Seismic-induced rockfalls and landslide dam following the October 30, 2016 earthquake in Central Italy     

Saverio Romeo  Lucio Di Matteo  Laura Melelli  Corrado Cencetti  Walter Dragoni  Andrea Fredduzzi 《Landslides》2017,14(4):1457-1465

On October 30, 2016, a seismic event and its aftershocks produced diffuse landslides along the SP 209 road in the Nera River Gorge (Central Italy). Due to the steep slopes and the outcropping of highly fractured and bedded limestone, several rockfalls were triggered, of which the main event occurred on the slope of Mount Sasso Pizzuto. The seismic shock acted on a rock wedge that, after an initial slide, developed into a rockfall. The debris accumulation blocked the SP 209 road and dammed the Nera River, forming a small lake. The river discharge was around 3.6 m³/s; the water overtopped the dam and flooded the road. By a preliminary topographic survey, we estimated that the debris accumulation covers an area of about 16,500 m², while the volume is around 70,000 m³. The maximum volume occupied by the pre-existing talus mobilized by the rockfall is about 20% of the total volume. Besides blocking the road, the rockfall damaged a bridge severely, while, downstream of the dam, the water flow caused erosion of a road embankment. A rockfall protection gallery, a few hundred meters downstream of the dam, was damaged during the event. Other elastic nets and rigid barriers were not sufficient to protect the road from single-block rockfalls, with volumes around 1–2 m³. Considering the geological and geomorphological conditions, as well as the high seismicity and the socioeconomic importance of the area, a review of the entire rockfall protection systems is required to ensure protection of critical infrastructure and local communities.  相似文献   

Dynamics of the circulation in the Sea of Marmara: numerical modeling experiments and observations from the Turkish straits system experiment   总被引：4，自引：3，他引：1  

Jacopo?ChiggiatoEmail author  Ewa?Jarosz  Jeffrey?W.?Book  James?Dykes  Lucio?Torrisi  Pierre-Marie?Poulain  Riccardo?Gerin  Jochen?Horstmann  ?ükrü?Be?iktepe 《Ocean Dynamics》2012,62(1):139-159

During September 2008 and February 2009, the NR/V Alliance extensively sampled the waters of the Sea of Marmara within the framework of the Turkish Straits System (TSS) experiment coordinated by the NATO Undersea Research Centre. The observational effort provided an opportunity to set up realistic numerical experiments for modeling the observed variability of the Marmara Sea upper layer circulation at mesoscale resolution over the entire basin during the trial period, complementing relevant features and forcing factors revealed by numerical model results with information acquired from in situ and remote sensing datasets. Numerical model solutions from realistic runs using the Regional Ocean Modeling System (ROMS) produce a general circulation in the Sea of Marmara that is consistent with previous knowledge of the circulation drawn from past hydrographic measurements, with a westward meandering current associated with a recurrent large anticyclone. Additional idealized numerical experiments illuminate the role various dynamics play in determining the Sea of Marmara circulation and pycnocline structure. Both the wind curl and the strait flows are found to strongly influence the strength and location of the main mesoscale features. Large displacements of the pycnocline depth were observed during the sea trials. These displacements can be interpreted as storm-driven upwelling/downwelling dynamics associated with northeasterly winds; however, lateral advection associated with flow from the Straits also played a role in some displacements.  相似文献   

Soil–pile–structure interaction: experimental outcomes from shaking table tests          下载免费PDF全文

Maria Giovanna Durante  Luigi Di Sarno  George Mylonakis  Colin A. Taylor  Armando Lucio Simonelli 《地震工程与结构动力学》2016,45(7):1041-1061

An effective way to study the complex seismic soil‐structure interaction phenomena is to investigate the response of physical scaled models in 1‐g or n‐g laboratory devices. The outcomes of an extensive experimental campaign carried out on scaled models by means of the shaking table of the Bristol Laboratory for Advanced Dynamics Engineering, University of Bristol, UK, are discussed in the present paper. The experimental model comprises an oscillator connected to a single or a group of piles embedded in a bi‐layer deposit. Different pile head conditions, that is free head and fixed head, several dynamic properties of the structure, including different masses at the top of the single degree of freedom system, excited by various input motions, e.g. white noise, sinedwells and natural earthquake strong motions recorded in Italy, have been tested. In the present work, the modal dynamic response of the soil–pile–structure system is assessed in terms of period elongation and system damping ratio. Furthermore, the effects of oscillator mass and pile head conditions on soil–pile response have been highlighted, when the harmonic input motions are considered. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Residual Exchange Flows in Subtropical Estuaries   总被引：1，自引：0，他引：1  

Arnoldo Valle-Levinson  Guillermo Gutierrez de Velasco  Armando Trasviña  Alejandro J. Souza  Reginaldo Durazo  Ashish J. Mehta 《Estuaries and Coasts》2009,32(1):54-67

Observations of residual exchange flows at the entrance to four subtropical estuaries, two of them semiarid, indicate that these flows are mainly tidally driven, as they compare favorably with theoretical patterns of tidal residual flows. In every estuary examined, the tidal behavior was that of a standing or near-standing wave, i.e., tidal elevation and tidal currents were nearly in quadrature. The pattern of exchange flow that persisted at every estuary exhibited inflow in the channel and outflow over the shoals. Curiously, but also fortuitously, this pattern coincides with the exchange pattern driven by density gradients in other estuaries. The tidal stresses and the residual elevation slopes should be the dominant mechanisms that drive such tidal residual pattern because the Stokes transport mechanism is negligible for standing or near-standing waves. Time series measurements from the semiarid estuaries showed fortnightly modulation of the residual flow by tidal forcing in such a way that the strongest net exchange flows developed with the largest tidal distortions, i.e., during spring tides. This modulation is opposite to the modulation that typically results in temperate estuaries, where the strongest net exchange flows tend to develop during neap tides. The fortnightly modulation on tidal residual currents could be inferred from previous theoretical results because residual currents arise from tidal distortions but is made explicit in this study. The findings advanced herein should allow the drawing of generalities about exchange flow patterns in subtropical estuaries where residual flows are mainly driven by tides.  相似文献   

Vegetation and topographic controls on sediment deposition and storage on gully beds in a degraded mountain area   总被引：1，自引：0，他引：1  

Armando Molina  Gerard Govers  Felipe Cisneros  Veerle Vanacker 《地球表面变化过程与地形》2009,34(6):755-767

Active gully systems developed on highly weathered or loose parent material are an important source of runoff and sediment production in degraded areas. However, a decrease of land pressure may lead to a return of a partial vegetation cover, whereby gully beds are preferred recolonization spots. Although the current knowledge on the role of vegetation on reducing sediment production on slopes is well developed, few studies exist on the significance of restoring sediment transport pathways on the total sediment budget of degraded mountainous catchments. This study in the Ecuadorian Andes evaluates the potential of vegetation to stabilize active gully systems by trapping and retaining eroded sediment in the gully bed, and analyses the significance of vegetation restoration in the gully bed in reducing sediment export from degraded catchments. Field measurements on 138 gully segments located in 13 ephemeral steep gullies with different ground vegetation cover indicate that gully bed vegetation is the most important factor in promoting short‐term (1–15 years) sediment deposition and gully stabilization. In well‐vegetated gully systems ( ≥ 30% of ground vegetation cover), 0.035 m³ m^–1 of sediment is deposited yearly in the gully bed. Almost 50 per cent of the observed variance in sediment deposition volumes can be explained by the mean ground vegetation cover of the gully bed. The presence of vegetation in gully beds gives rise to the formation of vegetated buffer zones, which enhance short‐term sediment trapping even in active gully systems in mountainous environments. Vegetation buffer zones are shown to modify the connectivity of sediment fluxes, as they reduce the transport efficiency of gully systems. First calculations on data on sediment deposition patterns in our study area show that gully bed deposition in response to gully bed revegetation can represent more than 25 per cent of the volume of sediment generated within the catchment. Our findings indicate that relatively small changes in landscape connectivity have the potential to create strong (positive) feedback loops between erosion and vegetation dynamics. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Dispersivity Estimates from a Tracer Experiment in a Sandy Aquifer     

Dirk Mallants  Armando Espino  Marijke Van  Hoorick  Jan Feyen  Noel Vandenberghe  Walter Loy 《Ground water》2000,38(2):304-310

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Landfill development in the urban fringe of Metro Manila     

Yuji Hara  Kazuhiko Takeuchi  Armando M. Palijon  Akinobu Murakami 《GeoJournal》2008,71(2-3):127-141

In low-lying areas of urban and suburban regions in Asia, the use of landfill has allowed urban land use to encroach onto watery landforms, such as back marshes, which were formerly used as rice fields. To improve understanding of the associations between land-use patterns and landfill development, we carried out a case study in the urban fringe of Metro Manila in the Philippines. We examined landfill volume derived from land-use change using GIS, and field surveyed qualitative aspects of the landfill used. We calculated the rate of application of landfill in low-lying housing development areas to be 5.0 × 10³ m³ km^?2 year^?1, most of which consisted of offsite disposal of construction waste or crushed rock produced by urban development and renewal on the adjoining uplands. The flow of fill material from offsite sources to onsite landfill development areas was on the basis of individual agreements between suppliers and developers.  相似文献   

The structure of the Campanian Plain and the activity of the Neapolitan volcanoes (Italy)     

Roberto Scandone  Francesca Bellucci  Lucio Lirer  Giuseppe Rolandi 《Journal of Volcanology and Geothermal Research》1991,48(1-2)

The central Campanian Plain is dominated by the structural depression of Acerra whose origin is tectonic, but may have been enlarged and further depressed after the eruption of the Campanian Ignimbrite (42-25 ka). The deposits of the Campanian Ignimbrite are possibly the results of multiple eruptions with huge pyroclastic deposits that covered all the Campanian Plain.The more recent activity of Vesuvius, Campi Flegrei and Procida occurred on the borders of Acerra depression and resulted from a reactivation of regional faults after the Campanian Ignimbrite cycle. The activity of Vesuvius produced the building of a stratovolcano mostly by effusive and plinian explosive eruptions. The Campi Flegrei area, on the contrary, was dominated by the eruption of the Neapolitan Yellow Tuff at 12 ka that produced a caldera collapse of the Gulf of Pozzuoli. The caldera formation controlled the emplacement of the recent activity of Campi Flegrei and the new volcanoes were formed only within the caldera or along its rim.  相似文献   

Eruption and mass-wasting-induced processes during the late holocene destructive phase of Nevado del Ruiz volcano, Colombia     

Jean-Claude Thouret  Rosalba Salinas  Armando Murcia 《Journal of Volcanology and Geothermal Research》1990,41(1-4)

The November 13, 1985, eruption was characteristic of the Arenas eruptive stage of Nevado del Ruiz, the most recent of a series of twelve eruptive stages that have occurred in the past 11,000 years. Eruptive sequences, deposits and processes similar to that of 1985 have characterized the behavior of Nevado del Ruiz during three major prehistorical and historical eruptive stages: the approximately 3300-3100 yr. B.P. Hedionda, the 16th century Azufrado, and the mid-1800's Lagunillas eruptive stages, that partly destroyed the present Ruiz summit.According to the interpretation of the stratigraphic record of prehistorical eruptions and historical accounts, almost every recent magmatic event was small or short-lived. Nevertheless, rockslide-debris avalanches and catastrophic debris flows were triggered in all the eruptions owing to slope failures related to specific tectonic features of Ruiz volcano and/or to significant interactions between pyroclastic debris and the ice cap. Evidence for headward retreat of avalanche scarps during multiple eruptions reinforce the case that large slope failures can occur repeatedly at a large-volume volcano like Ruiz without reconstruction of the edifice. The latest Ruiz eruptions that involved rockslide-debris avalanches resemble in part the Shiveluch 1964 event for which evidence of lateral blast deposits are lacking, but differ in part from this type because non-eruptive and mass-wasting processes also triggered rockslide-debris avalanches.Many factors render the cluster of domes of the Ruiz summit unstable, including: (1) deeply dissected troughs opened toward the north-northeast (Azufrado), east (Lagunillas), and south (Recio) flanks; (2) strongly hydrothermally altered north and east flanks of the summit; (3) currently glaciated or recently deglaciated, high cliffs; (4) steep unstable margins of the ice cap on the north and east.Thus, in light of its past behavior, a small eruption or an earthquake might trigger catastrophic rockslide-debris avalanches. Furthermore, such avalanches as well as glacial outburst-floods and ice avalanches could induce debris flows by mobilizing weathered, water-saturated, and unconsolidated rocks or deposits.  相似文献   

Wind-Speed Profile and Roughness Sublayer Depth Modelling in Urban Boundary Layers     

Armando Pelliccioni  Paolo Monti  Giovanni Leuzzi 《Boundary-Layer Meteorology》2016,160(2):225-248

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