Moho topography under central Greece and its compensation by Pn time-terms for the accurate location of hypocenters: The example of the Gulf of Corinth 1995 Aigion earthquake

摘要

In this paper we expand over the whole of central Greece, the Moho map centered on the Gulf of Corinth from tomographic inversion of PmP traveltime profile data recorded by several tens of temporary stations. Our approach is based on Pit, Moho refracted waves, from a large regional earthquake recorded by both temporary stations and the permanent Hellenic network. The Moho map shows the large Moho depth under the Hellenides belt. It also highlights the shallower Moho domain towards the Aegean Sea south and east of the Corinth Gulf. The domain of shallow Moho is limited along a NE-SW prolongation ahead of the North Anatolian Fault, from the North Aegean Trough to the western tip of the Gulf of Corinth towards the Gulf of Patras. The Pit time-terms provide corrections for the permanent stations that can be used together with the 1 D velocity-depth model for a first-order compensation of lateral heterogeneity and contribute to the accurate and fast location of earthquake hypocenters. As a test we relocated the 1995 Aigion earthquake in this way, using only the sparse data of the permanent stations. Hypocentral coordinates then shift close to those derived by a dedicated dense array deployed after the earthquake, implying improvement of the routine location. (c) 2007 Elsevier B.V. All rights reserved.