Tier-based approaches for landslide susceptibility assessment in Europe   总被引：3，自引：2，他引：1  

Andreas Günther  Paola Reichenbach  Jean-Philippe Malet  Miet Van Den Eeckhaut  Javier Hervás  Claire Dashwood  Fausto Guzzetti 《Landslides》2013,10(5):529-546

In the framework of the European Soil Thematic Strategy and the associated proposal of a Framework Directive on the protection and sustainable use of soil, landslides were recognised as a soil threat requiring specific strategies for priority area identification, spatial hazard assessment and management. This contribution outlines the general specifications for nested, Tier-based geographical landslide zonings at small spatial scales to identify priority areas susceptible to landslides (Tier 1) and to perform quantitative susceptibility evaluations within these (Tier 2). A heuristic, synoptic-scale Tier 1 assessment exploiting a reduced set of geoenvironmental factors derived from common pan-European data sources is proposed for the European Union and adjacent countries. Evaluation of the susceptibility estimate with national-level landslide inventory data suggests that a zonation of Europe according to, e.g. morphology and climate, and performing separate susceptibility assessments per zone could give more reliable results. To improve the Tier 1 assessment, a geomorphological terrain zoning and landslide typology differentiation are then applied for France. A multivariate landslide susceptibility assessment using additional information on landslide conditioning and triggering factors, together with a historical catalogue of landslides, is proposed for Tier 2 analysis. An approach is tested for priority areas in Italy using small administrative mapping units, allowing for relating socioeconomic census data with landslide susceptibility, which is mandatory for decision making regarding the adoption of landslide prevention and mitigation measures. The paper concludes with recommendations on further work to harmonise European landslide susceptibility assessments in the context of the European Soil Thematic Strategy.  相似文献   

The influence of variable topography on the depositional behaviour of pyroclastic density currents: The examples of the Upper Pollara eruption (Salina Island,southern Italy)     

Roberto Sulpizio  Rosanna De Rosa  Paola Donato 《Journal of Volcanology and Geothermal Research》2008

Stratigraphic reconstruction of the Upper Pollara eruption has allowed for the inference of eruptive mechanisms and the distillation of a sedimentological model for pyroclastic density currents (PDCs) moving across variable topography. The pre-eruptive topography in the study area was characterised by a tuff ring-like morphology, with both inward and outward dipping slopes. Highly viscous, moderately porphyritic, dacitic to rhyolitic magmas fed the eruption, which was characterised by a Vulcanian eruptive style. The stratigraphic succession was divided into five eruption units (EUs), which result from different phases of the eruption separated by stases. Sustained columns occurred only during EU1, while PDC generation dominates EU2–5. Lithofacies analysis of the PDC deposits indicates the prevalence of massive coarse-grained deposits on the inner slopes of the Pollara crater, which are interpreted as the deposits of a flow-boundary zone dominated by granular flow or fluid escape regimes. Dune-bedded, massive to stratified lithofacies dominate the outer slopes of the Pollara crater, and are interpreted as the deposits of PDCs with flow-boundary zones in which traction played a major role. Thin, massive PDC deposits are exposed on the sub-horizontal Malfa terrace, and are interpreted as representative of flow-boundary zones dominated by a granular flow regime. The occurrence of stacked deposits indicates that most of the PDCs were characterised by unsteady pulsatory behaviour, with development of trains of pulses during their transport. The downcurrent lithofacies transitions observed for the Upper Pollara deposits have finally been compared with other similar lithofacies associations which have been described for short-lived PDCs at tuff rings, in order to discuss the influence of pre-eruptive topography on lithofacies association.  相似文献   

Flexural deformation controls on Late Quaternary sediment dispersal in the Garo-Rajmahal Gap,NW Bengal Basin     

Jean-Louis Grimaud  Celine Grall  Steven Goodbred  Michael S. Steckler  Ryan Sincavage  Jennifer L. Pickering  Chris Paola  Leonardo Seeber  Md. Saddam Hossain 《Basin Research》2020,32(5):1242-1260

Subsurface deformation is a driver for river path selection when deformation rates become comparable to the autogenic mobility rate of rivers. Here we combine geomorphology, soil and sediment facies analyses, and geophysical data of the Late Quaternary sediments of the central Garo-Rajmahal Gap in Northwest Bengal to link subsurface deformation with surface processes. We show variable sedimentation characteristics, from slow rates (<0.8 mm/year) in the Tista megafan at the foot of the Himalaya to nondeposition at the exposed surface of the Barind Tract to the south, enabling the development of mature soils. Combined subsidence in the Tista fan and uplift of the Barind Tract are consistent with a N-S flexural response of the Indian plate to loading of the Himalaya Mountains given a low value of elastic thickness (15–25 km). Provenance analysis based on bulk strontium concentration suggests a dispersal of sediment consistent with this flexural deformation—in particular the abandonment of the Barind Tract by a Pleistocene Brahmaputra River and the current extents of the Tista megafan lobes. Overall, these results highlight the control by deeply rooted deformation patterns on the routing of sediment by large rivers in foreland settings.  相似文献   

Topographic effects observed at Amatrice hill during the 2016-2017 Central Italy seismic sequence     

Gerardo Grelle  Laura Bonito  Maresca Rosalba  Silvia Iacurto  Claudia Madiai  Paola Revellino  Giuseppe Sappa 《地震工程与工程振动(英文版)》2021,20(1):63-78

The estimate of seismic site effects by experimental approaches is based on different assumptions aimed at simplifying the complex actual site conditions and related uncertainties.However,the reliability of the results can increase if the experimental data is focused on quite strong seismic sequences and the on-site acquisition of a large number of signals is deemed strategic for the assessment of the expected phenomena.Based on these considerations,the ground motion at the Red Zone sector of Amatrice hill,violently struck by the 2016-2017 Central Italy seismic sequence,was analyzed via an observational approach.A large set of weak motions(moment magnitude Mw 2.5-3.9)was analyzed in this study by means of standard(SSR)and horizontal to vertical(HVSR)spectral ratio techniques.The results from the experimental analysis of the site effects by using weak motion and noise signals show a significant amplification at the top of Amatrice hill with a remarkable polarization of the motion and changes in spectral shapes according to the topographic setting of the relief.  相似文献   

Relict sand dredging for beach nourishment in the central Tyrrhenian Sea (Italy): effects on benthic assemblages     

Barbara La Porta  Monica Targusi  Loretta Lattanzi  Paola La Valle  Daniela Paganelli  & Luisa Nicoletti 《Marine Ecology》2009,30(S1):97-104

The aim of this study is to analyse the effects in space and time of relict sand-dredging activities on macrobenthic assemblages, in an area situated offshore Montalto di Castro (central Tyrrhenian Sea, Italy), and to analyse the recolonisation processes of macrobenthos in the dredged areas. The area in question is characterised by relict sand deposits (Holocenic paleo-beaches), used for beach nourishment along the Latium coast. The effects of sand extraction on benthic assemblages were investigated before, during and after three dredging operations. The sites analysed are located within the dredged areas (inside stations) and in neighbouring, not dredged, areas (outside stations). The results showed that the impact of sand extraction was confined to the dredged stations and to the areas in proximity to the dredged areas. During dredging activities, the structure of benthic assemblages within the impacted stations was characterised by low species richness and diversity. Both the direct removal of sediment and the re-suspension and consequent deposition of fine sediment affected benthic assemblages of the impacted stations. A few months after the dredgings, a recolonisation process was still observed at all the impacted stations. A gradual recolonisation process was observed at those stations affected by only one dredging, whereas a different recolonisation was observed at those stations affected by two dredgings over time. This study suggests that differences of re-colonisation processes of benthic assemblages are related to the intensity of dredging operations in terms of dredging frequency.  相似文献   

Provenance of deep-water reservoir sandstones from the Jubarte oil field,Campos Basin,Eastern Brazilian Margin     

Paola De Rossi Fontanelli  Luiz Fernando De Ros  Marcus Vinicius Dorneles Remus 《Marine and Petroleum Geology》2009

The provenance of the Maastrichtian deep-water reservoir sandstones from the Jubarte oil field (Campos Basin, eastern Brazil), was studied using an integrated approach that included quantitative petrography, conventional heavy mineral analysis, garnet mineral chemistry and zircon geochronology. The reservoirs are predominantly coarse, poorly-sorted sandstones with feldspathic composition derived from uplifted basement terrains. The fourth- and fifth-order depositional sequences analyzed show no major variations in composition or in provenance through time. However, variations in apatite:tourmaline presents potential to be used as a parameter for sandstone correlation within the field. The composition of heavy minerals indicates derivation from high temperature and low-to-medium pressure aluminous metapelitic rocks, from granites and subordinate mafic rocks, derived from the Cabo Frio Tectonic Domain and the Oriental terrain of Ribeira orogen, characterizing a supply route from SW to NE. The low ZTR index, as well as the absence of low-grade stable heavy minerals and of metasedimentary rock fragments, suggest that by the end of Cretaceous all supracrustal, low-grade terrains had already been totally eroded, and that plutonic, infracrustal rocks were exposed, similarly to the present situation.  相似文献   

Pairs of pulsars (PSR) and the origin of PSR     

Massimo Fracassini  Paola Maggi  Laura E. Pasinetti 《Astrophysics and Space Science》1986,128(2):363-368

The results of research on pairs of PSR which were possibly components of disrupted binaries, seem to advance further arguments in favour of the idea, suggested by some authors, that most of PSR were formed in binary systems.  相似文献   

Sources of M_w 5+ earthquakes in northeastern Italy and western Slovenia: An updated view based on geological and seismological evidence     

Pierfrancesco Burrato  Maria Eliana Poli  Paola Vannoli  Adriano Zanferrari  Roberto Basili  Fabrizio Galadini 《Tectonophysics》2008,453(1-4):157

We present an overview of the seismogenic sources of northeastern Italy and western Slovenia, included in the last version of the Database of Individual Seismogenic Sources (DISS 3.0.2) and a new definition of the geometry of the Montello Source that will be included in the next release of the database. The seismogenic sources included in DISS are active faults capable of generating M_w > 5.5 earthquakes. We describe the method and the data used for their identification and characterization, discuss some implications for the seismic hazard and underline controversial points and open issues.In the Veneto–Friuli area (NE Italy), destructive earthquakes up to M_w 6.6 are generated by thrust faulting along N-dipping structures of the Eastern Southalpine Chain. Thrusting along the mountain front responds to about 2 mm/a of regional convergence, and it is associated with growing anticlines, tilted and uplifted Quaternary palaeolandsurfaces and forced drainage anomalies. In western Slovenia, dextral strike–slip faulting along the NW–SE trending structures of the Idrija Fault System dominates the seismic release. Activity and style of faulting are defined by recent earthquakes (e.g. the M_s 5.7, 1998 Bovec–Krn Mt. and the M_w 5.2, 2004 Kobarid earthquakes), while the related recent morphotectonic imprint is still a debated matter.We reinterpreted a large set of tectonic data and developed a segmentation model for the outermost Eastern Southalpine Chain thrust front. We also proposed the association of the four major shocks of the 1976 Friuli earthquake sequence with individual segments of three major thrust fronts. Although several sub-parallel active strike–slip strands exist in western Slovenia, we were able to positively identify only two segments of the Idrija Fault System. A comparison of the regional GPS velocity with long-term geological slip-rates of the seismogenic sources included in DISS shows that from a quarter to half of the deformation is absorbed along the external alignment of thrust faults in Veneto and western Friuli. The partitioning of the deformation in western Slovenia among the different strike–slip strands could not be quantified.  相似文献   

Pressure dependence of structural parameters of paragonite     

Paola Comodi  Pier Francesco Zanazzi 《Physics and Chemistry of Minerals》1997,24(4):274-280

The compressibility and structure of a 2M₁ paragonite with composition [Na_0.88K_0.10Ca_0.01Ba_0.01] [Al_1.97Ti_0.007Fe_0.01Mn_0.002Mg_0.006]Si_3.01Al_0.99O₁₀OH₂ were determined at pressures between 1 bar and 41 kbar, by single crystal X-ray diffraction using a Merrill-Bassett diamond anvil cell. Compressibility turned out to be largely anisotropic, linear compressibility coefficients parallel to the unit cell edges being β_a=3.5(1)·10^?4, β_b=3.6(1)·10^?4, β_c=8.3(3)·10^?4 kbar^?1 (β_a:β_b·β_c=1:1028:2.371). The isothermal bulk modulus, calculated as the reciprocal of the mean compressibility of the cell volume, was 650(20) kbar. The main features of the deformation mechanism resulting from structural refinements at pressures of 0.5, 25.4, 40.5 kbar were: –?variation in sheet thickness, showing that compression of the c parameter was mainly due to the interlayer thickness reduction from 3.07 Å at 0.5 kbar to 2.81 Å at 40.5 kbar; –?the compressibility of octahedra was greater than that of tetrahedra, the dimensional misfit between tetrahedral and octahedral sheets increased with P, so that tetrahedral rotation angel α increased from 15° at 0.5 kbar to 21.6° at 40.5 kbar; –?the basal surface corrugation (Δz) of the tetrahedral layer, due to the different dimensions of M1 and M2 octahedra and to the octahedral distortion, decreased with P (Δz=0.19 and 0.12 Å at 0.5 and 40.5 kbar respectively). Comparison of the new data on paragonite with those of a K-muscovite and a Na-rich muscovite (Comodi and Zanazzi 1995) revealed a clear trend toward decreasing of compressibility when Na substitutes for K atoms in the interlayer sites.  相似文献   

An Innovative Approach to Meteorite Analysis by Laser‐Induced Breakdown Spectroscopy          下载免费PDF全文

Giorgio S. Senesi  Gioacchino Tempesta  Paola Manzari  Giovanna Agrosì 《Geostandards and Geoanalytical Research》2016,40(4):533-541

An innovative approach of double pulse laser‐induced breakdown spectroscopy (DP‐LIBS) coupled with optical microscopy was applied to the characterisation and quantitative analysis of the Agoudal iron meteorite in bulk sample and in petrographic thin section. Qualitative analysis identified the elements Ca, Co, Fe, Ga, Li and Ni in the thin section and the whole meteorite. Two different methods, calibration‐free LIBS and one‐point calibration LIBS, were used as complementary methodologies for quantitative LIBS analysis. The elemental composition data obtained by LIBS were in good agreement with the compositional analyses obtained by traditional methods generally applied for the analysis of meteorites, such as ICP‐MS and EDS‐SEM. Besides the recognised advantages of LIBS over traditional techniques, including versatility, minimal destructivity, lack of waste production, low operating costs, rapidity of analysis, availability of transportable or portable systems, etc., additional advantages of this technique in the analysis of meteorites are precision and accuracy, sensitivity to low atomic number elements such as Li and the capacity to detect and quantify Co contents that cannot be obtained by EDS‐SEM.  相似文献