The earthquake was felt over a wide area from Alexandria in the southwest to Antioch in the north previously damaged by the earthquake of 526. The area of felt intensity of VIII or more extends from Tripoli in the north to Tyre in the south. Estimates for the magnitude vary from 7.2 on the surface wave magnitude scale to a possible 7.5 on the moment magnitude scale. The rupture length is estimated to be greater than and possibly as long as . The origin of the tsunami was thought to have been due to an underwater landslide triggered by an earthquake on the Dead Sea Transform itself. More recent analysis suggested that an offshore continuation of the Roum Fault mapped onshore was responsible. However, seabed surveys have discounted this possibility and the discovery of geologically recent fault scarps at seabed indicate that movement on the newly identified Mount Lebanon Thrust was the cause of the earthquake and the resulting tsunami. Quaternary uplift recorded by a series of marine-cut terraces between Tripoli and Beirut are consistent with continuing upward movement of the hanging wall of the proposed thrust. At a smaller scale, an uplifted vermetid bench, which indicates vertical movement of about 80 cm, is dated to the sixth century A.D. Continued uplift above this thrust since the late Miocene may explain the formation of the Mount Lebanon range.