bluuebunny/crossref_metadata_2025 huggingface dataset:
Landslide susceptibility assessment of SE Bartin (West Black Sea region, Turkey) by artificial neural networks
Authors: Ercanoglu M.
Published: April 2010

Abstract. Landslides are significant natural hazards in Turkey, second only to earthquakes with respect to economic losses and casualties. The West Black Sea region of Turkey is known as one of the most landslide-prone regions in the country. The work presented in this paper is aimed at evaluating landslide susceptibility in a selected area in the West Black Sea region using Artificial Neural Network (ANN) method. A total of 317 landslides were identified and mapped in the area by extensive field work and by use of air photo interpretations to build a landslide inventory map. A landslide database was then derived automatically from the landslide inventory map. To evaluate landslide susceptibility, six input parameters (slope angle, slope aspect, topographical elevation, topographical shape, wetness index, and vegetation index) were used. To obtain maps of these parameters, Digital Elevation Model (DEM) and ASTER satellite imagery of the study area were used. At the first stage, all data were normalized in [0, 1] interval, and parameter effects on landslide occurrence were expressed using Statistical Index values (Wi). Then, landslide susceptibility analyses were performed using an ANN. Finally, performance of the resulting map and the applied methodology is discussed relative to performance indicators, such as predicted areal extent of landslides and the strength of relation (rij) value. Much of the areal extents of the landslides (87.2%) were classified as susceptible to landsliding, and rij value of 0.85 showed a high degree of similarity. In addition to these, at the final stage, an independent validation strategy was followed by dividing the landslide data set into two parts and 82.5% of the validation data set was found to be correctly classified as landslide susceptible areas. According to these results, it is concluded that the map produced by the ANN is reliable and methodology applied in the study produced high performance, and satisfactory results.
Evidence of slope instability in the Southwestern Adriatic Margin
Authors: Minisini D. , Trincardi F. , Asioli A.
Published: April 2010

Abstract. The Southwestern Adriatic Margin (SAM) shows evidence of widespread failure events that generated slide scars up to 10 km wide and extensive slide deposits with run out distances greater than 50 km. Chirp-sonar profiles, side-scan sonar mosaics, multibeam bathymetry and sediment cores document that the entire slope area underwent repeated failures along a stretch of 150 km and that mass-transport deposits, covering an area of 3320 km2, are highly variable ranging from blocky slides to turbidites, and lay on the lower slope and in the basin. The SAM slope between 300–700 m is impacted by southward bottom currents shaping sediment drifts (partly affected by failure) and areas of dominant erosion of the seafloor. When slide deposits occur in areas swept by bottom currents their fresh appearence and their location at seafloor may give the misleading impression of a very young age. Seismic-stratigraphic correlation of these deposits to the basin floor, however, allow a more reliable age estimate through sediment coring of the post-slide unit. Multiple buried failed masses overlap each other in the lower slope and below the basin floor; the most widespread of these mass-transport deposits occurred during the MIS 2-glacial interval on a combined area of 2670 km2. Displacements affecting Holocene deposits suggest recent failure events during or after the last phases of the last post-glacial eustatic rise. Differences in sediment accumulation rates at the base or within the sediment drifts and presence of downlap surfaces along the slope and further in the basin may provide one or multiple potential weak layers above which widespread collapses take place. Neotectonic activity and seismicity, together with the presence of a steep slope, represent additional elements conducive to sediment instability and failure along the SAM. Evidence of large areas still prone to failure provides elements of tsunamogenic hazard.
New information on earthquake history of the Aksehir-Afyon Graben System, Turkey, since the second half of 18th century
Authors: Ozer N.
Published: April 2010

Abstract. Researches aimed at enriching the number of available documentary sources on earthquakes have an important role in seismology. To this end, this paper documents the history of prominent earthquakes associated with the NW-SE trending Sultandag-Aksehir Fault and Aksehir-Afyon graben system in Western-Central Anatolia since the historical times through 1766. This work also combines the earthquake data for both historical and instrumental periods, previously listed in various catalogues and resources, for the studied area. Documents from the Ottoman archives and libraries as well as the Ottoman and Turkish newspapers were scrutinized, and eight previously unreported earthquakes in the latter half of the nineteenth century and four new earthquakes in the period 1900–1931 were revealed. For the period from 1766 to 1931, the total number of known earthquakes for the area under investigation increased from eighteen to thirty thanks to the document search. Furthermore, the existing information on eleven previously reported earthquakes is updated for the period from 1862 to 1946. Earthquakes from 1946 to 1964 are compiled from the catalogues for data completeness.
A revision of the 1783–1784 Calabrian (southern Italy) tsunamis
Authors: Graziani L. , Maramai A. , Tinti S.
Published: April 2010

Abstract. Southern Italy is one of the most tsunamigenic areas in the Mediterranean basin, having experienced during centuries a large number of tsunamis, some of which very destructive. In particular, the most exposed zone here is the Messina Straits separating the coasts of Calabria and Sicily that was the theatre of the strongest Italian events. In 1783–1785 Calabria was shaken by the most violent and persistent seismic crisis occurred in the last 2000 years. Five very strong earthquakes, followed by tsunamis, occurred in a short interval of time (February–March 1783), causing destruction and a lot of victims in a vast region embracing the whole southern Calabria and the Messina area, Sicily. In this study we re-examined these events by taking into account all available historical sources. In particular, we focussed on the 5 and 6 February 1783 tsunamis, that were the most destructive. As regards the 5 February event, we found that it was underestimated and erroneously considered a minor event. On the contrary, the analysis of the sources revealed that in some localities the tsunami effects were quite strong. The 6 February tsunami, the strongest one of the sequence, was due to a huge earthquake-induced rockfall and killed more than 1500 people in the Calabrian village of Scilla. For this event the inundated area and the runup values distribution were estimated. Further, the analysis of the historical sources allowed us to find three new tsunamis that passed previously unnoticed and that occurred during this seismic period. The first one occurred a few hours before the large earthquake of 5 February 1783. The second was generated by a rockfall on 24 March 1783. Finally, the third occurred on 9 January 1784, probably due to a submarine earthquake.
Mathematical modelling of the landslide occurred at Gagliano Castelferrato (Italy)
Authors: Maugeri M. , Motta E. , Raciti E.
Published: April 2010

Abstract. Shallow slopes in clayey colluvial covers are often involved in progressive downhill motion with discontinuous rate of movements, depending on fluctuations in pore-water pressure. In geotechnical engineering research on natural slopes, the main efforts have been concentrated on stability analysis, always with a rigid perfectly plastic body assumption. In case of slow slope movements, however, the notion of stability losses its sense, so the main question is not to evaluate a stability factor, but to model a velocity field and to define the kinematic and dynamic features of the movement (mobility analysis). Many authors, in their researches, deal with slow slope movements and for the complexity of the problem and the great number of parameters involved they agree about applying numerical techniques (FEM, FDM) and advanced material modelling (elastoviscoplasticity) and suggest to calibrate the involved parameters values with the help of ''back analyses'' of existing case histories. In this paper a mathematical model predicting the landslide body viscous deformations, is presented. The model has been implemented in a computer FDM code, and has been tested on some well known case histories. Here it is applied to the case of a landslide occurred at Gagliano Castelferrato (Sicily – Italy), where a great number of field measurements was available.
Unified approach to catastrophic events: from the normal state to geological or biological shock in terms of spectral fractal and nonlinear analysis
Authors: Eftaxias K. A. , Kapiris P. G. , Balasis G. T. , Peratzakis A. , Karamanos K. , Kopanas J. , Antonopoulos G. , Nomicos K. D.
Published: April 2010

Abstract. An important question in geophysics is whether earthquakes (EQs) can be anticipated prior to their occurrence. Pre-seismic electromagnetic (EM) emissions provide a promising window through which the dynamics of EQ preparation can be investigated. However, the existence of precursory features in pre-seismic EM emissions is still debatable: in principle, it is difficult to prove associations between events separated in time, such as EQs and their EM precursors. The scope of this paper is the investigation of the pre-seismic EM activity in terms of complexity. A basic reason for our interest in complexity is the striking similarity in behavior close to irreversible phase transitions among systems that are otherwise quite different in nature. Interestingly, theoretical studies (Hopfield, 1994; Herz and Hopfield 1995; Rundle et al., 1995; Corral et al., 1997) suggest that the EQ dynamics at the final stage and neural seizure dynamics should have many similar features and can be analyzed within similar mathematical frameworks. Motivated by this hypothesis, we evaluate the capability of linear and non-linear techniques to extract common features from brain electrical activities and pre-seismic EM emissions predictive of epileptic seizures and EQs respectively. The results suggest that a unified theory may exist for the ways in which firing neurons and opening cracks organize themselves to produce a large crisis, while the preparation of an epileptic shock or a large EQ can be studied in terms of ''Intermittent Criticality''.
Assessing the efficiency and the criticality of the elements belonging to a complex territorial system subject to natural hazards
Authors: Minciardi R. , Sacile R. , Trasforini E.
Published: April 2010

Abstract. The effects of natural hazards can be mitigated by the use of proper "pre-event" interventions on "key" elements of the territory, that is on elements that are mostly vulnerable to a given catastrophic scenario and whose loss of functionality can cause damages on people, property and environment. In this respect, methodologies and tools should be studied to support decision makers in the analysis of a territory, in order to point out such elements. In this work, vulnerability is taken into account under two aspects: "physical vulnerability", which measures the propensity of a territorial element to suffer damage when subject to an external stress corresponding to the occurrence of a natural phenomenon; "functional vulnerability", which measures the propensity of a territorial element to suffer loss in functionality, even when that is caused by the loss of functionality of other territorial elements. In the proposed modeling approach, vulnerability is represented through the use of a graph-based formalization. A territorial system is represented as a complex set of elements or sub-systems. Such elements have differentiated and dedicated functions, and they may be functionally interconnected among them. In addition, vulnerability is defined through the use of two different variables, namely the criticality and the efficiency. Focusing the attention on the temporal phases corresponding to the occurrence of a calamitous event, the first one measures the service demand of an element, whereas the efficiency is a measure of the service that can be offered by such an element. The approach presented is largely independent from the natural risk considered. Besides, the tools introduced for the vulnerability analysis of the territorial system can also be used to formalize decision problems relevant to the location of the available resources for emergency management. A specific case study pertaining to the hydrological risk in the Val di Vara area (Italy) is presented.
The cases of June 2000, November 2002 and September 2002 as examples of Mediterranean floods
Authors: Milelli M. , Llasat M. C. , Ducrocq V.
Published: April 2010

Abstract. Four flood events that affected three different countries are here described in terms of meteorological genesis and in terms of consequences on the population and on the territory. Each event is a good representative of a class of phenomena that produce important effects on the urban and extra-urban tissue and that must be taken into account in an optic of civil protection and risk evaluation. This is the subject of the HYDROPTIMET project, part of the Interreg IIIB program, which is collocated in the framework of the prevention of natural hazards and, in particular, those related to severe meteo-hydrological events. This paper aims at being a general introduction of the four events which are the subject of more detailed studies, already published or under submission.
A conceptual approach to the use of Cost Benefit and Multi Criteria Analysis in natural hazard management
Authors: Gamper C. D. , Thöni M. , Weck-Hannemann H.
Published: April 2010

Abstract. Decision-making for protection measures against natural hazards entails major complexities for final decision makers. The issue in question does not only implicate a variety of criteria that need to be considered but also scarce financial resources make the allocation decision a difficult task. Furthermore, these decisions appear to be multidisciplinary in nature. Stakeholders from experts over politicians and the public are among the affected parties in making and dealing with the consequences of such decisions. In order to capture the complexity that arises when incorporating the varieties of interests as well as impacts protection measures have on the environment, the economy and society, transparent and multidisciplinary decision support techniques are needed. This paper looks at how Cost Benefit Analysis (CBA), a tool already applied to decisions concerning protective measures, and Multi Criteria Analysis (MCA), even though new to the field as such but already successfully practiced in other environmental areas, perform according to the abovementioned criteria. A conceptual overview of the methodologies will be given along with a discussion of the respective strengths and weaknesses. Looking at past applications, this overview gives an analysis about the potential of socio economics in its contribution to natural hazard research.
Statistical analysis and modelling of weather radar beam propagation conditions in the Po Valley (Italy)
Authors: Fornasiero A. , Alberoni P. P. , Bech J.
Published: April 2010

Abstract. Ground clutter caused by anomalous propagation (anaprop) can affect seriously radar rain rate estimates, particularly in fully automatic radar processing systems, and, if not filtered, can produce frequent false alarms. A statistical study of anomalous propagation detected from two operational C-band radars in the northern Italian region of Emilia Romagna is discussed, paying particular attention to its diurnal and seasonal variability. The analysis shows a high incidence of anaprop in summer, mainly in the morning and evening, due to the humid and hot summer climate of the Po Valley, particularly in the coastal zone. Thereafter, a comparison between different techniques and datasets to retrieve the vertical profile of the refractive index gradient in the boundary layer is also presented. In particular, their capability to detect anomalous propagation conditions is compared. Furthermore, beam path trajectories are simulated using a multilayer ray-tracing model and the influence of the propagation conditions on the beam trajectory and shape is examined. High resolution radiosounding data are identified as the best available dataset to reproduce accurately the local propagation conditions, while lower resolution standard TEMP data suffers from interpolation degradation and Numerical Weather Prediction model data (Lokal Model) are able to retrieve a tendency to superrefraction but not to detect ducting conditions. Observing the ray tracing of the centre, lower and upper limits of the radar antenna 3-dB half-power main beam lobe it is concluded that ducting layers produce a change in the measured volume and in the power distribution that can lead to an additional error in the reflectivity estimate and, subsequently, in the estimated rainfall rate.
On the use of radar reflectivity for estimation of the areal reduction factor
Authors: Lombardo F. , Napolitano F. , Russo F.
Published: April 2010

Abstract. In order to estimate the rainfall fields over an entire basin raingauge, pointwise measurements need to be interpolated and the small-scale variability of rainfall fields can lead to biases in the rain rate estimation over an entire basin, above all for small or medium size mountainous and urban catchments. For these reasons, several raingauges should be installed in different places in order to determine the spatial rainfall distribution during the evolution of the natural phenomena over the selected area. In technical applications, many empirical relations are used in order to deduce heavy areal rainfall, when just one raingauge is available. In this work, we studied the areal reduction factor (ARF) using radar reflectivity maps collected with the Polar 55C, a C-band Doppler dual polarized coherent weather radar with polarization agility and with a 0.9° beamwidth. The radar rainfall estimates, for an area of 1 km2, were integrated for heavy rainfall with an upscaling process, until we had rainfall estimate for an area of 900 km2. The results obtained for a significant amount of data by using this technique are compared with the most important relations of the areal reduction factor reported in the literature.
The impact of the climate change on discharge of Suir River Catchment (Ireland) under different climate scenarios
Authors: Wang S. , McGrath R. , Semmler T. , Sweeney C. , Nolan P.
Published: April 2010

Abstract. The impact of climate change on local discharge variability is investigated in the Suir River Catchment which is located in the south-east of Ireland. In this paper, the Rossby Centre Regional Atmospheric Model (RCA) is driven by different global climate data sets. For the past climate (1961–2000), the model is driven by ECMWF reanalysis (ERA-40) data as well as by the output of the general circulation models (GCM's) ECHAM4 and ECHAM5. For the future simulation (2021–2060), the model is driven by two GCM scenarios: ECHAM4_B2 and ECHAM5_A2. To investigate the influence of changed future climate on local discharge, the precipitation of the model output is used as input for the HBV hydrological model. The calibration and validation results of our ERA-40 driven present day simulation shows that the HBV model can reproduce the discharge fairly well, except the extreme discharge is systematically underestimated by about 15–20%. Altogether the application of a high resolution regional climate model in connection with a conceptual hydrological model is capable of capturing the local variability of river discharge for present-day climate using boundary values assimilated with observations such as ERA-40 data. However, using GCM data to drive RCA and HBV suggests, that there is still large uncertainty connected with the GCM formulation: For present day climate the validation of the ECHAM4 and ECHAM5 driven simulations indicates stronger discharge compared to the observations due to overprediction of precipitation, especially for the ECHAM5 driven simulation in the summer season. Whereas according to the ECHAM4_B2 scenario the discharge generally increases – most pronounced in the wet winter time, there are only slight increases in winter and considerable decreases in summer according to the ECHAM5_A2 scenario. This also leads to a different behaviour in the evolution of return levels of extreme discharge events: Strong increases according to the ECHAM4_B2 scenario and slight decreases according to the ECHAM5_A2 scenario.
Analysis of severe convective events from two operational dual polarisation doppler radars
Authors: Celano M. , Alberoni P. P. , Levizzani V. , Holt A. R.
Published: April 2010

Abstract. The recent gradual increase in the use of polarimetric radars prompts for possible improvements in the estimation of precipitation and the identification of the prevailing hydrometeor type. An analysis of different convection episodes (20 May 2003, 4 and 7 May 2004) is conducted in order to explore the attenuation effects at C band and their consequences on the rainfall field estimation using two polarimetric radars in the Po Valley, Italy, located about 90 km apart. A hydrometeor classification scheme, developed at the National Severe Storms Laboratory (NSSL), is used to detect the microphysical structure of the different cloud systems. The work is focused on the reconstruction of the 3-D organisation of the convective events, highlighting how the two radar systems ''see'' the storms from different points of view. Furthermore, the two distinct observations and the temperature field are used to correct the effect of attenuation.
Modulation of homogeneous space-time rainfall cascades to account for orographic influences
Authors: Badas M. G. , Deidda R. , Piga E.
Published: April 2010

Abstract. The development of efficient space-time rainfall downscaling procedures is highly important for the implementation of a meteo-hydrological forecasting chain operating over small watersheds. Multifractal models based on homogeneous cascade have been successfully applied in literature to reproduce space-time rainfall events retrieved over ocean, where the hypothesis of spatial homogeneity can be reasonably accepted. The feasibility to apply this kind of models to rainfall fields occurring over a mountainous region, where spatial homogeneity may not hold, is herein investigated. This issue is examined through the analysis of rainfall data retrieved by the high temporal resolution rain gage network of the Sardinian Hydrological Survey. The proposed procedure involves the introduction of a modulating function which is superimposed to homogeneous and isotropic synthetic fields to take into account the spatial heterogeneity detected in observed precipitation events. Specifically the modulating function, which reproduces the differences in local mean values of the precipitation intensity probability distribution, has been linearly related to the terrain elevation of the analysed spatial domain. Comparisons performed between observed and synthetic data show how the proposed procedure preserves the observed rainfall fields features and how the introduction of the modulating function improves the reproduction of spatial heterogeneity in rainfall probability distributions.
The effect of scale in daily precipitation hazard assessment
Authors: Egozcue J. J. , Pawlowsky-Glahn V. , Ortego M. I. , Tolosana-Delgado R.
Published: April 2010

Abstract. Daily precipitation is recorded as the total amount of water collected by a rain-gauge in 24 h. Events are modelled as a Poisson process and the 24 h precipitation by a Generalised Pareto Distribution (GPD) of excesses. Hazard assessment is complete when estimates of the Poisson rate and the distribution parameters, together with a measure of their uncertainty, are obtained. The shape parameter of the GPD determines the support of the variable: Weibull domain of attraction (DA) corresponds to finite support variables as should be for natural phenomena. However, Fréchet DA has been reported for daily precipitation, which implies an infinite support and a heavy-tailed distribution. Bayesian techniques are used to estimate the parameters. The approach is illustrated with precipitation data from the Eastern coast of the Iberian Peninsula affected by severe convective precipitation. The estimated GPD is mainly in the Fréchet DA, something incompatible with the common sense assumption of that precipitation is a bounded phenomenon. The bounded character of precipitation is then taken as a priori hypothesis. Consistency of this hypothesis with the data is checked in two cases: using the raw-data (in mm) and using log-transformed data. As expected, a Bayesian model checking clearly rejects the model in the raw-data case. However, log-transformed data seem to be consistent with the model. This fact may be due to the adequacy of the log-scale to represent positive measurements for which differences are better relative than absolute.
Influence of rheology on debris-flow simulation
Authors: Arattano M. , Franzi L. , Marchi L.
Published: April 2010

Abstract. Systems of partial differential equations that include the momentum and the mass conservation equations are commonly used for the simulation of debris flow initiation, propagation and deposition both in field and in laboratory research. The numerical solution of the partial differential equations can be very complicated and consequently many approximations that neglect some of their terms have been proposed in literature. Many numerical methods have been also developed to solve the equations. However we show in this paper that the choice of a reliable rheological model can be more important than the choice of the best approximation or the best numerical method to employ. A simulation of a debris flow event that occurred in 2004 in an experimental basin on the Italian Alps has been carried out to investigate this issue. The simulated results have been compared with the hydrographs recorded during the event. The rheological parameters that have been obtained through the calibration of the mathematical model have been also compared with the rheological parameters obtained through the calibration of previous events, occurred in the same basin. The simulation results show that the influence of the inertial terms of the Saint-Venant equation is much more negligible than the influence of the rheological parameters and the geometry. A methodology to quantify this influence has been proposed.
Estimation of the regional stock of residential buildings as a basis for a comparative risk assessment in Germany
Authors: Kleist L. , Thieken A. H. , Köhler P. , Müller M. , Seifert I. , Borst D. , Werner U.
Published: April 2010

Abstract. One important prerequisite for a comparable quantitative risk assessment for different types of hazards (e.g., earthquakes, windstorms and floods) is the use of a common database about and financial appraisal of the assets at risk. For damage assessments it is necessary to represent the values at risk on a regional disaggregated scale and to intersect them with hazard scenarios. This paper presents a methodology and results of a financial appraisal of residential buildings for all communities in Germany. The calculated values are defined as replacement values for the reference year 2000. The resulting average replacement costs for residential buildings per inhabitant amount to EUR 46 600, with considerable differences between communities. The inventory can be used for the calculations of direct losses from various natural disasters within the project "Risk Map Germany''.
Spatio-temporal precipitation error propagation in runoff modelling: a case study in central Sweden
Authors: Olsson J.
Published: April 2010

Abstract. The propagation of spatio-temporal errors in precipitation estimates to runoff errors in the output from the conceptual hydrological HBV model was investigated. The study region was the Gimån catchment in central Sweden, and the period year 2002. Five precipitation sources were considered: NWP model (H22), weather radar (RAD), precipitation gauges (PTH), and two versions of a mesoscale analysis system (M11, M22). To define the baseline estimates of precipitation and runoff, used to define seasonal precipitation and runoff biases, the mesoscale climate analysis M11 was used. The main precipitation biases were a systematic overestimation of precipitation by H22, in particular during winter and early spring, and a pronounced local overestimation by RAD during autumn, in the western part of the catchment. These overestimations in some cases exceeded 50% in terms of seasonal subcatchment relative accumulated volume bias, but generally the bias was within ±20%. The precipitation data from the different sources were used to drive the HBV model, set up and calibrated for two stations in Gimån, both for continuous simulation during 2002 and for forecasting of the spring flood peak. In summer, autumn and winter all sources agreed well. In spring H22 overestimated the accumulated runoff volume by ~50% and peak discharge by almost 100%, owing to both overestimated snow depth and precipitation during the spring flood. PTH overestimated spring runoff volumes by ~15% owing to overestimated winter precipitation. The results demonstrate how biases in precipitation estimates may exhibit a substantial space-time variability, and may further become either magnified or reduced when applied for hydrological purposes, depending on both temporal and spatial variations in the catchment. Thus, the uncertainty in precipitation estimates should preferably be specified as a function of both time and space.
Rainfall downscaling and flood forecasting: a case study in the Mediterranean area
Authors: Rebora N. , Ferraris L. , von Hardenberg J. , Provenzale A.
Published: April 2010

Abstract. The prediction of the small-scale spatial-temporal pattern of intense rainfall events is crucial for flood risk assessment in small catchments and urban areas. In the absence of a full deterministic modelling of small-scale rainfall, it is common practice to resort to the use of stochastic downscaling models to generate ensemble rainfall predictions to be used as inputs to rainfall-runoff models. In this work we present an application of a new spatial-temporal downscaling procedure, called RainFARM, to an intense precipitation event predicted by the limited-area meteorological model Lokal Model over north-west Italy. The uncertainty in flood prediction associated with the small unresolved scales of forecasted precipitation fields is evaluated by using an ensemble of downscaled fields to drive a semi-distributed rainfall-runoff model.
Reactivation hazard mapping for ancient landslides in West Belgium
Authors: Dewitte O. , Chung C.-J. , Demoulin A.
Published: April 2010

Abstract. Several examples in western Europe have shown that, at least for deep-seated rotational slides, reactivation of formerly slipped masses is a more frequent phenomenon than the occurrence of new landslides, therefore representing a higher hazard. We selected a study area comprised of 13 landslides located in the Flemish Ardennes (West Belgium) and predicted the hazard related to scarp retreat. The scarp reactivations were identified from the comparison of DTMs produced for 1952 and 1996. Robust results were obtained with the Gamma operator of a fuzzy set approach and a combination of geomorphic, topographic and land use data. We built first a prediction model from the relations linking the 1952–1996 retreat events to the conditioning parameters of 1952. The prediction rate of the resulting susceptibility map is estimated by a cross-validation procedure. We then applied the statistics of this model to the data of 1996 in order to produce a susceptibility map responding to the present-day conditions. Finally, we estimated the conditional probabilities of occurrence of future reactivations for the period 1996–2036.
Enhanced radar precipitation estimates using a combined clutter and beam blockage correction technique
Authors: Fornasiero A. , Bech J. , Alberoni P. P.
Published: April 2010

Abstract. Weather radar observations are currently the most reliable method for remote sensing of precipitation. However, a number of factors affect the quality of radar observations and may limit seriously automated quantitative applications of radar precipitation estimates such as those required in Numerical Weather Prediction (NWP) data assimilation or in hydrological models. In this paper, a technique to correct two different problems typically present in radar data is presented and evaluated. The aspects dealt with are non-precipitating echoes – caused either by permanent ground clutter or by anomalous propagation of the radar beam (anaprop echoes) – and also topographical beam blockage. The correction technique is based in the computation of realistic beam propagation trajectories based upon recent radiosonde observations instead of assuming standard radio propagation conditions. The correction consists of three different steps: 1) calculation of a Dynamic Elevation Map which provides the minimum clutter-free antenna elevation for each pixel within the radar coverage; 2) correction for residual anaprop, checking the vertical reflectivity gradients within the radar volume; and 3) topographical beam blockage estimation and correction using a geometric optics approach. The technique is evaluated with four case studies in the region of the Po Valley (N Italy) using a C-band Doppler radar and a network of raingauges providing hourly precipitation measurements. The case studies cover different seasons, different radio propagation conditions and also stratiform and convective precipitation type events. After applying the proposed correction, a comparison of the radar precipitation estimates with raingauges indicates a general reduction in both the root mean squared error and the fractional error variance indicating the efficiency and robustness of the procedure. Moreover, the technique presented is not computationally expensive so it seems well suited to be implemented in an operational environment.
Winter storm risk of residential structures – model development and application to the German state of Baden-Württemberg
Authors: Heneka P. , Hofherr T. , Ruck B. , Kottmeier C.
Published: April 2010

Abstract. The derivation of probabilities of high wind speeds and the establishment of risk curves for storm damage is of prime importance in natural hazard risk analysis. Risk curves allow the assessment of damage being exceeded at a given level of probability. In this paper, a method for the assessment of winter storm damage risk is described in detail and applied to the German state of Baden-Württemberg. Based on meteorological observations of the years 1971–2000 and on damage information of 4 severe storm events, storm hazard and damage risk of residential buildings is calculated on the level of communities. For this purpose, highly resolved simulations of storm wind fields with the Karlsruher Atmospheric Mesoscale Model (KAMM) are performed and a storm damage model is developed. Risk curves including the quantification of the uncertainties are calculated for every community. Local differences of hazard and risk are presented in state-wide maps. An average annual winter storm damage to residential buildings of minimum 15 million Euro (reference year 2000) for Baden-Württemberg is expected.
On Es-spread effects in the ionosphere connected to earthquakes
Authors: Liperovskaya E. V. , Meister C.-V. , Pokhotelov O. A. , Parrot M. , Bogdanov V. V. , Vasil'eva N. E.
Published: April 2010

Abstract. In the present work, phenomena in the ionosphere are studied, which are connected with earthquakes (16 events) having a depth of less than 50 km and a magnitude M larger than 4. Analysed are night-time Es-spread effects using data of the vertical sounding station Petropavlovsk-Kamchatsky (φ=53.0°, λ=158.7°) from May 2004 until August 2004 registered every 15 min. It is found that the maximum distance of the earthquake from the sounding station, where pre-seismic phenomena are yet observable, depends on the magnitude of the earthquake. Further it is shown that 1–2 days before the earthquakes, in the pre-midnight hours, the appearance of Es-spread increases. With a probability of more than 0.95, this increase of Es-spread observations before midnight is not casual.
Geology, glacier retreat and permafrost degradation as controlling factors of slope instabilities in a high-mountain rock wall: the Monte Rosa east face
Authors: Fischer L. , Kääb A. , Huggel C. , Noetzli J.
Published: April 2010

Abstract. The Monte Rosa east face, Italian Alps, is one of the highest flanks in the Alps (2200–4500 m a.s.l.). Steep hanging glaciers and permafrost cover large parts of the wall. Since the end of the Little Ice Age (about 1850), the hanging glaciers and firn fields have retreated continuously. During recent decades, the ice cover of the Monte Rosa east face experienced an accelerated and drastic loss in extent. Some glaciers have completely disappeared. New slope instabilities and detachment zones of gravitational mass movements developed and enhanced rock fall and debris flow activity was observed. This study is based on multidisciplinary investigations and shows that most of the detachment zones of rock fall and debris flows are located in areas, where the surface ice disappeared only recently. Furthermore, most of these detachment zones are located in permafrost zones, for the most part close to the modelled and estimated lower boundary of the regional permafrost distribution. In the view of ongoing or even enhanced atmospheric warming and associated changes it is therefore very likely that the slope instabilities in the Monte Rosa east face will continue to represent a critical hazard source.
Characterisation of weathered clayey soils responsible for shallow landslides
Authors: Meisina C.
Published: April 2010

Abstract. Shallow earth translational slides and earth flows, affecting colluvial soils derived by the weathering of the clayey bedrock, are a recurrent problem causing damage to buildings and roads in many areas of Apennines. The susceptibility assessment, e.g. slope stability models, requires the preliminary characterization of these superficial covers (lithology, geotechnical and hydraulic parameters). The aim of the work is to develop and test a methodology for the identification and mapping of weathered clayey soils responsible for shallow landslides. A test site in Northern Apennines (Province of Pavia) was selected. Argillaceous and marly successions characterize the area. Shallow landslides occurred periodically due to high intensity rainfalls. Trench pits were used for the soil profile description (lithology, structure, grade of weathering, thickness) and sampling. The main geological, topographic and geomorphologic parameters of shallow landslides were analysed. Field surveys were integrated with some geotechnical laboratory tests (index properties, suction and volumetric characteristic determination, methylene blue adsorption test, linear shrinkage, swell strain). Engineering geological zoning was carried out by grouping the superficial soils on the basis of the following attributes: topographic conditions (slope angle), landslide occurrence, lithology (grain size), geometry (thickness), lithology of the bedrock, hydrogeological and geotechnical characteristics. The resulting engineering-geological units (areas that may be regarded as homogeneous from the geomorphologic and engineering – geological point of view) were analysed in terms of shallow slope instability.
The disastrous storm of 4 November 1966 on Italy
Authors: De Zolt S. , Lionello P. , Nuhu A. , Tomasin A.
Published: April 2010

Abstract. This is the first modeling reconstruction of the whole aspects (both meteorological and oceanographic) of the storm which hit Italy on 4 November 1966, producing 118 victims and widespread damages in Tuscany, at the northern Adriatic coast and in the north-eastern Italian Alps. The storm was produced by a cyclone which formed in the western Mediterranean and moved eastward towards Italy, reaching the Thyrrenian Sea, and then northward. The most peculiar characteristic of the storm has been the strong zonal pressure gradient and the consequent intensity and long fetch of the south-easterly sirocco wind, which advected a large amount of warm moist air, and determined exceptional orographic precipitation over Tuscany and the north-eastern Alps. The funneling of the wind between the mountain chains surrounding the Adriatic basin further increased the wind speed and determined the highest ever recorded storm surge along the Venetian coast. This study shows that present models would be able to produce a reasonably accurate simulation of the meteorological event (surface pressure, wind and precipitation fields, and storm surge level). The exceptional intensity of the event is not suggested by single parameters such as the sea level pressure minimum, the wind speed or the total accumulated precipitation. In fact, the precipitation was extreme only in some locations and the pressure minimum was not particularly deep. Moreover, the prediction of the damages produced by the river run-off and landslides would have required other informations concerning soil condition, snow coverage, and storage of water reservoirs before the event. This indicates that an integrated approach is required for assessing the probability of such damages both on a weather forecast and on a climate change perspective.
Wavelet analysis on pressure stimulated currents emitted by marble samples
Authors: Kyriazis P. , Anastasiadis C. , Triantis D. , Vallianatos F.
Published: April 2010

Abstract. This paper presents a wavelet based method of analysis of experimentally recorded weak electric signals from marble specimens which have undergone successive abrupt step loadings. Experimental results verify the existence of "memory effects" in rocks, as far as the current emission is concerned, akin to the "Kaiser effect" in acoustic emissions, which accompany rock fracturing. Macroscopic signal processing shows similarities and differences between the currents emitted during successive loading and wavelet analysis can reveal significant differences between the currents of each loading cycle that contain valuable information for the micro and macro cracks in the specimen as well as information for the remaining strength of the material. Wavelets make possible the time localization of the energy of the electric signal emitted by stressed specimens and can serve as method to differentiate between compressed and uncompressed samples, or to determine the deformation level of specimens.
Stability of saprolitic slopes: nature and role of field scale heterogeneities
Authors: Aydin A.
Published: April 2010

Abstract. Heterogeneities in various forms and scales often control the mechanisms and locations of failure and deformation, and the factor of safety of saprolitic slopes. This paper presents a critical review of field scale heterogeneities and their roles in controlling the stability of saprolitic slopes. In particular corestones and relict joints are analysed, with emphasis on characterization and possible instability modes. Abnormal flow patterns, fast build-up and/or chaotic distribution of pore water pressure are the most common causative factors of landslides. As heterogeneities are often responsible for the occurrence of such localized abnormalities, realistic models incorporating effects of these features can help predict how and where abnormal flow/pressure patterns may develop. Potential pitfalls during ground investigation in landslide prone slopes are elucidated and effective investigation strategies to avoid these pitfalls are recommended. The uncertainties, for example, in distribution and volumetric percentage of corestones and in delineating zonal boundaries, require continuous upgrading of the engineering geological model during the construction stage of site investigations. Such uncertainties can be reduced in a cost-effective manner by recording drill penetration rates during installation of soil nails and horizontal drains. A better understanding of the interactions among the heterogeneities, the matrix and the engineering geological environment as a whole should enable the significance of discrete features in stability to be more consistently assessed, thereby providing a more rational basis for investigation and design practice in saprolitic profiles.
On the singular values decoupling in the Singular Spectrum Analysis of volcanic tremor at Stromboli
Authors: Carniel R. , Barazza F. , Tárraga M. , Ortiz R.
Published: April 2010

Abstract. The well known strombolian activity at Stromboli volcano is occasionally interrupted by rarer episodes of paroxysmal activity which can lead to considerable hazard for Stromboli inhabitants and tourists. On 5 April 2003 a powerful explosion, which can be compared in size with the latest one of 1930, covered with bombs a good part of the normally tourist-accessible summit area. This explosion was not forecasted, although the island was by then effectively monitored by a dense deployment of instruments. After having tackled in a previous paper the problem of highlighting the timescale of preparation of this event, we investigate here the possibility of highlighting precursors in the volcanic tremor continuously recorded by a short period summit seismic station. We show that a promising candidate is found by examining the degree of coupling between successive singular values that result from the Singular Spectrum Analysis of the raw seismic data. We suggest therefore that possible anomalies in the time evolution of this parameter could be indicators of volcano instability to be taken into account e.g. in a bayesian eruptive scenario evaluator. Obviously, further (and possibly forward) testing on other cases is needed to confirm the usefulness of this parameter.
Spatially explicit avalanche risk assessment linking Bayesian networks to a GIS
Authors: Grêt-Regamey A. , Straub D.
Published: April 2010

Abstract. Avalanche disasters are associated with significant monetary losses. It is thus crucial that avalanche risk assessments are based on a consistent and proper assessment of the uncertainties involved in the modelling of the avalanche run-out zones and the estimations of the damage potential. We link a Bayesian network (BN) to a Geographic Information System (GIS) for avalanche risk assessment in order to facilitate the explicit modelling of all relevant parameters, their causal relations and the involved uncertainties in a spatially explicit manner. The suggested procedure is illustrated for a case study area (Davos, Switzerland) located in the Swiss Alps. We discuss the potential of such a model by comparing the risks estimated using the probabilistic framework to those obtained by a traditional risk assessment procedure. The presented model may serve as a basis for developing a consistent and unified risk assessment approach.