Τίτλος:
Magma accumulation beneath Santorini volcano, Greece, from P-wave tomography
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Despite multidisciplinary evidence for crustal magma accumulation below Santorini volcano, Greece, the structure and melt content of the shallow magmatic system remain poorly constrained. We use three-dimensional (3-D) velocity models from tomographic inversions of active-source seismic P-wave travel times to identify a pronounced low-velocity anomaly (-21%) from 2.8 km to 5 km depth localized below the northern caldera basin. This anomaly is consistent with depth estimates of pre-eruptive storage and a recent inflation episode, supporting the interpretation of a shallow magma body that causes seismic attenuation and ray bending. A suite of synthetic tests shows that the geometry is well recovered while a range of melt contents (4%-13% to fully molten) are allowable. A thin mush region (2%-7% to 3%-10% melt) extends from the main magma body toward the northeast, observed as low velocities confined by tectono-magmatic lineaments. This anomaly terminates northwest of Kolumbo; little to no melt underlies the seamount from 3 to 5 km depth. These structural constraints suggest that crustal extension and edifice loads control the geometry of magma accumulation and emphasize that the shallow crust remains conducive to melt storage shortly after a caldera-forming eruption. © 2019 Geological Society of America. For permission to copy.
Συγγραφείς:
McVey, B.G.
Hooft, E.E.E.
Heath, B.A.
Toomey, D.R.
Paulatto, M.
Morgan, J.V.
Nomikou, P.
Papazachos, C.B.
Περιοδικό:
Geologie Mediterraneenne
Εκδότης:
Geological Society of America
Λέξεις-κλειδιά:
Percolation (fluids); Seismology; Tomography; Volcanoes, Caldera-forming eruption; Crustal extension; Low-velocity anomaly; Magmatic systems; Seismic attenuation; Structural constraints; Threedimensional (3-d); Tomographic inversion, Seismic waves, caldera; magma chamber; P-wave; seismic attenuation; seismic tomography; seismic velocity; travel time, Cyclades; Greece; Greece; Santorin; Santorini [Southern Aegean]; Southern Aegean
