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Galileian Plus S.r.L., Rome, Italy
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- PublicationOpen AccessFabric controls fault stability in serpentinite gouges(2023)
; ; ; ; ; ; ; ; ; ; ; ; ;Serpentinites are polymineralic rocks distributed almost ubiquitously across the globe in active tectonic regions. Magnetite-rich serpentinites are found in the low-strain domains of serpen- tinite shear zones, which act as potential sites of nucleation of unstable slip. To assess the potential of earthquake nucleation in these materials, we investigate the link between me- chanical properties and fabric of these rocks through a suite of laboratory shear experiments. Our experiments were done at room temperature and cover a range of normal stress and slip velocity from 25 to 100 MPa and 0.3 to 300 μm s −1 , respecti vel y. We show that magnetite-rich serpentinites are ideal materials since they display strong sensitivity to the loading rate and are susceptible to nucleation of unstable slip, especially at low forcing slip velocities. We also aim at the integration of mechanical and microstructural results to describe the underlying mechanisms that produce the macroscopic behaviour. We show that mineralogical composi- tion and mineral structure dictates the coexistence of two deformation mechanisms leading to stable and unstable slip. The weakness of phyllosilicates allows for creep during the interseis- mic phase of the laboratory seismic cycle while favouring the restoration of a load-bearing granular framework, responsible of the nucleation of unstable events. During dynamic slip, fault zone shear fabric determines the mode of slip, producing either asymmetric or Gaussian slip time functions for either fast or slow events. We report rate/state friction parameters and integrate our mechanical data with microstructural observations to shed light on the mech- anisms dictating the complexity of laborator y ear thquakes. We show that mineralogical and fabric heterogeneities control fault slip behaviour.87 11 - PublicationOpen AccessVolcanic Risk System (SRV): ASI Pilot Project to Support The Monitoring of Volcanic Risk In Italy by Means of EO Data(2008-11)
; ; ; ; ; ; ; ; ; ; ; ;Buongiorno, M. F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Musacchio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Zoffoli, S.; Agenzia Spaziale Italia, Rome, Italy ;Cardaci, C.; Dipartimento della Protezione Civile, Rome, Italy ;Sansosti, E.; CNR- Istituto per il Rilevamento Elettromagnetico dell’Ambiente Naples, Italy ;Vignoli, S.; Advanced Computer System S.p.A., Rome, Italy ;Amodio, A.; Galileian Plus S.r.L., Rome, Italy ;Pugnaghi, S.; Università degli Studi di Modena e Reggio Emilia, Modena, Italy ;Teggi, S.; Università degli Studi di Modena e Reggio Emilia, Modena, Italy ;Puglisi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Borgstrom, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; ; ; ; ; The ASI-SRV(Sistema Rischio Vulcanico) project started at the beginning of the 2007 is funded by the Italian Space Agency (ASI) in the frame of the National Space Plan 2003-2005 under the Earth Observations section for natural risks management. Coordinated by the Istituto Nazionale di Geofisica e Vulcanologia (INGV), which is responsible at national level for the volcanic monitoring, the project has as main objective to develop a pre-operative system based on EO data and ground measurements integration to support the volcanic risk monitoring of the Italian Civil Protection Department. The project philosophy is to implement specific modules which allow to process, store and visualize through Web GIS tools EO derived parameters considering three activity phases: 1) knowledge and prevention; 2) crisis; 3) post crisis. In order to combine effectively the EO data and the ground networks measurements the system will implement a multi-parametric analysis tool, which represents and unique tool to analyze contemporaneously a large data set of data in “near real time”. The SRV project will be tested his operational capabilities on three Italian Volcanoes: Etna,Vesuvio and Campi Flegrei.193 482 - PublicationRestrictedThe SISMA prototype system: integrating Geophysical Modeling and Earth Observation for time-dependent seismic hazard assessment(2011)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;An innovative approach to seismic hazard assessment is illustrated that, based on the available knowledge of the physical properties of the Earth structure and of seismic sources, on geodetic observations, as well as on the geophysical forward modeling, allows for a time-dependent definition of the seismic input. According to the proposed approach, a fully formalized system integrating Earth Observation data and new advanced methods in seismological and geophysical data analysis is currently under development in the framework of the Pilot Project SISMA, funded by the Italian Space Agency. The synergic use of geodetic Earth Observation data (EO) and Geophysical Forward Modeling deformation maps at the national scale complements the space- and time-dependent information provided by real-time monitoring of seismic flow (performed by means of the earthquake prediction algorithms CN and M8S) and permits the identification and routine updating of alerted areas. At the local spatial scale (tens of km) of the seismogenic nodes identified by pattern-recognition analysis, both GNSS (Global Navigation Satellite System) and SAR (Synthetic Aperture Radar) techniques, coupled with expressly developed models for interseismic phase, allow us to retrieve the deformation style and stress evolution within the seismogenic areas. The displacement fields obtained from EO data provide the input for the geophysical modeling, which eventually permits to indicate whether a specific fault is in a “critical state.” The scenarios of expected ground motion (shakemaps) associated with the alerted areas are then defined by means of full waveforms modeling, based on the possibility to compute synthetic seismograms by the modal summation technique (neo-deterministic hazard assessment). In this way, a set of deterministic scenarios of ground motion, which refer to the time interval when a strong event is likely to occur within the alerted area, can be defined both at national and at local scale. The considered integrated approach opens new routes in understanding the dynamics of fault zones as well as in modeling the expected ground motion. The SISMA system, in fact, provides tools for establishing warning criteria based on deterministic and rigorous forward geophysical models and hence allows for a well-controlled real-time prospective testing and validation of the proposed methodology over the Italian territory. The proposed approach complements the traditional probabilistic approach for seismic hazard estimates, since it supplies routinely updated information useful in assigning priorities for timely mitigation actions and hence it is particularly relevant to Civil Defense purposes.82 1