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Centro Ricerche Sismologiche, Udine, Italy.
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- PublicationRestrictedHydrologically induced slope deformations detected by GPS and clinometric surveys in the Cansiglio Plateau, southern Alps(2015-03-31)
; ; ; ; ; ;Devoti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Zuliani, D.; Centro Ricerche Sismologiche, OGS, Udine ;Braitenberg, C.; Dip. di Matematica e Geoscienze, Università di Trieste ;Fabris, P.; Centro Ricerche Sismologiche, OGS, Udine ;Grillo, B.; Dip. di Matematica e Geoscienze, Università di Trieste; ; ; ; Changes in groundwater or surface water level may cause observable deformation of the drainage basins in different ways. We describe an active slope deformation monitored with GPS and tiltmeter stations in a karstic limestone plateau in southeastern Alps (Cansiglio Plateau). The observed transient GPS deformation clearly correlates with the rainfall. Both GPS and tiltmeter equipments react instantly to heavy rains displaying abrupt offsets, but with different time constants, demonstrating the response to different catchment volumes. The GPS movement is mostly confined in the horizontal plane (SSW direction) showing a systematic tendency to rebound in the weeks following the rain. Four GPS stations concur to define a coherent deformation pattern of a wide area (12 × 5 km2), concerning the whole southeastern slope of the plateau. The plateau expands and rebounds radially after rain by an amount up to a few centimeters and causing only small vertical deformation. The effect is largest where karstic features are mostly developed, at the margin of the plateau where a thick succession of Cretaceous peritidal carbonates faces the Venetian lowland. Acouple of tiltmeters installed in a cave at the top of the plateau, detect a much faster deformation, that has the tendency to rebound in less than 6h. The correlation to rainfall is less straightforward, and shows a more complex behavior during rainy weather. The different responses demonstrate a fast hydrologic flow in the more permeable epikarst for the tiltmeters, drained by open fractures and fissures in the neighborhood of the cave, and a rapid tensile dislocation of the bedrock measured at the GPS stations that affect the whole slope of the mountain. In the days following the rain, both tiltmeter and GPS data show a tendency to retrieve the displacement which is consistent with the phreatic discharge curve. We propose that hydrologically active fractures recharged by rainfall are the most likely features capable to induce the observed strain variations.509 86 - PublicationOpen AccessACQUIRING SEISMIC DATA IN THE NORTH-EAST OF ITALY: THE OGS-CRS EXPERIENCE IN USING THE ANTELOPE SOFTWARE SUITE(2006)
; ; ; ; ; ; ; ;Pesaresi, D.; IST. NAZ. GEOFISICA E VULCANOLOGIA ;Bragato, P. L.; IST. NAZ. DI OCEONOGRAFIA E DI GEOFISICA SPERI. ;Di Bartolomeo, P.; IST. NAZ. DI OCEONOGRAFIA E DI GEOFISICA SPERI. ;Durì, G.; IST. NAZ. DI OCEONOGRAFIA E DI GEOFISICA SPERI. ;Govoni, A.; IST. NAZ. GEOFISICA E VULCANOLOGIA ;Ponton, F.; IST. NAZ. DI OCEONOGRAFIA E DI GEOFISICA SPERI. ;Zuliani, D.; IST. NAZ. DI OCEONOGRAFIA E DI GEOFISICA SPERI.; ; ; ; ; ; NO129 716 - PublicationRestrictedStrain accumulation in the southern Alps (NE Italy) and deformation(2005-10-14)
; ; ; ; ; ; ;D'Agostino, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Cheloni, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Mantenuto, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Selvaggi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Michelini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Zuliani, D.; Centro Ricerche Sismologiche, Udine, Italy.; ; ; ; ; We use continuous GPS observations to investigate the rate of strain accumulation in the area affected by the 1976 Friuli earthquakes. Comparison between the motion predicted by the rigid-rotation of Adria and the shortening observed across the study area suggests that the 2.0 ± 0.2 mm/yr motion of Adria is entirely absorbed in the southern Alps through thrusting and crustal thickening with very little or no motion transferred to the north.We use elastic dislocation modelling to investigate the rate of interseismic loading and the geometry of the shear zone at depth. The best-fit solution indicates that a northward-dipping creeping dislocation, whose edge is located within a 50 km wide area beneath the southern Alps, accomodates 2.1 ± 0.5 mm/yr of the Adria motion. Limited resolution on locking depth (acceptable values between 0 and 25 km) and trade-off between dip and slip do not allow a precise reconstruction of the dislocation geometry. The range of acceptable model parameters is consistent with a 20 -dipping dislocation, locked above 10 km depth and slipping at 2.4 mm/yr, whose geometry is suggested by seismological informations.199 18