it gets to the point where thrusting makes a difference. But there are other complexities as well. Hellenic Trough morphology A number of mapping techniques have been applied to research the arc zone, such as seafloor mapping, reflection seismology, and application of the Global Positioning System, which can detect changes of position in millimeters; i.e., geologic movement, good for measuring geologic velocities. The work done so far indicates that the appearance of symmetry is an illusion based on the shape of the forearc; that is, on the raised arc of the margin of the overriding plate. Bathymetric representations of the Hellenic Trench to the south of the arc depict a different shape. As far as the major parameters are concerned: fault type, dip, depth, velocity, seismicity, etc., the subduction zone in the trench is asymmetric, which some consider a unique distinction. The zone begins near the Gulf of Corinth and trends ESE in an arc approximating a straight line. It terminates to the south of Crete in an angular vertex. This leg of the HT contains mainly dip-slip faults (a hanging wall slips up or down over the dip of a floor wall). North of its end on the west another subduction zone is created by the Adriatic Plate diving under the Balkans, which are in the Eurasian Plate proper, and not the Aegean Plate. The subduction line between the two is not continuous; there is a gap of about . Between the south end of the Adriatic Plate subduction and the north end of the Aegean Plate subduction is the Kephallenia Fault Zone (KFZ), or Kephallenia Transform Fault (KTF), or Cephalonia-Lefkada Transform Fault Zone (CTF). The Aegean Plate slips along the side of the Adriatic Plate in a SSW direction. A second leg trends N60E, which is ENE, to the island of Rhodes, where it ceases. There is not a singular vertex. Prior to reaching its end point the ESE leg has two more vertices, so that the ENE leg is distributed into three ENE lines, the Ptolemy Trench, the Pliny Trench outside of and parallel to it, and the outer Strabo Trench, parallel to the other two. The overall appearance resembles an arc inscribed in a vertex angle, except for the asymmetry. The three trenches fall short of Rhodes, the Strabo Trench going the farthest east. Between it and the Cyprus Trench are the Anaximander Mountains, a submarine