Imaging crustal discontinuities and the downgoing slab beneath western Crete

The migration of teleseismic receiver functions yields high-resolution imag es of the crustal structure of western Crete. Data were collected during tw o field campaigns in 1996 and 1997 by networks of six and 47 short-period t hree-component seismic stations, respectively. A total of 1288 seismograms from 97 teleseismic events were restituted to true ground displacement with in a period range from 0.5 to 7 s. The application of a noise-adaptive deco nvolution filter and a new polarization analysis technique helped to overco me problems with local coda and noise conditions. The computation and migra tion of receiver functions results in images of local crustal structures wi th unprecedented spatial resolution for this region. The crust under Crete consists of a continental top layer of 15-20 km thickness above a 20-30 km thick subducted fossil accretionary wedge with a characteristic en echelon fault sequence. The downgoing oceanic Moho lies at a depth of 40-60 km and shows a topography or undulation with an amplitude of several kilometres. A s a consequence of slab depth and distribution of local seismicity, the Med iterranean Ridge is interpreted as the recent accretionary wedge.