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1st EEGS Meeting
- Conference date: 25 Sep 1995 - 29 Sep 1995
- Location: Torino, Italy
- ISBN: 978-94-6282-129-3
- Published: 25 September 1995
1 - 50 of 142 results
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Applied Geophysics Code of Good Practice
More LessThere is a need for clients for the evaluation of geophysical servicing companies. The French companies, which untill too years ago did not possess any professional organization, have set a group to work in the direction of a better quality insurance geophysical service.
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Monitoring Creep Movements by Seismic Refraction
Authors I. Campagnoli and G. SantaratoThe Italian Apenninic area is a well known example of hydrogeological and landslide hazard, due to recent largely incoherent shallow formations like clay, sandstone, flysch. When artifacts must be built as roads, bridges, dams..., a very careful study of buried geology and lithological properties must be performed in advance, resorting to intensive geotechnical and geophysical surveys, to evaluate both geometry and mechanical properties of the shallowest formations.
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Monitoring a Landslide in Baiso by GPS Survey
Authors E. Baj and A. ColombettiThe extent to which landslides are monitored before and after the stabilisation work is limited by the high costs involved. Furthermore the more common measuring instrument, the inclinometer, is rendered useless when movement begins again and must therefore be replaced.
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Acoustic Emission and Landslide Investigation
By P. BlahaThe geoacoustic method is one of the less known geophysical methods. This method tracks natural elastic waves that are generated due to rock mass disturbances. The method is sometimes known in literature as "acoustic emissions" or the "rock noise method".
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Determination of Water Flow at the Base of a Large Landslide by Resistivity Methods
Authors A. Carbo‘Gorosabel and A. Casas PonsatiLarge Engineering works caused a 1.5 -m3- landslide on a valley slope. The material consist of coluvium: sand, silty sand overlying folded carbonifeous mudstones and sandstones. The slip plane underlies the coluvium where a clayey bed derived from the weathering of the basement favoured the landslide. The major movements are produced after raining periods. The objective is to figure out the slip plane location and the main water flow areas.
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GPR Investigations to Evaluate Geometric Features of Rock Slides and Bucklings in a Limestone Formation in Northern Italy
Authors S. E. Beaubien, F. Galadini, P. Tommasi and E. PettinelliIn recent years the application of ground penetrating radar (GPR) has been extended to a large number of geotechnical and engineering geology problems (see 5th Int. Conf on GPR, Kitchener, Canada 1995).
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VLF Measurements Applied to Landslide Investigations
Authors W. Stiefelhagen, I. Muller, H. Raetzo and O. LateltinVLF measurements are playing already some important role in the field of urineral exploration, waste deposit investigation and investigations of kanstic media. In more porous media the application of the VLF method seems to be more difficult. Nevertheless we tried to evaluate this method for the investigation of land slides in Switzerland. Surprisingly we could clearly identify some borders of the biggest recent land slide (Falli Hölli, Canton Fribourg) in Switzerland.
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Broad Band Complex Conductivity Tomography for Environmental Applications
Authors F. Borner, M. Gruhne, L. Halleux, A. Kampke, A. Weller, J. Kulenkampff and T. RichterThe properties of porous rock and soils , i.e. fluid flow permeability, sorptivity, fluid phase distribution and composition are of great interest in environmental site characterization and hydrogeological applications. Additionally, recent environmental research include the - representative determination of input parameters for groundwater and migration modelling, - noninvasive evaluation of the condition of the multiphase system subsurface - monitoring the remediation of contaminated groundwater and soil zones
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Limits of Surface Resistivity Methods in Determining Transient Parameters by Mathematical Modelling
Authors O. Mazac, I. Landa and W. E. KellyKnowledge of transient parameters (e.g., direction and velocity of groundwater or pollution flow, dispersive parameters) is necessary for analyzing pollution procesces in an aquifer. For determining the parameters, many traditional and well elaborated methods have been applied.
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Geoelectric Monitoring of a Tracer Experiment at Haslemoen, Norway, during the Winter of 1995
Authors M. Morris, O. B. Lile and J. S. RonningRecent studies have focused on the use of the geoelectrical method to monitor tracer experiments (Bevc and Morrison 1991, Karous 1993, White 1995). Geoelectrical monitoring is suggested as a replacement or as a supplement to traditional tracer experiments, which require taking actual samples of groundwater. The aim of tracer experiments is to determine hydrological parameters such as e.g. groundwater flow direction or velocity of flow.
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Detection of Contaminated Groundwater by Geoelectrical Methods
More LessHeavily contaminated groundwater usually contains quite large amount of dissolved salt. It can be expected that porous materials saturated with water of higher concentration can be characterized by lower electrical resistivity than those saturated with clean (fresh) water. Therefore different resistivity methods may be good indicators of contaminated groundwaters.
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Investigation and Simulation of Free Phase Hydrocarbon Subsurface Flaw
More LessProblems due to groundwater contamination by hydrocarbons emerged in the eighties in Hungary, similarly to the rest of the world. Contamination of subsurface water cannot be easily detected, delineation of a hydrocarbon pollution is an even more difficult task because complex problem encountered. To solve these we have to use many different methods and operations and we have to extend our scope to further disciplines and branches of science.
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Hydrocarbon Contamination around Soviet Military Bases
More LessIn the spring of 1990 the Hungarian and Soviet ministers of foreign affairs signed a protocol on the withdrawal of the Soviet troops from the territory of Hungary. According to this protocol the damage to the environment caused in almost 35 years could be assessed in 171 bases prior to the complete withdrawal. Methods of assessment were selected by a joint Hungarian-Soviet expert team.
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Electrical Effects of Pollutants in Earth Soils and Sedimentary Rocks
Authors G. Losito, M. Muschietti and A. TrovaThis work is the development of a laboratory study carried out during the last years to investigate pollution effects in sedimentary rocks. The used method is an extention of the geolelectrical method and is based on the spectral analisys of the output signals (Losito and Trova; 1981).
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Engineering Geophysics in the New German Governmental Area in the Centre of Berlin
Authors C. Gelbke, E. Raekers, B. Lehman and P. AlthausAfter reunification of Germany in 1989, the government decided that Berlin instead of Bonn will be the capital of Germany. Therefore new governmental buildings as well as underground road and railways shall be erected in the centre of Berlin until 1999. The specific area had to be surveyed with engineering geophysical and geotechnical methods. This was certainly the largest area for investigations with engineering geophysics in Germany, maybe in Europe (Fig 1 only shows half of the total surveyed area)
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Seismic Tomography in Shallow Geology
By P. BlahaTomography is a new method for processing the data obtained by radiography. Tomography has gradually found its way into the processing of geophysical measurements. The first tomographic applications were made for the processing of seismic measurements.
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Geotechnical Applications of Seismic Tomography: Case Histories
Authors E. Toros and L. HermannThe essence and the main advantage of tomographic methods are that they able to map the distribution of physical parameters inside a volume from the sequence of measurements performed on the perimeter of the domain.
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Preliminary Experiments with Radar Tomography for Civil Engineering
More LessPreliminary tests on laboratory models enable us to provide guidelines for traveltime ray tomography with G.P.R. applied to civil engineering problems, specifically to find voids in pillars, walls and structures. The width of the Fresnel zone and the source and receiver locations are the limits to resolution capabilities. For crosshole geometry a criterion to know resolution capabilities, based on detectable wavenumbers, is analytically derived.
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On Site Sonic Tomography Data Processing and Analysis for Dam Investigations
Authors P. Angeloni, G. Bettolo, S. Superbo and A. ZaninettiIn Italy, sonic methods (using elastic waves in the sonic frequency range) for monitoring dams have been in use for about 30 years, in the framework of ENEL's project regarding the systematic monitoring and restoring of old dams. The investigated dams are made of both reinforced concrete and masonry.
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Environmental and Structural Dynamic Monitoring Using High Dynamic Seismic Acquisition Systems
Authors P. Angeloni, G. Gardini, M. Mucciarelli and A. ZaninettiThe need for a wider and even more efficient monitoring for the safety of important civil works like dams has been a key element for stimulating the development and evolution of investigation methodologies and more and more sophisticated monitoring systems.
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The Application of Shear-Wave Reflection Seismics in Shallow Subsurface Investigations
Authors J. Brouwer, V. Nijhof and F. LuitenIn the past decades we have seen the introduction of shallow reflection seismic investigation techniques for application in engineering projects. Although some papers report the use of Shearwave techniques for engineering purposes (e.g. Suyama et al, 1987), the P-wave method has obviously been more attractive. P-wave seismics, however, suffer from a number of fundamental problems that cannot easily be solved: • the P-wave method only indirectly (through AVO) addresses the shear-strength of the soils whereas this parameter is usually of major interest in engineering projects; • within the depth-range of interest (< 50 m) the P-wave method is relatively insensitive to changes in lithology that are significant from an engineering point of view; • within the depth range of interest the P-wave data can be 'blurred' by weathering layer effects (multiples, attenuation, etc.) thus limiting recognition and interpretation of deeper information.
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Shear Wave Velocities of Campanian Tuffs (Southern Italy)
Authors F. M. Guadagno, R. Mele and C. NunziataShear wave velocities of Campanian tuffs were measured both in the laboratory (ultrasonic pulse and resonant column) and in the field (Rayleigh wave spectral analysis). It resulted that it is not sufficient to recognize the tuff basement for computing the site amplification effects, but the dynamic parameters have to be measured because of hardening variation and fracturing.
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Transient Electromagnetic Soundings Applied to Hydrogeology: Some Case Histories in Central Italy
Authors S. Floris, A. Menghini and G. PaganoThese short notes report the results we collected for over four years in geophysical investigations, applied to hydrogeology on various geologic situations in Central Italy, by timedomain electromagnetic method (TDEM). Detailed stratigraphic knowledges, by drillings, allowed a direct comparison with geophysical data.
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High Resolution Seismic Imaging of a Shallow Aquifer
Authors Z. Hajnal, C. D. Hooge and B. SchreinerTwo intersecting high resolution surveys, designed with the support of advanced modelling results, mapped shallow ground-water aquifers. The project was intended to determine optimal data acquisition and processing parameters to image fluids in shallow glacial till deposits. The survey not only imaged the expected target but recognized previously unknown stratigraphic variations within the aquifer. In addition, a study built on geophysical information was initiated to enhance a better understanding of the mechanical properties of till deposits. The test site for the investigation is located north of Saskatoon, Saskatchewan, Canada (Figure 1).
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Applicability of Shallow Cross-Well Tomography in Ground Water Investigations
Authors M. van Kempen, K. Roy-Chowdhurry and W. SpakmanGround water flow is known to be affected by presence of thin, impermeable clay layers. In an area near Ede in Holland, reflection seismics could not be used to detect continuity of such clay layers, due to the presence of a low velocity lid. The applicability of cross-well tomography to this situation was then investigated.
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TDEM Soundings for Locating Aquifers inside the Caldeira of Fogo Active Volcano, Cape Verde Islands
Authors M. Descloitres, M. Ritz and P. MourguesFogo is the highest island of the archipelago of Cape Verde situated 500 km west from Senegal (West Africa). It is an active volcano with a diameter of 27 km and geological outline can be describe as follow: in the beginring, a predominantly effusive vólcanic activity has formed the lower cone overlying a carbonatitic basement.
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Dilution Technique in the Logging Variant: State of the Art
More LessIn an aquifer with confined as well as unconfined groundwater level, the movement of groundwater is usually observed in the direction of the hydraulic gradient. This movement can be described quantitatively by a vector of the filtration velocity Vf with a prevailing horizontal or subhorizontal component, which can be determined reliably in a well penetrating the aquifer.
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Contribution of Geophysical Well-Logging Techniques to Evaluation of Water Resources
More LessCarrying out borehole geophysics measurements applicable to ground-water studies repeatedly in time we can monitore both the dynamics regime of underground water and technical parameters of the borehole. Geophysical logs can be reinterpreted in a post mortem investigation of some geologic or hydrologic factor that was not considered while the hole was being drilled.
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Fluid Logging: the Dilution Technique
Authors D. Chapellier, V. D. Le, A. Re, V. Iliceto and S. MaresRecourse to timed borehole fluid logging after tracer tests (dilution technique) makes it possible to determine, in a mathematical manner, the flow rate and filtration speed up to values of 10-5 m/sec in the case of an induced or natural flow. It also makes possible the continuous recording of variations in these parameters according to the depth. With the help of a tracer, usually NaCI, the variation over time of the electrolytic borehole fluid is studied.
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Maximum Likelihood Object Location Employing Magnetometer and Radar Surface Data
Authors I. Johansen and L. J. GeliusEnvironmental projects concerning site characterization or remediation may also include the problem of locating known objects such as buried drums, unexploaded ordnances, etc.
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Prediction of Rock Temperatures and Water lnflow Zones in Deep Tunnels
Authors A. Busslinger and L. RybachIn deep tunnelling/mining the knowledge of in-site rock temperatures is of paramount importance, e.g. for planning of the underground operabons or for the design of ventilation. During construction large water inflows from karstic or fracture zones can lead to disastrous geotechnical problems. In the following, examples will be presented to predict rock temperatures and water inflow zones.
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Geophysical Imagery of Small-Scale Fracturing
Authors J. C. Gourry and G. GrandjeanInsufficient knowledge of fractured rock represents a common problem in many fields of the Earth Sciences such as the environment, storage, hydrogeology, etc. The study presented here was undertaken in ornamental stone quarries, which offers the main advantage of being able to verify geophysical interpretation after cutting of the working face (meso-scale) or the blocks (micro-scale). As far as the meso-scale is concerned, the aim is to make an inventory of fracturen of an order of approximately 1 m in length, whereas for the micro-scale, it is to identify fractures of up to ten centimetres.
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Advanced GPR Exploration in Karstic Areas
Authors I. Finetti, M. Pipan and G. CandottiMultifold GPR techniques and 3D common offset GPR grids were used for a high resolution geophysical exploration programme in the karstic area surrounding the town of Trieste (Italy). The objective of the programme is the identification of natural cavities and fractures, of interest for applications rangmg from quarry exploitation to civil engineering.
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Use of Geophysical Methods in Old Coal Mine Site Investigations: Some Case Studies
Authors S. C. J. Dawson, K. R. Onions and P. J. JacksonSince the early 1980's, the UK coat industry has declined in size from 200 to its current level of 20 major collieries. Whilst this has meant a reducing demand for Goal exploration geophysics, a new market is emerging: that of site investigations prior to the reclamation of abandoned colliery sites.
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Borehole Radar Survey Applied to a HST Tunnel Investigation
Authors L. Corin, L. Halleux, B. Dethy and T. RichterConsidering the high cost of boreholes, any technique providing additional information on the rockmass around the borehole is extremely useful. Geotechnical tests and geophysical logging techniques are widely used, but the information they provide is only representative of the immediate vicinity of the borehole.
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Earth Resistivity Tomography (ERT) and Cavity Investigation
By F. JacobsTomographic inversion methods appeared in geophysics about ten years ago. In general, they are based upon the principle of transmission of geological bodies by means of elastic or electromagnetic waves, especially in seismology and in engineering geophysics.
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Comparison Between some Borghole Geophysical Methods to Defect Underground Cavities
Authors R. Lagabrielle, P. Cote and N. Lecocq-LeventWhen underground cavities have geometrical characteristics (size and depth) or feature geophysical contrasts which place them beyond the detection limits of surface geophysical methods, borehole geophysics should be used to make sure that they can be detected if they actually exist.
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Single Geophone Profiling (SGRP) Used in the Detection of Lateral Vetocity Changes: Example of Cavity Detection
Authors R. Gauderon, G. Alleman and D. ChapellierThe interest of this new type of research consists in setting up a new method based on the common seismic refraction and reflection methods which are sometimes too expensive and too complex to use. These reasons have led us to develop a new method, the Single Geophone Refraction Profiling (SGRP), which makes possible the rapid and inexpensive interpretation of a chosen site.
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Airborne Geophysics for Geotechnical Applications (Tunnel Location)
Authors W. Seiberl, R. Arndt, A. Romer, R. Supper and G. OberlercherThis papers focusses on the results gained from a hydrogeological study and their geotechnical implications for a tunneling project to be planned in the Inn-Valley (Tyrol).
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Processing of Very High Resolution 3D Marine Seismic Data
Authors T. Missiaen, B. Marsset, M. Noble and W. VersteegVery High Resolution marine 3D seismics offers wide use both in the field of engineering geophysics as well as for geological and environmental site investigations. Considering the frequency content of the data, specific 3D processing techniques have to be applied in order to obtain a correct image of the subsurface. Due to the average wavelength of the "seismic signal and the width of its associated Fresnel zone, CMP-like processing can still lead to a destructive stack of misplaced events. The latter will also be the case if precise time delay corrections are not applied. A first step in the development of such 3D processing techniques was done using a very high resolution 3D data volume previously acquired on the river Schelde in Antwerpen.
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High Resolution, Microseismic Profiling in the Coastal Zone
By A. StefanonThe latest techniques and instrumentation allow to perform successful reflection seismic surveys both at sea and in inland waters, even at very shallow water depth and using small crafts. Such talk is not easily achieved, but the obtainable results are definitely rewarding and pay welf botte for the indispensable effort and for the money involved.
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Geophysical Remote Sensing of Sea Floor Sediment Properties
Authors A. M. Davis and M. D. RichardsonIn the marine environment, geophysical methods have for many years been used to investigate subsurface structure and to map the distribution of sediments at the seabed surface, the latter using a purely qualitative approach.
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Sea Floor Sensing of Sediment Shear Wave Properties
More LessKnowledge of sediment geoacoustic properties is of fundamental importance to marine environmental end engineering applications. For instance, geoacoustic approaches are currently being applied to predictions of marine slope stability, evaluation of the consolidation behaviour and strength of marine foundations, studies of mine burial, assessment of contaminant distribution, and prediction of high frequency acoustic bottom scattering. Within the engineering community the geophysical parameter currently receiving most attention is the seismic shear wave velocity, this being recognised as a definitive soil property indicative of the structural stiffness of the material. Out of this has arisen a requirement for new methods for in-situ evaluation.
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Preliminary Results of Seismic and GPR Surveys on the Hells Gate lce Shelf (Victoria Land -Antarctica)
Authors A. Lozej, I. Tabacco, F. Merlanti and M. PavanIn the course of the ItaliAntartide Expedition of the summer 1993-1995, geophysical surveys, seismic and GPR, were undertaken on the Hells Gate Ice Shelf with the objective of defining the structural and physical characteristics of the ice body. The Hells Gate Ice Shelf (HGIS) is one of the minor glacial structures in the North Victoria Land area, the geomorphology and glaciology of which are described by Baroni & Orombelli (1987) and Baroni (1990), among others.
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Radar and Seismic Survey on Temperate Glaciers in Northern Italy, Adamello and Stelvio Glacier
Authors I. Tabacco, P. Pettinicchio and L. VeroneseRadar survey on temperate glaciers is more difficult on respect of the other one on polar, Gold glaciers, because the presence of a scattered layers that usually prevent the transmission of e.m. waves. Bogodorosky (1985) consider that the scattered layer is due to in fraglacial discontinuity and to physical caratheristics of the ice body.
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Investigation of Fine Structures of Buried River Beds
Authors B. Neducza and M. PattantyusThe objective of investigations for buried river beds and alluvial fans might primarily be water or raw material prospecting but it might be of archaeological importance, too. Ancient settlements can frequently be found close to a water supply, e.g. a river, thus, delineation of river beds could help in finding ancient or historical settlements. Analyzis of aerial photographs and topographic maps of proper scale is the best means for this purpose.
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High-Resolution Seismic Mapping of Glacial and Proglacial Sediments in the Swiss Molasse Basin
Authors F. Buker, A. Pugin, H. Horstmeyer and A. GreenQuarternary sediments in the Swiss Molasse Basin contain more than two-thirds of the country's aquifers and large amounts of industrial minerals. Glacial sediments are highly inhomogenous, such that their lithology and hydraulic conductivity may change significantly over short distances. As groundwater flow is influenced strongly by hydraulic conductivity, evaluations of the safety of waste disposal sites and predictions about hazardous contaminant flow require reliable information about the three-dimensional distribution of the near-surface sediments that are highly permeable.
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Geophysical Investigation on Geometry and Internal Structure of the Lago Sackung, Calabria
Authors F. Ferrucci, M. Sorriso-Valvo and C. TansiQuantitative studies of deep-seated gravitational dope deformations, that often represent the longlasting preparatory phase of catastrophic landslides, though seldom carried out are undoubtedly relevant to hazard assessment and to the correct planning of environmental frameworking.
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