10ο Πανελλήνιο Συμπόσιο Ωκεανογραφίας & Αλιείας 7-11 Μαΐου 2012, Αθήνα Μεσόγειος Θάλασσα - Μαύρη Θάλασσα: Ένα ωκεανογραφικό «εργαστήριο»

1. SEISMIC STRATIGRAPHY OF SANTORINI’S
CALDERA: A CONTRIBUTION TO THE
UNDERSTANDING OF THE MINOAN ERUPTION
Sakellariou D.1, Rousakis G.1, Sigurdsson H.2, Nomikou P.3,
Katsenis I.4, Croff Bell K.L.2, Carey S.2
1
Inst. Oceanography, Hellenic Centre for Marine Research
2
Graduate School of Oceanography, University of Rhode Island, USA
3
Geology Dptm , National Kapodistrian University of Athens, Ilissia, Greece,
4
Geology Dptm., University of Patras
10ο Πανελλήνιο Συμπόσιο Ωκεανογραφίας & Αλιείας
7-11 Μαϊου 2012, Αθήνα

2. HCMR surveys Cape Riva
in the Caldera Caldera
Multibeam bathymetry 2001,
2006, 2012
Airgun 10ci seismic profiling
2006 & 2012
n
si
Chirp & 3.5kHz subbottom Ba
profiling 2012 rth
No
Side scan sonar imaging
2012
Submersible Thetis dives West Basin
2006
ROV Max Rover dives 2012 South Basin
Seafloor sampling 2006, 2012

3. HCMR surveys
in the Caldera
Multibeam bathymetry 2001,
2006, 2012
Airgun 10ci seismic profiling
2006 & 2012
Chirp & 3.5kHz subbottom
profiling 2012
Side scan sonar imaging
2012
Submersible Thetis dives
2006
ROV Max Rover dives 2012
Seafloor sampling 2006, 2012

4. Minoan eruption deposits
onshore
Lahars and pyroclastic flows
Pyroclastic
flows, surges
Minoan eruption Phase 1:
Coarse grain air-fall tephra layer
Thickness: 10-11m max
Air fall Tephra
Pre-eruption
relief

5. Morphology of the submarine volcanic flanks
Young, upper slopes: steep, irregular
Old, lower slopes: gently sloping, smooth

6. Seismic stratigraphy of Santorini Caldera
NORTH BASIN
Airgun 10ci profile 90-91

7. Seismic stratigraphy of Santorini Caldera
NORTH BASIN
Airgun 10ci profile 39-38

8. Seismic stratigraphy of Santorini Caldera
NORTH BASIN
Airgun 10ci profile 40-41

9. Seismic stratigraphy of Santorini Caldera
NORTH BASIN
Deep Tow CHIRP profile 40-41

10. Seismic stratigraphy of Santorini Caldera
NORTH BASIN
Airgun 10ci profile 43-42

11. Seismic stratigraphy of Santorini Caldera
WEST BASIN
Airgun 10ci profile 87-88

12. Seismic stratigraphy of Santorini Caldera
SOUTH BASIN
Airgun 10ci profile 88-89

13. Seismic stratigraphy of Santorini Caldera
SOUTH BASIN
Airgun 10ci profile 47-48

14. Seismic stratigraphy of Santorini Caldera
SOUTH BASIN
Airgun 10ci profile 51-50-49-48

15. Seismic stratigraphy of Santorini Caldera
SOUTH BASIN
Airgun 10ci profile 49-48

16. Interpretation of the seismic stratigraphy
of Santorini’s Caldera
Kameni lavas
slide
Floating pumice
Pyroclastics
Pyroclastics
Air-fall tephra
Pre-Minoan
Pre-Minoan

17. Cape Riva Caldera
Eruption took place outside the Santorini Caldera.
Cape Riva pyroclastics flew into the caldera through
the northern corridor.

18. Structural evolution of Santorini’s Caldera

19. RESULTS
(i) the thickness of the Minoan deposits on the caldera seafloor
exceeds 100 m locally,
(ii) post Minoan deposits are negligible,
(iii) the lower, gently sloping parts of the slopes around Kameni
islands are of Minoan age,
(iv) all three subbasins of the caldera existed prior to the Minoan
eruption and were filled with pyroclastics during and after the 17 th
cent. BC eruption
(v) the Minoan eruption center was located where the present day
Kameni islands are.

20. EUROFLEETS
Caldera 2012 – July 2012
Girona University - HCMR - IPGP - WHOI
Autonomous Underwater Vehicle “Girona 500”
Payload: multibeam, sidescan sonar, camera, mass spectrometer
Deliverables: microbathymetry, morphology, photomosaic,
geochemical mapping

21. EUROFLEETS
Caldera 2012
Mapping gas concentration in real time
with the TETHYS mass spectrometer,
mounted on THETIS submersible
1.00E-06
CO2
ambient vent
1.00E-07 CH4
CO
ion peak intensity (Torr)
H2S
1.00E-08
Hydrocarbon?
1.00E-09
NOx
1.00E-10
1.00E-11
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46
mass-to-charge ratio

22. EUROFLEETS
Caldera 2012
January 2012
ROV Max Rover dive
North of Nea Kameni
380m depth
Small crater on the Caldera’s seafloor

23. THANK YOU
santorini.hcmr.gr