Bathymetry and shallow structure of the Pliny and Strabo Trenches, south of the Hellenic Arc
The Hellenic Arc is bounded on its southern side by several deeps, which are considered to be the result of subduction of the African plate below the Aegean plate. The topography of these deeps is more complicated than that observed over the trenches of the western Pacific. Bathymetric and Continous seismic profiling studies show that there are two trenches, the Pliny and Strabo Trenches. The Pliny Trench is the deeper and more dominant bathymetric feature, and its morphology and structure are similar to those observed in most other trenches in the world. The Strabo Trench is little more than a cleft in the sea floor. Normal faulting, indicating tension, has affected the sediments seaward of these trenches. The floor of the Pliny Trench has been downfaulted in several places. Below the inner wall of both trenches, the sediments appear to be disturbed, since few continuous and coherent reflectors occur in the seismic profiles. Fault-plane solutions support the conclusion that this disturbance is a result of thrusting taking place below the inner wall of the Pliny Trench south of Crete and below the inner wall of the Strabo Trench south of Karpathos. Quaternary turbidite sediments encountered in the Hellenic Trench are also present in the Pliny Trench, but a large part of the trench floor and the underlying sediments are disturbed. Disturbance of the underlying sediments is thought to be a result of subduction occurring at a faster rate than sedimentation.