Download Preliminar results of the Columbo Seamount Ocean

Preliminary results of the Columbo Seamount
Ocean-Bottom-Seismometer and -Tiltmeter experiment
The Columbo submarine volcano is part of the Santorini volcanic complex,
located in the center of the Hellenic volcanic arc, Aegean Sea,
approximately 8km north-east of Santorini (Thira island).
The Columbo has attracted attention due to high seismicity rate and
possible crustal deformation which both might be related to fluid migration
within the volcano and were up to now only observed from Santorini and
the surrounding islands. Within the Columbo experiment, 4 ocean bottom
seismometers (OBS) and 4 newly developed tiltmeters (OBT) have been
deployed for ten months on top and in the vicinity of the seamount (parallel
to the EGELADOS experiment). The aim of the local experiment was to
close the azimuthal gap between the islands and to get precise depth
locations of the events by mounting OBSs directly in the epicentral region
on top of the seamount.
Up to now, a STA/LTA trigger was run over the continuous OBS data and
delivered over 14.000 triggers for local and regional events. At least three
episodes of very high seismicity, partly over a hundred events per hour,
have already been detected. In a first step, we want to apply a threecomponent cross-correlation method on the data, which was delivered and
successfully tested for volcanically triggered earthquake swarms in Iceland
in 2004, in order to increase precision of single event relocations within
seismic clusters and to find possible spatial migrations of these clusters. In
a second step, we will try to compare the tiltmeter data with the behavior
(cluster migration, focal mechanisms etc.) of the earthquake swarms to
find possible relations between crustal deformation and seismicity.