HR: 09:00h
AN: T51C-05    [PDF]
TI: The last stages of subduction in the South-Central Mediterranean reflected in geodetic and seismic strain rates
AU: Jenny, S
EM: sarah@tomo.ig.erdw.ethz.ch
AF: Institute of Geophysics, and Geodesy and Geodynamics Lab ETH, Zurich, 8005 Switzerland
AU: * Goes, S
EM: saskia@tomo.ig.erdw.ethz.ch
AF: Institute of Geophysics, and Geodesy and Geodynamics Lab ETH, Zurich, 8005 Switzerland
AU: Giardini, D
AF: Institute of Geophysics, and Geodesy and Geodynamics Lab ETH, Zurich, 8005 Switzerland
AU: Hollenstein, C
AF: Institute of Geophysics, and Geodesy and Geodynamics Lab ETH, Zurich, 8005 Switzerland
AU: Kahle, H
AF: Institute of Geophysics, and Geodesy and Geodynamics Lab ETH, Zurich, 8005 Switzerland
AU: Geiger, A
AF: Institute of Geophysics, and Geodesy and Geodynamics Lab ETH, Zurich, 8005 Switzerland
AB: Subduction, collision and back-arc spreading zones within the Africa-European plate boundary meet in the south-central Mediterranean. Strain rate maps based on new geodetic data and existing seismic catalogs document several recent tectonic changes in this region. (1) Current Africa-European convergence around Sicily is localized north of the island, along what we interpret to be a back-arc thrust. This thrusting is a response to collision of the subduction zone with the African continental margin 1-3 Ma. Faults in west and central Sicily may be reactivated in occasional earthquakes, but do not accommodate significant compression anymore. (2) Back-arc extension in the Tyrrhenian is currently not observed. Within 1-2 mm/yr the area behaves like a rigid part of Europe. (3) There is no geodetic evidence of ongoing southeast migration of the Calabrian arc. (4) The Aeolian islands and northeastern Sicily exhibit an unusual and previously unrecognized velocity pattern. With velocities of up to two times Africa-European motions, this area is extending, and rotating relative to Africa. We suggest that mantle flow and gravitational collapse associated with an up-dip tearing between the Ionian and Sicilian portions of the slab are responsible for these unusual velocities. The tear could have developed when the trench collided with the Sicilian part of the African margin while roll-back at the Calabrian trench continued (until about 0.5 Ma). The existence of such a tear may also explain the occurrence of extensional earthquakes and high uplift rates in eastern Sicily, the location of Etna, and recent changes in the geochemical signature of Aeolian volcanism.
DE: 1206 Crustal movements--interplate (8155)
DE: 7230 Seismicity and seismotectonics
DE: 8123 Dynamics, seismotectonics
DE: 8150 Plate boundary--general (3040)
DE: 9335 Europe
SC: Tectonophysics [T]
MN: 2003 Fall Meeting