HR: 0800h
AN: G21B-1276    [Abstracts]
TI: Adriatic Tectonics: Rigorous Tests of Present-Day Plate Motion Using Continuous GPS
AU: * Freemantle, A
EM: anna.freemantle@ncl.ac.uk
AF: School of Civil Engineering and Geosciences, Cassie Building, University of Newcastle, Newcastle upon Tyne, NE1 7RU United Kingdom
AU: Clarke, P
EM: peter.clarke@newcastle.ac.uk
AF: School of Civil Engineering and Geosciences, Cassie Building, University of Newcastle, Newcastle upon Tyne, NE1 7RU United Kingdom
AU: King, M
EM: m.a.king@ncl.ac.uk
AF: School of Civil Engineering and Geosciences, Cassie Building, University of Newcastle, Newcastle upon Tyne, NE1 7RU United Kingdom
AU: Lavallée, D
EM: d.a.lavallee@ncl.ac.uk
AF: School of Civil Engineering and Geosciences, Cassie Building, University of Newcastle, Newcastle upon Tyne, NE1 7RU United Kingdom
AB: The Mediterranean region is of active research interest due to the high level of recent and historical seismicity (several high-magnitude earthquakes within the last century). The Adriatic microplate lies within a collisional environment caused by the northward motion of the African tectonic plate and its subduction under the Eurasian plate. A key question is whether the Adriatic microplate is a rigid promontory of the African plate and hence mirrors its behaviour, or if it is moving independently, either rigidly in one or more parts, or with some distributed deformation. The use of continuous GPS networks within the region can give precise directions and rates of motion in a global reference frame. Using several years of data, plate motion models can be tested using rigorous estimates of velocity errors that account for time-correlated noise characteristics and the presence of seasonal signals. 105 global and European GPS sites, incorporating ~40 sites within the Adriatic region including the Friuli Regional Deformation Network (FReDNet) and the Venice Network (Venezia Consorzio Nuova), have been processed for the period 1999-2004 using GIPSY fiducial-free Precise Point Positioning. We have obtained rigorous estimates of the ITRF2000 velocities and their confidence limits using the CATS time series analysis software. Error estimates are increased by up to one order of magnitude compared with those based on linear motion, white noise, assumptions. We derive plate rotation rates and test the compatibility of site velocities within the Adriatic region with African and local (microplate) motions. Northern Adriatic sites do not exhibit African plate velocities, but the transition to African motion further south remains ill-defined. We compare strain rates across this zone with recent seismicity.
DE: 1209 Tectonic deformation (6924)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Geodesy [G]
MN: Fall Meeting 2005