Characterizing and Predicting Traffic Accidents in Extreme Weather Environments     

Richard M. Medina  Guido Cervone  Nigel M. Waters 《The Professional geographer》2017,69(1):126-137

Motorists are vulnerable to extreme weather events, which are likely to be exacerbated by climate change throughout the world. Traffic accidents are conceptualized in this article as the result of a systemic failure that includes human, vehicular, and environmental factors. The snowstorm and concurrent accidents that occurred in the Northeastern United States on 26 January 2011 are used as a case study. Traffic accident data for Fairfax County, Virginia, are supplemented with Doppler radar and additional weather data to characterize the spatiotemporal patterns of the accidents resulting from this major snowstorm event. A kernel density smoothing method is implemented to identify and predict patterns of accident locations within this urban area over time. The predictive capability of this model increases over time with increasing accidents. Models such as these can be used by emergency responders to identify, plan for, and mitigate areas that are more susceptible to increased risk resulting from extreme weather events.  相似文献   

Hydrological connectivity of alluvial Andean valleys: a groundwater/surface-water interaction case study in Ecuador     

Pablo Guzmán  Christian Anibas  Okke Batelaan  Marijke Huysmans  Guido Wyseure 《Hydrogeology Journal》2016,24(4):955-969

The Andean region is characterized by important intramontane alluvial and glacial valleys; a typical example is the Tarqui alluvial plain, Ecuador. Such valley plains are densely populated and/or very attractive for urban and infrastructural development. Their aquifers offer opportunities for the required water resources. Groundwater/surface-water (GW–SW) interaction generally entails recharge to or discharge from the aquifer, dependent on the hydraulic connection between surface water and groundwater. Since GW–SW interaction in Andean catchments has hardly been addressed, the objectives of this study are to investigate GW–SW interaction in the Tarqui alluvial plain and to understand the role of the morphology of the alluvial valley in the hydrological response and in the hydrological connection between hillslopes and the aquifers in the valley floor. This study is based on extensive field measurements, groundwater-flow modelling and the application of temperature as a groundwater tracer. Results show that the morphological conditions of a valley influence GW–SW interaction. Gaining and losing river sections are observed in narrow and wide alluvial valley sections, respectively. Modelling shows a strong hydrological connectivity between the hillslopes and the alluvial valley; up to 92 % of recharge of the alluvial deposits originates from lateral flow from the hillslopes. The alluvial plain forms a buffer or transition zone for the river as it sustains a gradual flow from the hills to the river. Future land-use planning and development should include concepts discussed in this study, such as hydrological connectivity, in order to better evaluate impact assessments on water resources and aquatic ecosystems.  相似文献   

Suspended sediment transport analysis in two Italian instrumented catchments   总被引：2，自引：1，他引：1  

Adriana García-Rama  Stefano Giorgio Pagano  Francesco Gentile  Mario Aristide Lenzi 《山地科学学报》2016,13(6):957-970

Suspended sediment transport in streams is an effective indicator of soil erosion at the watershed scale. This process was studied using the data obtained from two continuous monitoring stations installed in Italian watersheds, the Rio Cordon and Torrente Carapelle. The catchments have substantially different climatic, morphological and land use characteristics. The Rio Cordon, a small Alpine watershed, has been monitored since 1986, while in the Torrente Carapelle, a medium-size Mediterranean watershed, the monitoring station has provided data since 2007. Several flood events with suspended sediment transport were isolated in the two catchments, excluding those determined by snowmelt in the Rio Cordon as this process does not affect the Carapelle watershed. Analysis of the events showed different behavior in terms of hysteresis loop trends between water discharge (m³ s^-1) and suspended sediment concentration (g l^-1) values, as the Rio Cordon confirms clockwise relationships most frequently, while counter-clockwise trends represent the majority of cases for the Carapelle Torrent. The different behavior of the two watersheds was further analyzed by evaluating relationships between the main hydrological parameters related to suspended sediment transport. Runoff controls the total sediment budget in both catchments. In contrast, it was noted that the runoff process does not interfere in the magnitude of the suspended sediment transport in the Rio Cordon catchment, while variations due to the larger size of the catchment area characterize the events in the Carapelle watershed. Lastly, a flow peak threshold that determines the advance or delay of the hydrograph peak with respect to the sedigraph peak was established for the Carapelle Torrent, while it was not reported in the Rio Cordon.  相似文献   

Potential effects of climate changes on soil–atmosphere interaction and landslide hazard     

Guido Rianna  Luca Comegna  Paola Mercogliano  Luciano Picarelli 《Natural Hazards》2016,84(2):1487-1499

  相似文献   

Kinematic significance of mingling-rolling structures in lava flows: a case study from Porri Volcano (Salina, Southern Tyrrhenian Sea)     

Guido Ventura 《Bulletin of Volcanology》1998,59(6):394-403

 A basaltic andesite lava flow from Porri Volcano (Salina, Southern Tyrrhenian Sea) is composed of two different magmas. Magma A (51 vol.% of crystals) has a dacitic glass composition, and magma B (18 vol.% of crystals), a basaltic glass composition. Magma B is hosted in A and consists of sub-spherical enclaves and boudin-like, banding and rolling structures (RS). Four types of RS have been recognized: σ–type;δ–type; complex σ-δ–types and transitional structures between sub-spherical enclaves and rolling structures. An analysis of the RS has been performed in order to reconstruct the flow kinematics and the mechanism of flow emplacement. Rolling structures have been selected in three sites located at different distances from the vent. In all sites most RS show the same sense of shear. Kinematic analysis of RS allows the degree of flow non-coaxiality to be determined. The non-coaxiality is expressed by the kinematic vorticity number Wk, a measure of the ratio Sr between pure shear strain rate and simple shear strain rate. The values of Wk calculated from the measured shapes of microscopic RS increase with increasing distance from the vent, from approximately 0.5 to 0.9. Results of the structural analysis reveal that the RS formed during the early–intermediate stage of flow emplacement. They represent originally sub-spherical enclaves deformed at low shear strain. At higher strain, RS deformed to give boudin-like and stretched banding structures. Results of the kinematic analysis suggest that high viscosity lava flows are heterogeneous non-ideal shear flows in which the degree of non-coaxiality increases with the distance from the vent. In the vent area, deformation is intermediate between simple shear and pure shear. Farther from the vent, deformation approaches ideal simple shear. Lateral extension processes occur only in the near-vent zone, where they develop in response to the lateral push of magma extruded from the vent. Lateral shortening processes develop in the distal zone and record the gravity-driven movement of the lava. The lava flow advanced by two main mechanisms, lateral translation and rolling motion. Lateral translation equals rolling near the vent, while rolling motion prevailed in the distal zones. Received: 6 November 1997 / Accepted: 29 November 1997  相似文献   

Mechanisms for ground-surface fracturing and incipient slope failure associated with the 2001 eruption of Mt. Etna, Italy: analysis of ephemeral field data     

Andrea Billi  Valerio Acocella  Renato Funiciello  Guido Giordano  Gianni Lanzafame  Marco Neri 《Journal of Volcanology and Geothermal Research》2003,122(3-4):281-294

During the July–August 2001 eruption of Mt. Etna development of extensional fractures/faults and grabens accompanied magma intrusion and subsequent volcanic activity. During the first days of the eruption, we performed an analysis of attitude, displacement and propagation of fractures and faults exposed on the ground surface in two sites, Torre del Filosofo and Valle del Leone, located along the same fracture system in the region surrounding the Valle del Bove depression on the eastern flank of Mt. Etna. Fractures and faults formed as the consequence of a shallow intruding dyke system that fed the several volcanic centres developed along the fracture system. The investigated sites differ in slope attitude and in geometrical relationships between fractures and slopes. In particular, the fracture system propagated parallel to the gentle slope (<7° dip) in the Torre del Filosofo area, and perpendicular to the steep slope (25° dip) in the Valle del Leone area. In the Torre del Filosofo area, slight graben subsidence and horizontal extension of the ground surface by about 3 m were recorded. In the Valle del Leone area, extensional faulting forming a larger and deeper graben with horizontal extension of the ground surface by about 10 m was recorded. For the Valle del Leone area, we assessed a downhill dip of 14° for the graben master fault at the structural level beneath the graben where the fault dip shallows. These results suggest that dyke intrusion at Mount Etna, and particularly in the region surrounding the Valle del Bove depression, may be at the origin of slope failure and subsequent slumps where boundary conditions, i.e. geometry of dyke, slope dip and initial shear stress, amongst others, favour incipient failures.  相似文献   

Risk assessment of bottom ash from fuel oil power plant of Italy: mineralogical,chemical and leaching characterization     

M. Di Bella  F. Italiano  S. Magazù  A. F. Mottese  M. Interdonato  F. Gentile  G. Sabatino 《Environmental Earth Sciences》2018,77(5):217

The main aim of the present study is to contribute to the field of environmental research by providing new data on bottom ash samples derived from an oil power plant located in Southern Italy. To achieve this purpose, the mineralogical and chemical properties of representative bottom ash samples were investigated through the integrated employment of different analytical techniques, i.e., X-ray powder diffraction, scanning electron microscopy, X-ray fluorescence and atomic absorption spectrometry. The obtained experimental results show that quartz, alunogen, rhomboclase and potassium hydrogen silicate are the major crystalline phases of all the analyzed samples. Furthermore, the revealed main ash constituents are SiO₂ and SO₃, with low contents of Fe₂O₃ and Al₂O₃, and little amounts of CaO, Na₂O, K₂O, MgO, P₂O₅ and TiO₂. Among the trace elements, very high amounts of heavy metals, i.e., V, Cr, Ni, La, Pb and Mo, were detected. The comparison of the obtained heavy metal abundance data with those reported in the literature highlights significant differences. Leaching test evidenced V, Ni and Cr values that make these ashes a potential contamination source for groundwater quality and for soil, nearby the ash disposal landfills area. All the obtained findings show that these materials are highly harmful for the human health, with a greater extent for the heavy metal concentrations.  相似文献   

Simulating Oxygen Intrusion into Highly Heterogeneous Fractured Media Using High Performance Computing     

Paolo Trinchero  Jorge Molinero  Hedieh Ebrahimi  Ignasi Puigdomenech  Björn Gylling  Urban Svensson  Dirk Bosbach  Guido Deissmann 《Mathematical Geosciences》2018,50(5):549-567

Fractured crystalline rocks are under consideration by several countries as host formations for high-level nuclear waste repositories. The redox evolution in these host rock formations is an important issue for the stability and safety of these disposal sites. If, for example, during a glaciation/deglaciation event, oxygen-rich glacial meltwater penetrates to the depth of the planned repository, some of the engineered barriers would be adversely affected. Moreover, oxidizing conditions would increase the solubility and mobility of many radionuclides. Reactive transport simulations, which are typically used to assess the redox buffering capacity of these host rock formations, are computationally demanding, and thus, calculations for the evaluation of oxygen penetration are usually carried out over simplified geometries and the heterogeneity of the site, both physical (e.g., variability in the groundwater flow field and the kinematic porosity) and mineralogical (e.g., variability in the abundance of Fe(II)-bearing minerals), is usually represented in a simplified fashion. Here, it is shown how a recently developed numerical framework, combined with high performance computing technologies, allows the full geometrical, physical and mineralogical complexity of the site under study to be efficiently included in these types of reactive transport calculations. A synthetically generated realistic three-dimensional fractured medium is used to assess oxygen penetration patterns and their dependence on both the hydrogeological conditions and the availability of Fe(II)-bearing minerals. The results of the calculations point out the significant influence of both physical and mineralogical heterogeneity on the oxygen penetration patterns, thus highlighting the importance of a model parameterisation consistent with the site complexity.  相似文献   

Benchmarking the software packages to model and assess the seismic response of unreinforced masonry existing buildings through nonlinear static analyses     

Cattari  Serena  Magenes  Guido 《Bulletin of Earthquake Engineering》2022,20(4):1901-1936

Bulletin of Earthquake Engineering - Seismic modelling of unreinforced masonry (URM) buildings is addressed worldwide according to different approaches, not only at research level, but also in the...  相似文献   

Nonlinear modeling of the seismic response of masonry structures: critical review and open issues towards engineering practice     

Cattari  Serena  Calderoni  Bruno  Cali&#;  Ivo  Camata  Guido  de Miranda  Stefano  Magenes  Guido  Milani  Gabriele  Saetta  Anna 《Bulletin of Earthquake Engineering》2022,20(4):1939-1997

Bulletin of Earthquake Engineering - This paper provides a comphrensive review of the critical aspects of nonlinear modeling for evaluating the seismic response of masonry structures, emphasizing...  相似文献