Vertical & horizontal ground deformation of Santorini island deduced by DGPS measurements

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Published: Jan 1, 2007
DOI: https://doi.org/10.12681/bgsg.16874
Keywords:
geodetic network subsidence uplift volcanic activity
E. Papageorgiou
Department of Geophysics & Geothermics, School of Geology and Geoenvironment, National and Kapodistrian University of Athens,
E. Lagios
Department of Geophysics & Geothermics, School of Geology and Geoenvironment, National and Kapodistrian University of Athens
S. Vassilopoulou
Department of Geophysics & Geothermics, School of Geology and Geoenvironment, National and Kapodistrian University of Athens
V. Sakkas
Department of Geophysics & Geothermics, School of Geology and Geoenvironment, National and Kapodistrian University of Athens
Abstract

Santorini is considered to be a dormant volcano with fairly high geodynamic unrest. Two major tectonic NE-SW trending fault zones, Kammeni and Columbo Lines, which intersect the main part of the volcanic edifice, have affected the magma flow at relatively shallow depths enabling the appearance of individual volcanic centers on the island. GPS measurements on a network of 18 stations were carried out in 1994 and 2005 in order to estimate the ground deformation, both in vertical and horizontal component. The results show that the highest amplitude of subsidence (45 mm) and uplift (51 mm) is noticed on Nea Kammeni and Cape Columbo, respectively. Considering the horizontal displacements, it appears that these sites were strongly affected by the above major faulting zones. They vary between 4 mm and 37 mm, where the highest amplitudes are observed at the south-western corner of Thera and Therassia Islands. Their directions seem to correlate with the observed subsidence in the caldera (deflation) and a probable inflation around the area of the sub-marine Columbo Volcano.

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  • Geophysics and Seismology
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