ROV exploration of Santorini Caldera, Greece. Nomikou, P.

ROV EXPLORATION OF SANTORINI CALDERA, GREECE

Nomikou P.¹*, Croff Bell K.², Bejelou K.¹, Parks M.³, Antoniou V.¹

1 National and Kapodistrian University of Athens, 15784 Zographou, Athens, Greece 2 Graduate School of Oceanography, University of Rhode Island, Narragansett Bay Campus, USA

3 University of Oxford, UK

10ο Πανελλήνιο υμπόςιο Ωκεανογραφίασ & Αλιείασ7-11 Μαϊου 2012, Αθήνα

(Nomikou et al., 2012-Tectonophysics-in press)

These three main volcanic centers

and all the smaller volcanic cones

northeast of Kolumbo, are

aligned along the NE-SW trending

Santorini-Kolumbovolcano-tectonic

line

(Nomikou et al., 2012

GLOPLACH)

Καταδφσεις με το Βαθυσκάφος «ΘΕΤΙΣ» του ΕΛΚΕΘΕ (2005, 2007)

SKAI

www.explorenautilus.gr (2011)

Remotely Operated Vehicles

Nomikou et al., (2012)

389 m

325 m

297 m

Sigurdsson et al., 2006

Hydrothermal vents occur in both the

North and South Basin of the caldera.

They form a vent field in the NE part

of the North Basin that is 200 by 300m

in extent. The vents form hundreds of

1 to 4m diameter mounds of

yellowish bacterial mat that are up to

1m high. Temperatures in the mound

are around 15 to 17 C or about 5 C

above ambient temperature. The North

Basin hydrothermal vent field is

located in line with the normal fault

system of the Kolumbo rift, and also

near the margin of a shallow intrusion

that occurs within the sediments of the

North Basin. Similar vent mounds

occur in the South Basin, where most

of the low temperature vents are seeps

along a ridge separating the West and

South Basins and on the submarine

flanks of the Kameni volcanic islands.

Tectonic graben in line

with Kolumbo line

(NE-SW direction)

500m depth

The caldera rim lies at about 150 m depth forming a submarine circular cliff of 350 m.The crater walls display a scalloped morphology that is visible by undulating contour lines.

The topographic difference is apparently created by the collapse of a relevant volcanic cone

Swath Bathymetric Map of Kolumbo Volcano

Nomikou et al., (2012-in review)

“Poet’s Candle”

Carey et al., 2011, Oceanography

Οι υδροθερμικϋσ

καμινϊδεσ παρουςιϊζουν

υψηλό πορώδεσ, με

ϋναν κεντρικό αγωγό που

δομεύται από ςουλφύδια και θειώκϊ ϊλατα και βοηθϊ τη

ροό των ρευςτών προσ

τα ϋξω.

Parks et al., 2012, Nature (in review)

Our soil gas surveys detected an apparent increase in CO2

emissions between July 2011 and September 2011. CO2

effluxes now exceed 12 kg m-2 day-1, with a total flux of 39 tonnes of CO2 per day (Parks et al, 2012)

The source has an effective volume of 1−2×107

m3 for the full year of 2011, and is centredslightly to the north of Nea Kameni at a depth of 4-7 kilometres.

Nomikou et al., 2011, Tectonophysics (in press)

Nomikou et al., 2012

1866-1870

1939-1941

726

1570-15731707-1711

1925-1928

46

Shimmery water 25 C

Ω/Κ ΑΙΓΑΙΟΙΑΝΟΥΑΡΙΟ 2012

Nomikou et al., (2012)

under preparation