In addition, the magma underlying the volcano came into contact with the shallow marine embayment, resulting in a violent steam eruption.The eruption also generated a 35 to 150 m (115 to 492 ft) high tsunami that devastated the north coast of Crete, 110 km (68 mi) away.Since no human remains have been found at the Akrotiri site, this preliminary volcanic activity probably caused the island's population to flee.
The Thera volcanic events and subsequent ashfall probably sterilized the island, as occurred on Krakatoa.
Only the Mount Tambora volcanic eruption of 1815, Lake Taupo's Hatepe eruption around 180 CE, and perhaps the Baekdu Mountain eruption around 970 CE released more material into the atmosphere during historic times.
Studies have identified four major eruption phases, and one minor precursory tephra fall.
The thinness of the first ash layer, along with the lack of noticeable erosion of that layer by winter rains before the next layer was deposited, indicate that the volcano gave the local population a few months' warning.
Research by a team of international scientists in 2006 revealed that the Santorini event was much larger than the original estimate of 39 km If so, the eruption's Volcanic Explosivity Index was 7.
The volcano ejected up to four times as much as the well-recorded eruption by Krakatoa in 1883.On Santorini, there is a 60 m (200 ft) thick layer of white tephra that overlies the soil clearly delineating the ground level before the eruption.This layer has three distinct bands that indicate the different phases of the eruption.The tsunami affected coastal towns such as Amnisos, where building walls were knocked out of alignment.On the island of Anafi, 27 km (17 mi) to the east, ash layers 3 m (10 ft) deep have been found, as well as pumice layers on slopes 250 m (820 ft) above sea level.The third phase was also characterized by the initiation of caldera collapse.