A Tour of the islands of Santorini by Jack Simmons, Monash Uni, Aus


Santorini is a continental arc caldera, characterised by the islands of Thera, Therasia, Aspronisi, Palea Kameni and Nea Kameni. These islands record 650 kyr years of volcanic activity including multiple lava shields, lava domes, stratovolcanoes, 12 major explosive eruptions (Thera Pyroclastics) and two 180 kyr explosive cycles (Druitt et al., 1989; Druitt et al., 1999). These cycles were terminated by the rhyodacitic Lower Pumice 2 and Minoan eruptions. The present day caldera resulted as a consequence of the recent 3.6 ka Minoan eruption, which was responsible for the demise of the Minoan civilisation on Santorini. The Minoan eruption commenced with the development of a 36 km high eruption column which buried a Minoan settlement near the town of Akrotiri, on Thera (Sigurdsson et al., 1990; Sparks and Wilson, 1990). Vent widening and the development of new vents resulted in the development of pumice-rich pyroclastic flows. The bulk of these pyroclastic flows traveled across and were deposited in the Aegean Sea (Druitt et al., 1999; Druitt, 2014). A tsunami associated with this eruption phase, traveled as far south as Crete (almost 200 km south of Santorini), and probably had a significant impact on the local inhabitants (Antonopoulos, 1992). The intracaldera lava domes of Palea Kameni and Nea Kameni record that latest phase of volcanism at Santorini (Druitt et al., 1999; Pyle and Elliott, 2006). The most recent eruption occurred in 1950. Monitoring of the Santorini volcano by the Institute for the Study and Monitoring of the Santorini Volcano has been ongoing since 1995. Eruption dates detailed in the above figure are from Druitt et al. (1999), Keller et al. (2000), Friedrich et al. (2006), Lee et al. (2013) and Fabbro et al. (2013).


Pic 1. Panorama of the Santorini volcano from Mt Profitis Illias, Thera.


Pic 2, 3, 4. Early Volcanic Centers of the Akrotiri Peninsula and Peristeria volcano. A: Peristeria volcano, Northern Thera (ca. 528-308 ka), with sub-vertical dykes. B: Cape Mavrorachidi scoria cone, Red Beach, Thera (ca. 522-451 ka). C: Cape Balos Maar-Scoria cone complex, Akrotiri Peninsula, Thera (ca. 344ka).


Pic 5. Thera Pyroclastics at Athinios, Thera. The upper beige unit are the deposits of the 3.6 ka Minoan eruption.


Pic 6. Deposits of the 184 ka Lower Pumice 1 eruption including a large ballistic impact bomb which intrudes into the underlying deposits, Cape Balos West, Thera.


Pic 7. Pyroclastic fall deposits of the 172 ka Lower Pumice 2 eruption overlying exposed basement assemblages at Athinios, Thera.


Pic 8. Pyroclastic fall deposits of the 3.6 ka Minoan eruption overlying settlements of the Minoan civilization, Akrotiri excavation site, Thera.


Pic 9. Volcanic vents of Nea Kameni in the present caldera. This island formed via the eruption and emplacement of multiple lava flows.

References Cited

Antonopoulos, J., 1992. The great Minoan eruption of Thera volcano and the ensuing tsunami in the Greek Archipelago. Natural Hazards, 5(2): 153-168.

Druitt, T.H., 2014. New insights into the initiation and venting of the Bronze-Age eruption of Santorini (Greece), from component analysis. Bulletin of Volcanology, 76(2): 1-21.

Druitt, T.H., Edwards, L., Mellors, R.M., Pyle, D.M., Sparks, R.S.J., Lanphere, M., Davies, M. and Barreirio, B., 1999. Santorini Volcano. The Geological Society, London.

Druitt, T.H., Mellors, R.A., Pyle, D.M. and Sparks, R.S.J., 1989. Explosive volcanism on Santorini, Greece. Geological Magazine, 126(2): 95-126.

Fabbro, G.N., Druitt, T.H. and Scaillet, S., 2013. Evolution of the crustal magma plumbing system during the build-up to the 22-ka caldera-forming eruption of Santorini (Greece). Bulletin of Volcanology, 75(12): 1-22.

Friedrich, W.L., Kromer, B., Friedrich, M., Heinemeier, J., Pfeiffer, T. and Talamo, S., 2006. Santorini eruption radiocarbon dated to 1627-1600 B.C. Science, 312(5773): 548.

Keller, J., Kraml, M. and Schwarz, M., 2000. Dating major volcanic paroxysms within the deep-sea record: the example of the Thera Formation, Santorini, Greece, IAVCEI General Assembly, Bali, Indonesia, pp. 16.

Lee, S., Ramsey, C.B. and Hardiman, M., 2013. Modeling the age of the Cape Riva (Y-2) tephra. Radiocarbon, 55(2-3): 741-747.

Pyle, D.M. and Elliott, J.R., 2006. Quantitative morphology, recent evolution, and future activity of the Kameni Islands volcano, Santorini, Greece. Geosphere, 2(5): 253-268.

Sigurdsson, H., Carey, S. and Devine, J.D., 1990. Assessment of Mass, Dynamics and Environmental Effects of the Minoan Eruption of Santorini Volcano. In: D.A. Hardy, J. Keller, V.P. Galanopoulos, N.C. Flemming and T.H. Druitt (Editors), Thera and the Aegean World III. The Thera Foundation, London, pp. 100-112.

Sparks, R.S.J. and Wilson, C.J.N., 1990. The Minoan Deposits: A review of their Characteristics and Interpretation. In: D.A. Hardy, J. Keller, V.P. Galanopoulos, N.C. Flemming and T.H. Druitt (Editors), Thera and the Aegean World III The Thera Foundation, London, pp. 89-9