seismic stratigraphy od santorini's caldera: a contribution to the understanding of the minoan...
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10ο Πανελλήνιο Συμπόσιο Ωκεανογραφίας & Αλιείας 7-11 Μαΐου 2012, Αθήνα Μεσόγειος Θάλασσα - Μαύρη Θάλασσα: Ένα ωκεανογραφικό «εργαστήριο»TRANSCRIPT
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 Research2 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 & Αλιείας7-11 Μαϊου 2012, Αθήνα
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
North B
asin
South Basin
West Basin
Cape RivaCaldera
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
Pre-eruption relief
Air fall Tephra
Pyroclastic flows, surges
Lahars and pyroclastic flows
Minoan eruption deposits onshore
Minoan eruption Phase 1:Coarse grain air-fall tephra layer
Thickness: 10-11m max
Morphology of the submarine volcanic flanksYoung, upper slopes: steep, irregular
Old, lower slopes: gently sloping, smooth
Airgun 10ci profile 90-91
NORTH BASIN
Seismic stratigraphy of Santorini Caldera
NORTH BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 39-38
NORTH BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 40-41
NORTH BASIN
Seismic stratigraphy of Santorini Caldera
Deep Tow CHIRP profile 40-41
NORTH BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 43-42
WEST BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 87-88
SOUTH BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 88-89
SOUTH BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 47-48
SOUTH BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 51-50-49-48
SOUTH BASIN
Seismic stratigraphy of Santorini Caldera
Airgun 10ci profile 49-48
Kameni lavas
Floating pumice
PyroclasticsPyroclastics
Pre-Minoan
Pre-Minoan
Air-fall tephra
slide
Interpretation of the seismic stratigraphy of Santorini’s Caldera
Cape Riva CalderaEruption took place outside the Santorini Caldera.Cape Riva pyroclastics flew into the caldera through the northern corridor.
Structural evolution of Santorini’s Caldera
(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 17th cent. BC eruption
(v) the Minoan eruption center was located where the present day Kameni islands are.
RESULTS
EUROFLEETSCaldera 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
1.00E-11
1.00E-10
1.00E-09
1.00E-08
1.00E-07
1.00E-06
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46
mass-to-charge ratio
ion
pea
k in
ten
sity
(T
orr
)
ambient vent
CO
H2S
CO2
CH4
Hydrocarbon?
NOx
Mapping gas concentration in real time with the TETHYS mass spectrometer,
mounted on THETIS submersible
EUROFLEETSCaldera 2012
January 2012ROV Max Rover diveNorth of Nea Kameni380m depth
Small crater on the Caldera’s seafloor
EUROFLEETSCaldera 2012
THANK YOU
santorini.hcmr.gr