

Keywords:

• seismicity
• strain
• Greece