Three-dimensional structure and constraints on the nature of the coupled subduction-spreading process in the Aegean area

Abstract

P-wave travel-time residuals from stations of the Athens Observatory network are inverted by a tomographic technique to investigate the velocity structure of the lithosphere in the Aegean region. Both local and teleseismic data are used. The velocity anomalies are best resolved in the mantle lithosphere and indicate a markedly heterogeneous velocity structure. These results, described elsewhere in more detail, are correlated in this paper with other geophysical fields in the area. The velocity heterogeneity observed in the upper mantle is very well correlated with thermal data and other geophysical fields in the Aegean. In particular, the present-day active extension in the Aegean takes place behind the volcanic arc where in the mantle lithosphere velocity anomalies lower than “normal” are observed, consisted with a “stretched” lithosphere in the back-arc. The area associated with the strongest Bouguer and Free-air anomalies occurs in the southern Aegean (Sea of Crete), above a zone of relatively higher velocity anomalies.