The area bounded by the Alpine chain to the North and Mediterranean/Ionian sea to the South is characterized by a wide range of tectonic phenomena, such as the identation of the Adria block into the Eastern Alp, lateral extrusion of the Tauern Window, unbending of the Adriatic lithosphere, opening of the Thyrrenian sea and subduction of the Ionian lithosphere beneath the Calabrian arc. This ongoing tectonics is accompanied by a relatively intense volcanism and seismicity, which justify the expectation of small but measurable horizontal and vertical displacements.
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Using the EUREF 97 velocities as a velocity datum, we have computed velocities of additional, permanent GPS stations in Italy from week 995 to week 1060 (30 January 1999 to 6 May 2000), and the components of a two dimensional, horizontal strain rate tensor. When examined in the context of independent geological, seismological and geophysical knowledge, the map of the geodetically inferred strain rate field shows several interesting correlation with fault plane solutions and the geometry of preexisting faults. Our kinematic model features an extensional regime on theLigurian and Thyrrenean sea, along and West of the Apennines, up to the Adria shore, and compression in the Friuli region. In the Channel of Sicily, the relative motion of Lampedusa and Noto results in an extension, which fits the aseismic deformation pattern in the Pantelleria Rift system. The maximum deformations occur in the Central Apennines, with and extensional strain rate of 27 10(-9) yr(-1) and in the Southern Appenines, with and extensional strain rate of 23 10(-9) yr(-1). In areas characterized by intense fracturing, and superposition of fault system with different attitudes and trends, the GPS station are to sparce to account for the short wavelenght changes in stress regime. This lack of spatial resolution is evident in the Western Po Plain, or in the Messina strait, where the regime clearly changes on a shorter scale than the average distans beteen the GPS stations in those areas. With these exceptions , we conclude that the information coming from the geodetic strain rate data fits the broad scale neotectonic pattern inferred from several large scale faults, fault plane solutions of recent, shallow earthquakes, and other geophysical indicators of the stress regime.
The paper presents application of the Geoweb system to the protection and reconstruction of dams, flood banks and road and railway embankments. It presents also installation of provisional dams and reinforcement of existing dams and embankments.
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