25 Nearshore and Estuarine Research: Dynamics and Future Resiliency in the Coastal Zone II

This session focuses on drivers of change in coastal environments as well as planning for future resiliency in tidal marshes, mudflats, estuaries, and barrier systems, including human activity impacts, sea level rise, & changing sediment supply.

Monday, 23 March 2026
1:30 PM - 5:30 PM
CCC, Room 22/23

Santorini Tsunami Risks to the Aegian and Mediterranean Urban Population Centers- A Geological Perspecttive

Paper number: 25-10
Program: Technical Sessions
Time: 4:30 PM – 4:50 PM

Authors

Abstract

Santorini is located in the Pliocene Hellenic Volcanic Arc, a chain of volcanoes formed by the subduction of the African Plate beneath the Aegean microplate. Recently 28,000 Santorini earthquakes, with 4 > 5 on the Richter scale, recorded by the Institute of Geodynamics, National Observatory of Athens, caused school closings, restrictions on gatherings and the evacuation of  residents. The purpose of this presentation is to evaluate the potential current risks to the urban populations (8.5 million) of Crete and Eastern Mediterranean in addition to Santorini.  (32,500 including tourists).

The primary Santorini catastrophic eruptions of Thera (VEI 7) that occurred using radiocarbon dates of the volcanic destruction layer (VDL) range from 1603 BCE to 1502 BCE, while tree rings dating 1602 BCE and 1524 BCE.

The Thera eruption deposited four distinct layers; (Karatson et. al., 2020), Unit A) 6m pumice ash, Unit B) 10m pyroclastic surges and lava, Unit C) 55 m low- temperature pyroclastic flow and pumice deposits, and Unit D) tens of meters of phreatomagmatic high-temperature lithic-rich base surge, lava flows, lahar floods, and ash-fall deposits.

Evidence of tsunami deposits with marine layers embedded in nonmarine depositional sequences is scarce (20). In northern Crete, cores represent a 6 cm medium sand layer, a 20 cm thick multimodal composition mixture of medium sand and fine silt containing mollusks and echinoderm fragments, with intact and broken marine microfossils. Numerical modelling suggests two tsunamis; one from pyroclastic flow and the second from caldera collapse; 28m and 24m respectively affecting Crete (Free et., al. 2011).

In offshore Caesarea Israel, the tsunami layer (40 cm) included erosional lower contacts, fining upward particle-size distribution, individual groups of mollusks, rip-up clasts, rafted pumice and distinctive microfossil assemblages (foraminifera).   Numerical models confine the major tsunami amplitudes near of the offshore deepwater Nile Delta where tsunamis do no occur.  Abril and Perianez  (2015) proposed submarine landslides or tectonically activated fault systems derived propagation based on 2-D depth-average nonlinear barotropic shallow water equations suggest maximum waves of 10-15 m on the eastern  Sinai, Gaza, and Southern Israel Coasts

An eruption near Santorini would threaten with the highest risk local tsunamis in the Aegean Sea; A 10-20minute travel reaction times, lower risk to eastern  Sinai, Gaza.   Israeli Coasts, with  90 minute reaction time.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411088

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