How to assess landslide activity and intensity with Persistent Scatterer Interferometry (PSI): the PSI-based matrix approach   总被引：5，自引：4，他引：1  

Francesca Cigna  Silvia Bianchini  Nicola Casagli 《Landslides》2013,10(3):267-283

We provide a step-by-step analysis and discussion of the ‘PSI-based matrix approach’, a methodology employing ground deformation velocities derived through Persistent Scatterer Interferometry (PSI) for the assessment of the state of activity and intensity of extremely to very slow landslides. Two matrices based on PSI data are designed respectively for landslides already mapped in preexisting inventories and for newly identified phenomena. Conversely, a unique intensity scale is proposed indiscriminately for both. Major influencing factors of the approach are brought to light by the application in the 14 km² area of Verbicaro, in Northern Calabria (Italy). These include lack of PSI data within the landslide boundaries, temporal coverage of the available estimates, and need of field checks as well as the operative procedures to set the activity and intensity thresholds. For the area of Verbicaro, we exploit 1992–2011 PSI data from ERS1/2 and RADARSAT1/2 satellites, projecting them along the maximum slope directions. An activity threshold of ±5 mm/year is determined by applying the average projection factor of local slopes to the PSI data precision. The intensity threshold between extremely and very slow phenomena (16 mm/year) is reduced by ~20 % to account for temporal and spatial averages being applied to attribute representative velocities to each landslide. The methodology allows assessing the state of activity and the intensity for 13 of the 24 landslides premapped in the 2007 inventory and for two newly identified phenomena. Current limitations due to characteristics and spatial coverage of PSI data are critically tackled within the discussion, jointly with respective implications.  相似文献   

Virtual tools for volcanic crisis management, and evacuation decision support: applications to El Chichón volcano (Chiapas, México)     

José Manuel Marrero  Alicia García  Angeles Llinares  Servando De la Cruz-Reyna  Silvia Ramos  Ramón Ortiz 《Natural Hazards》2013,68(2):955-980

Decision making regarding massive evacuation of a population threatened by a probable volcanic eruption is a major problem in crisis management. Such a decision is general on the number of people to be evacuated, available resources and infrastructure, quantity and quality of the escape routes and shelters, and the economic, social and political costs involved in the operation, coupled with the updated information provided by scientists about the forecast of future activity and probable eruption scenarios. Knowing time-lapse between the evacuation decision-making time and the time in which the evacuation is completed is another critical issue that must be carefully considered in densely populated areas. In such areas, it is really important to estimate in advance this time-lapse, as the forecast must be released with enough time to complete all the evacuation process before the destructive manifestations of the eruption begin. In this context, evacuation planning is a crucial component of emergency management. It is common for Emergency Plans to include pre-established strategies. However, an evacuation procedure should be flexible, depending on the above-mentioned timing, and on the decisions, evacuation schemes, environmental characteristics and other factors. In this work, several hazard models such as a lava flow model based on a Monte Carlo algorithm, a pyroclastic density current based on energy cone model, a semi-empirical inversion model to estimate the thickness of ash deposits, and all available information about the El Chión volcano have been used to obtain the area that should be evacuated in case of an eruption. Then, multiple evacuation strategies at El Chichón volcano have been designed, considering not only the characteristics of the eruption forecast, but also environmental factors (e.g., weather conditions) and social factors (e.g., tourism and farming seasons). The variable scale evacuation model has been used to estimate the evacuation time. In the paper, those virtual tools are briefly described as well as the information obtained from the drill of 2009. In addition to the optimization of evacuation under variable conditions and situations, one of the main objectives of this work is to provide a reliable estimation of the mitigation action time, for an Emergency Plan.  相似文献   

The interplanetary magnetic field environment at Mercury's orbit     

Haje Korth  Brian J. Anderson  Thomas H. Zurbuchen  James A. Slavin  Silvia Perri  Scott A. Boardsen  Daniel N. Baker  Sean C. Solomon  Ralph L. McNutt Jr. 《Planetary and Space Science》2011,59(15):2075-2085

Mercury is exposed to the most dynamic heliospheric space environment of any planet in the solar system. The magnetosphere is particularly sensitive to variations in the interplanetary magnetic field (IMF), which control the intensity and geometry of the magnetospheric current systems that are the dominant source of uncertainty in determinations of the internal planetary magnetic field structure. The Magnetometer on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has made extensive magnetic field observations in the inner heliosphere over the heliocentric distances of Mercury's orbit, between 0.31 and 0.47 AU. In this paper, Magnetometer data from MESSENGER, obtained at rates of 2 and 20 vector samples per second, are used together with previous observations in the inner heliosphere by Helios and at Earth by the Advanced Composition Explorer, to study the characteristics of IMF variability at Mercury's orbit. Although the average IMF geometry and magnitude depend on heliocentric distance as predicted by Parker, the variability is large, comparable to the total field magnitude. Using models for the external current systems we evaluate the impact of the variability on the field near the planet and find that the large IMF fluctuations should produce variations of the magnetospheric field of up to 30% of the dipole field at 200 km altitude, corresponding to the planned periapsis of MESSENGER's orbit at Mercury. The IMF fluctuations in the frequency range are consistent with turbulence, whereas evidence for dissipation was observed for . The transition between the turbulent and dissipative regimes is indicated by a break in the power spectrum, and the frequency of this break point is proportional to the IMF magnitude.  相似文献   

Ad hoc shared‐ride trip planning by mobile geosensor networks     

Stephan Winter  Silvia Nittel 《International journal of geographical information science》2013,27(8):899-916

Recent developments in miniaturization of computing devices, in location‐sensing technology and in ubiquitous short‐range wireless networks enable new types of social behaviour. This paper investigates one novel application of these technologies, ad hoc inner‐urban shared‐ride trip planning: Transportation clients such as pedestrians are seeking ad hoc shared rides from transportation hosts such as private automobiles, buses, taxi cabs or trains. While centralized trip planners are challenged by assigning clients and hosts in an ad hoc manner, in particular for non‐scheduled hosts, we consider the transportation network as a mobile geosensor network of agents that interact locally by short‐range communication and heuristic wayfinding strategies. This approach is not only fully scalable; we can also demonstrate that with short‐range communication, and hence, incomplete transportation network knowledge a system still can deliver near‐to‐optimal trips.  相似文献   

Real-time flood forecasting by relating local stage and remote discharge     

Silvia Barbetta  Tommaso Moramarco 《水文科学杂志》2013,58(9):1656-1674

Abstract

The rating curve model (RCM) proposed by Moramarco and co-authors is modified here for flood forecasting purposes without using rainfall information. The RCM is a simple approach for discharge assessment at a river site of interest based on relating the local recorded stage and the remote discharge monitored at an upstream gauged river site located some distance away. The proposed RCM for real-time application (RCM-RT), involves only two parameters and can be used for river reaches where significant lateral flows occur. The forecast lead time depends on the mean wave travel time of the reach. The model is found to be accurate for a long reach of the Po River (northern Italy) and for two branches of the Tiber River (central Italy) characterized by different intermediate drainage areas and wave travel times. Moreover, the assessment of the forecast uncertainty coming from the model parameters is investigated by performing a Monte Carlo simulation. Finally, the model capability to accurately forecast the exceedence of fixed hydrometric thresholds is analysed.

Editor D. Koutsoyiannis; Associate editor C. Perrin  相似文献   

A first estimation of tsunami hazard of the Pacific coast of Costa Rica from local and distant seismogenic sources     

Chacon-Barrantes  Silvia  Arozarena-Llopis  Isabel 《Ocean Dynamics》2021,71(8):793-810

Ocean Dynamics - Costa Rica has been affected by several local and distant tsunamis in the past, but the historical information is scarce and incomplete. Its Pacific coast stretches for over a...  相似文献   

B,V, and DDO photometric observations of red variable stars     

T. Storchi Bergmann  Silvia H. B. Livi  Roberto D. D. Costa 《Astrophysics and Space Science》1984,100(1-2):341-349

Light curves of the red variables L₂ Puppis, R Carinae, and S Carinae in the region of the spectrum covered by theB, V, and DDO photometry are presented. The behavior of the DDO color indices and their meaning for this type of star are discussed. S Carinae shows a different behavior from the other two stars that seems to be due to a population effect.  相似文献   

Le domaine Tariquide (arc de Gibraltar,Espagne et Maroc) : succession et hiatus de la sédimentation du Jurassique supérieur au Paléocène     

Michel Durand-Delga  Manuel Esteras  Silvia Gardin  Hélène Paquet 《Comptes Rendus Geoscience》2005,337(9):849-860

The originality of the Malm–Cretaceous series of the Tariquides (Gibraltar arc), as compared to those of the Rifian–Betic ‘Dorsale’ (Alboran domain), and especially with the Penibetic (Iberia) domain, is emphasized. In the Los Pastores Group, near Algeciras, Upper Tithonian nodular limestones directly lie on the Dogger and are followed by Aptychus-bearing limestones (Late Berriasian to Barremian). In the Musa Group, Rif, radiolarites are followed by siliceous limestones (Kimmeridgian–Tithonian), then by karst and massflow breccias connected to a Berriasian tectonics, by Aptychus-bearing marly limestones, then by karst filled by Turonian limestones, and finally by Maastrichtian–Palaeocene polychrome pelites, whose micropalaeontological and mineral compositions (clay minerals, FeMn nodules) refer to a deep-sea, probably infra-CCD, sedimentation. To cite this article: M. Durand-Delga et al., C. R. Geoscience 337 (2005).  相似文献   

XMM–Newton EPIC and Optical Monitor observations of Her X-1 over the 35-d beat period     

Silvia Zane  Gavin Ramsay  Mario A. Jimenez-Garate  Jan Willem den Herder  Charles J. Hailey 《Monthly notices of the Royal Astronomical Society》2004,350(2):506-516

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Cambro-Ordovician Magmatism in SE Brazil: U-Pb and Rb-Sr Ages, Combined with Sr and Nd Isotopic Data of Charnockitic Rocks from the Varzea Alegre Complex     

Julio Cezar Mendes  Silvia Regina de Medeiros  Ian McReath  Cristina Maria Pinheiro de Campos   《Gondwana Research》2005,8(3):337-345

In the central-southern region of Espírito Santo State, southeastern Brazil, several granitoids with a variable composition intruded high-grade metamorphic rocks, in the northern segment of the Ribeira fold belt. A close relationship between hydrous and anhydrous facies is present in some of the plutons, including the Varzea Alegre Igneous Complex, which has an inner domain formed by gabbro, diorite and granite, and an irregular outer ring of charnockitic rocks. These green megaporphyritic charnockites have primary anhydrous mineral assemblage, I-type and metaluminous character, and high-K calc-alkaline signature. U-Pb zircon single crystal ages obtained by TIMS indicate crystallization at about 500 Ma, similar to other late tectonic plutons of this part of the Ribeira belt. Sr and Nd isotopic ratios ranging from 0.7078 to 0.7096 and 0.5114 to 0.5116 respectively, are interpreted to be indicative of a hybrid origin from crustal and mantle-derived magmas. A binary diagram using Sr isotope ratios also demonstrates that the genesis of the charnockites probably included both magma mixing and fractional crystallization processes.  相似文献