Description
This 3D model encompasses an area of 730x300m, in the NE corner (view to the NE) of the northern caldera wall on Santorini island, Greece; the cliff is 190 m high. Santorini is a volcanic island located in the Aegean Sea, representing the southernmost part of the Hellenic active volcanic arc (Le Pichon and Angelier, 1979). It has experienced at least four caldera collapse events and is still active (Druitt et al., 1999). The last caldera collapse event triggered by the 3.6 ka Minoan eruption formed the currently observed morphology (Heiken and McCoy, 1984; Druitt and Francaviglia, 1992).
The model shows a panorama of the caldera wall, dissected by several, 1-1.5-m-thick vertical dykes (extension fractures). The one on the east (right) strikes about NE-SW, the others strike about N-S. The host rock consists of lava flows, breccia, tuff, scoria and hyaloclastite units, remnants of the ancient Peristeria stratovolcano (530-430ka) and are cut by normal faults (Druitt et al., 1999). The dykes are observed to follow different paths while propagating across the cliff, as a result of the highly heterogeneous and anisotropic host rock. This factor can alter a dyke’s path to the surface: dykes may propagate vertically, get deflected along discontinuities or become arrested. These possible scenarios can play a vital role in the likelihood of a dyke reaching the surface to erupt during an unrest episode (Drymoni et al., 2020).

Credits: UAV-based survey and 3D DOM by Fabio L. Bonali and Luca Fallati; funding is from MIUR project ACPR15T4_00098 (http://argo3d.unimib.it/). The volcanic products were analyzed by Kyriaki (Sandy) Drymoni.

References

  • Caldera formation on Santorini and the physiography of the islands in the late Bronze Age. Bull. Volcanol. 54, 484–493.
  • The Hellenic arc and trench system: A key to the neotectonic evolution of the eastern Mediterranean area. Tectonophysics, 60, 1-42.