bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupling of high-resolution meteorological and wave models over southern Italy
Authors: Bertotti L. , Miglietta M. M. , Davolio S.
Published: April 2010

Abstract. In the framework of RISKMED project, three different high-resolution limited area meteorological models (BOLAM, MOLOCH and WRF) have been run over southern Italy for the retrospective analysis of three case studies characterized by strong winds and severe wave conditions in the Ionian, southern Adriatic and southern Tyrrhenian seas. All the models were able to reproduce the main meteorological features of each event. The wind fields simulated by the meteorological models and those provided by the ECMWF analysis have been ingested into a wave model (WAM) for the hindcast of the main wave parameters. The results have been compared with the observations of three buoys whose measurements were available in the area of interest. A remarkable improvement in the representation of the significant wave height came out using the limited area model data with respect to the simulations where the ECMWF analyses were used as forcing. Among the limited area models, the BOLAM-MOLOCH modelling system provided slightly better performances. From the limited set of simulations, the different model predictions came out closer to each other and more skilful in areas where the waves approach the coastline perpendicularly from the open sea.
Coupled modelling of subsurface water flux for an integrated flood risk management
Authors: Sommer T. , Karpf C. , Ettrich N. , Haase D. , Weichel T. , Peetz J.-V. , Steckel B. , Eulitz K. , Ullrich K.
Published: April 2010

Abstract. Flood events cause significant damage not only on the surface but also underground. Infiltration of surface water into soil, flooding through the urban sewer system and, in consequence, rising groundwater are the main causes of subsurface damage. The modelling of flooding events is an important part of flood risk assessment. The processes of subsurface discharge of infiltrated water necessitate coupled modelling tools of both, surface and subsurface water fluxes. Therefore, codes for surface flooding, for discharge in the sewerage system and for groundwater flow were coupled with each other. A coupling software was used to amalgamate the individual programs in terms of mapping between the different model geometries, time synchronization and data exchange. The coupling of the models was realized on two scales in the Saxon capital of Dresden (Germany). As a result of the coupled modelling it could be shown that surface flooding dominates processes of any flood event. Compared to flood simulations without coupled modelling no substantial changes of the surface inundation area could be determined. Regarding sewerage, the comparison between the influx of groundwater into sewerage and the loading due to infiltration by flood water showed infiltration of surface flood water to be the main reason for sewerage overloading. Concurrent rainfalls can intensify the problem. The infiltration of the sewerage system by rising groundwater contributes only marginally to the loading of the sewerage and the distribution of water by sewerage has only local impacts on groundwater rise. However, the localization of risk areas due to rising groundwater requires the consideration of all components of the subsurface water fluxes. The coupled modelling has shown that high groundwater levels are the result of a multi-causal process that occurs before and during the flood event.
The use of questionnaires for acquiring information on public perception of natural hazards and risk mitigation – a review of current knowledge and practice
Authors: Bird D. K.
Published: April 2010

Abstract. Questionnaires are popular and fundamental tools for acquiring information on public knowledge and perception of natural hazards. Questionnaires can provide valuable information to emergency management agencies for developing risk management procedures. Although many natural hazards researchers describe results generated from questionnaires, few explain the techniques used for their development and implementation. Methodological detail should include, as a minimum, response format (open/closed questions), mode of delivery, sampling technique, response rate and access to the questionnaire to allow reproduction of or comparison with similar studies. This article reviews current knowledge and practice for developing and implementing questionnaires. Key features include questionnaire design, delivery mode, sampling techniques and data analysis. In order to illustrate these aspects, a case study examines methods chosen for the development and implementation of questionnaires used to obtain information on knowledge and perception of volcanic hazards in a tourist region in southern Iceland. Face-to-face interviews highlighted certain issues with respect to question structure and sequence. Recommendations are made to overcome these problems before the questionnaires are applied in future research projects. In conclusion, basic steps that should be disclosed in the literature are provided as a checklist to ensure that reliable, replicable and valid results are produced from questionnaire based hazard knowledge and risk perception research.
A web-based GIS for managing and assessing landslide data for the town of Peace River, Canada
Authors: Lan H. X. , Martin C. D. , Froese C. R. , Kim T. H. , Morgan A. J. , Chao D. , Chowdhury S.
Published: April 2010

Abstract. Assessment of geological hazards in urban areas must integrate geospatial and temporal data, such as complex geology, highly irregular ground surface, fluctuations in pore-water pressure, surface displacements and environmental factors. Site investigation for geological hazard studies frequently produces surface maps, geological information from borehole data, laboratory test results and monitoring data. Specialized web-based GIS tools were created to facilitate geospatial analyses of displacement data from inclinometers and pore pressure data from piezometers as well as geological information from boreholes and surface mapping. A variety of visual aids in terms of graphs or charts can be created in the web page on the fly, e.g. displacement vector, time displacement and summaries of geotechnical testing results. High-resolution satellite or aerial images and LiDAR data can also be effectively managed, facilitating fast and preliminary hazard assessment. A preliminary geohazard assessment using the web based tools was carried out for the Town of Peace River.
Fog characteristics at the airport of Thessaloniki, Greece
Authors: Stolaki S. N. , Kazadzis S. A. , Foris D. V. , Karacostas Th. S.
Published: April 2010

Abstract. A statistical approach in order to study fog event characteristics occuring at the airport of Thessaloniki, Northern Greece is presented in this work. To achieve this, the seasonal and diurnal characteristics of fog are investigated using 35 years (1971–2005) of observations of meteorological parameters such as: visibility, air temperature, dew point temperature, air relative humidity, wind vector, precipitation, and cloud base height and coverage. Hourly surface observations of fifteen (15) years (1991–2005) are used to identify fog events induced by various physical mechanisms. Fog events are classified into fog types through the application of objective criteria that are derived upon fog formation processes and under the influence of various physiographic features. The temporal variability of different fog type occurrences are examined and the events are characterized according to their duration and intensity. The results are somehow affected by regional and local factors. Fog is mainly formed in winter time (~64%) with an enhanced likelihood to appear also in late autumn (19%). The highest frequency of the fog events occurs around sunrise or 1 to 2 h before of it. The mean duration of the events is about 4.5 h. Most of them (75%) are dense (visibility <400 m). The overall fog phenomenon is a combination of various types, such as: advection fog, radiation fog, cloud-base lowering fog and precipitation fog. Advection fog (30%) and radiation fog (29%), which are the most common types, occur predominantly in winter and early spring time. With respect to the former type, it seems that, in many cases, already formed fog is advected from the nearby Anthemountas valley. Moreover, a considerable number of fog events (22%) result from cloud-base lowering, and they frequently occur in late autumn and mid winter.
Seismogenic zonation and seismic hazard estimates in a Southern Italy area (Northern Apulia) characterised by moderate seismicity rates
Authors: Del Gaudio V. , Pierri P. , Calcagnile G.
Published: April 2010

Abstract. The northernmost part of Apulia, in Southern Italy, is an emerged portion of the Adriatic plate, which in past centuries was hit by at least three disastrous earthquakes and at present is occasionally affected by seismic events of moderate energy. In the latest seismic hazard assessment carried out in Italy at national scale, the adopted seismogenic zonation (named ZS9) has defined for this area a single zone including parts of different structural units (chain, foredeep, foreland). However significant seismic behaviour differences were revealed among them by our recent studies and, therefore, we re-evaluated local seismic hazard by adopting a zonation, named ZNA, modifying the ZS9 to separate areas of Northern Apulia belonging to different structural domains. To overcome the problem of the limited datasets of historical events available for small zones having a relatively low rate of earthquake recurrence, an approach was adopted that integrates historical and instrumental event data. The latter were declustered with a procedure specifically devised to process datasets of low to moderate magnitude shocks. Seismicity rates were then calculated following alternative procedural choices, according to a "logic tree" approach, to explore the influence of epistemic uncertainties on the final results and to evaluate, among these, the importance of the uncertainty in seismogenic zonation. The comparison between the results obtained using zonations ZNA and ZS9 confirms the well known "spreading effect" that the use of larger seismogenic zones has on hazard estimates. This effect can locally determine underestimates or overestimates by amounts that make necessary a careful reconsideration of seismic classification and building code application.
Identification of potential rockfall source areas at a regional scale using a DEM-based geomorphometric analysis
Authors: Loye A. , Jaboyedoff M. , Pedrazzini A.
Published: April 2010

Abstract. The availability of high resolution Digital Elevation Models (DEM) at a regional scale enables the analysis of topography with high levels of detail. Hence, a DEM-based geomorphometric approach becomes more accurate for detecting potential rockfall sources. Potential rockfall source areas are identified according to the slope angle distribution deduced from high resolution DEM crossed with other information extracted from geological and topographic maps in GIS format. The slope angle distribution can be decomposed in several Gaussian distributions that can be considered as characteristic of morphological units: rock cliffs, steep slopes, footslopes and plains. A terrain is considered as potential rockfall sources when their slope angles lie over an angle threshold, which is defined where the Gaussian distribution of the morphological unit "Rock cliffs" become dominant over the one of "Steep slopes". In addition to this analysis, the cliff outcrops indicated by the topographic maps were added. They contain however "flat areas", so that only the slope angles values above the mode of the Gaussian distribution of the morphological unit "Steep slopes" were considered. An application of this method is presented over the entire Canton of Vaud (3200 km2), Switzerland. The results were compared with rockfall sources observed on the field and orthophotos analysis in order to validate the method. Finally, the influence of the cell size of the DEM is inspected by applying the methodology over six different DEM resolutions.
CliFEM – Climate Forcing and Erosion Modelling in the Sele River Basin (Southern Italy)
Authors: Diodato N. , Fagnano M. , Alberico I.
Published: April 2010

Abstract. This study presents a revised and scale-adapted Foster-Meyer-Onstad model (Foster et al., 1977) for the transport of soil erosion sediments under scarce input data, with the acronym CliFEM (Climate Forcing and Erosion Modelling). This new idea was addressed to develop a monthly time scale invariant Net Erosion model (NER), with the aim to consider the different erosion processes operating at different time scales in the Sele River Basin (South Italy), during 1973–2007 period. The sediment delivery ratio approach was applied to obtain an indirect estimate of the gross erosion too. The examined period was affected by a changeable weather regime, where extreme events may have contributed to exacerbate soil losses, although only the 19% of eroded sediment was delivered at outlet of the basin. The long-term average soil erosion was very high (73 Mg ha−1 per year ± 58 Mg ha−1). The estimate of monthly erosion showed catastrophic soil losses during the soil tillage season (August–October), with consequent land degradation of the hilly areas of the Sele River Basin.
Flow-type failures in fine-grained soils: an important aspect in landslide hazard analysis
Authors: van Asch T. W. J. , Malet J.-P.
Published: April 2010

Abstract. Forecasting the possibility of flow-type failures within a slow-moving landslide mass is rarely taken into account in quantitative hazard assessments. Therefore, this paper focuses on the potential transition of sliding blocks (slumps) into flow-like processes due to the generation of excess pore water pressure in undrained conditions. The generation of excess pore water pressure may be the consequence of deformation of the landslide body during motion. Two model concepts are proposed and discussed. The first concept is the so called strain concept model where emphasis is laid on strain changes due to differential movement within the moving mass. This may create zones of compression and dilation and consequently excess pore water pressures. The second concept is the so called topographical concept model which focuses on changes in the stress field of the landslide caused by geometric changes in topography of the moving body. Both models were tested on two slumps which developed in secondary scarps of the Super-Sauze mudslide in the Barcelonnette Basin (South French Alps). The slump which developed in 1999 showed complete fluidization; all the material was removed from the source area and transformed into a mudflow. The second slump, dated from 2006, did not show fluidization; it has a relative short displacement and all the material remained in the source area. It appeared that the strain concept model predicted flow-type failure for both slumps, after relative short displacements, while the topographical concept model predicted only flow-type failure for the 1999 slump and not for the 2006 slump. The strain concept model seems too conservative in forecasting the fluidization potential of slumping blocks.
Methodology to evaluate rock slope stability under seismic conditions at Solà de Santa Coloma, Andorra
Authors: Mavrouli O. , Corominas J. , Wartman J.
Published: April 2010

Abstract. An analytical methodology is presented to evaluate rock slope stability under seismic conditions by considering the geomechanical and topographic properties of a slope. The objective is to locate potential rockfall source areas and evaluate their susceptibility in terms of probability of failure. For this purpose, the slope face of a study area is discretized into cells having homogenous aspect, slope angle, rock properties and joint set orientations. A pseudostatic limit equilibrium analysis is performed for each cell, whereby the destabilizing effect of an earthquake is represented by a horizontal force. The value of this force is calculated by linear interpolation between the peak horizontal ground acceleration PGA at the base and the top of the slope. The ground acceleration at the top of the slope is increased by 50% to account for topographic amplification. The uncertainty associated with the joint dip is taken into account using the Monte Carlo method. The proposed methodology was applied to a study site with moderate seismicity in Solà de Santa Coloma, located in the Principality of Andorra. The results of the analysis are consistent with the spatial distribution of historical rockfalls that have occurred since 1997. Moreover, the results indicate that for the studied area, 1) the most important factor controlling the rockfall susceptibility of the slope is water pressure in joints and 2) earthquake shaking with PGA of ≤0.16 g will cause a significant increase in rockfall activity only if water levels in joints are greater than 50% of the joint height.
Drought and vegetation stress monitoring in Portugal using satellite data
Authors: Gouveia C. , Trigo R. M. , DaCamara C. C.
Published: April 2010

Abstract. Remote sensed information on vegetation and soil moisture, namely the Normalised Difference Vegetation Index (NDVI) and the Soil Water Index (SWI), is employed to monitor the spatial extent, severity and persistence of drought episodes over Continental Portugal, from 1999 to 2006. The severity of a given drought episode is assessed by evaluating the cumulative impact over time of drought conditions on vegetation. Special attention is given to the drought episodes that have occurred in the last decade, i.e., 1999, 2002 and particularly the major event of 2005. During both the 1999 and 2005 drought episodes negative anomalies of NDVI are observed over large sectors of Southern Portugal for up to nine months (out of eleven) of the vegetative cycle. On the contrary, the 2002 event was characterized by negative anomalies in the northern half of Portugal and for a shorter period (eight out of eleven months). The impact of soil moisture on vegetation dynamics is evaluated by analyzing monthly anomalies of SWI and by studying the annual cycle of SWI vs. NDVI. While in the case of the drought episode of 1999 the scarcity of water in the soil persisted until spring, in the recent episode of 2005 the deficit in greenness was already apparent at the end of summer. The impact of dry periods on vegetation is clearly observed in both arable land and forest, and it is found that arable land presents a higher sensitivity. From an operational point of view, obtained results reveal the possibility of using the developed methodology to monitor, in quasi real-time, vegetation stress and droughts in Mediterranean ecosystems.
Indices of precipitation extremes in Southern Portugal – a geostatistical approach
Authors: Durão R. , Pereira M. J. , Costa A. C. , Côrte-Real J. M. , Soares A.
Published: April 2010

Abstract. Most of the actual studies and previews of future rainfall patterns, based on past observed records for Mediterranean climate areas, focus on the decline of the rainfall amounts over the years, and also on the increase of the frequency of heavy/intense rainfall events particularly in the winter season. These changes in heavy rainfall events may have severe implications and impacts on soil erosion resulting in increased soil degradation risks. The objective of the present work is to evaluate the spatial distribution of extreme precipitation events in Southern Portugal, using a geostatistical approach to assess the relationships between spatial and temporal extreme rainfall patterns. The used dataset comprises a set of 105 stations' records of daily precipitation within the period 1960–1999. Two indices of extreme precipitation were selected to be computed based on the daily precipitation observation series: one representing the frequency of extremely heavy precipitation events (R30) and another one characterizing flood events (R5D). The space-time patterns of the precipitation indices were evaluated and simulated using a geostatistical approach. Despite no significant temporal trends were detected on the calculated indices series, the space-time decadal patterns are becoming more continuous in the last two decades than the previous ones.
Revision of the Portuguese catalog of tsunamis
Authors: Baptista M. A. , Miranda J. M.
Published: April 2010

Abstract. Catastrophic tsunamis are described in historical sources for all regions around the Gulf of Cadiz, at least since 60 BC. Most of the known events are associated with moderate to large earthquakes and among them the better studied is 1 November 1755. We present here a review of the events which effects, on the coasts of the Portuguese mainland and Madeira Island, are well described in historical documents or have been measured by tide gauges since the installation of these instruments. For a few we include new relevant information for the assessment of the tsunami generation or effects, and we discard events that are included in existing compilations but are not supported by quality historical sources or instrumental records. We quote the most relevant quantitative descriptions of tsunami effects on the Portuguese coast, including in all pertinent cases a critical review of the coeval sources, to establish a homogenous event list. When available, instrumental information is presented. We complement all this information with a summary of the conclusions established by paleo-tsunami research.
Flood maps in Europe – methods, availability and use
Authors: de Moel H. , van Alphen J. , Aerts J. C. J. H.
Published: April 2010

Abstract. To support the transition from traditional flood defence strategies to a flood risk management approach at the basin scale in Europe, the EU has adopted a new Directive (2007/60/EC) at the end of 2007. One of the major tasks which member states must carry out in order to comply with this Directive is to map flood hazards and risks in their territory, which will form the basis of future flood risk management plans. This paper gives an overview of existing flood mapping practices in 29 countries in Europe and shows what maps are already available and how such maps are used. Roughly half of the countries considered have maps covering as good as their entire territory, and another third have maps covering significant parts of their territory. Only five countries have very limited or no flood maps available yet. Of the different flood maps distinguished, it appears that flood extent maps are the most commonly produced floods maps (in 23 countries), but flood depth maps are also regularly created (in seven countries). Very few countries have developed flood risk maps that include information on the consequences of flooding. The available flood maps are mostly developed by governmental organizations and primarily used for emergency planning, spatial planning, and awareness raising. In spatial planning, flood zones delimited on flood maps mainly serve as guidelines and are not binding. Even in the few countries (e.g. France, Poland) where there is a legal basis to regulate floodplain developments using flood zones, practical problems are often faced which reduce the mitigating effect of such binding legislation. Flood maps, also mainly extent maps, are also created by the insurance industry in Europe and used to determine insurability, differentiate premiums, or to assess long-term financial solvency. Finally, flood maps are also produced by international river commissions. With respect to the EU Flood Directive, many countries already have a good starting point to map their flood hazards. A flood risk based map that includes consequences, however, has yet to be developed by most countries.
Ionospheric quasi-static electric field anomalies during seismic activity in August–September 1981
Authors: Gousheva M. , Danov D. , Hristov P. , Matova M.
Published: April 2010

Abstract. The paper proposes new results, analyses and information for the plate tectonic situation in the processing of INTERCOSMOS-BULGARIA-1300 satellite data about anomalies of the quasi-static electric field in the upper ionosphere over activated earthquake source regions at different latitudes. The earthquake catalogue is made on the basis of information from the United State Geological Survey (USGS) website. The disturbances in ionospheric quasi-static electric fields are recorded by IESP-1 instrument aboard the INTERCOSMOS-BULGARIA-1300 satellite and they are compared with significant seismic events from the period 14 August–20 September 1981 in magnetically very quiet, quiet and medium quiet days. The main tectonic characteristics of the seismically activated territories are also taken in account. The main goal of the above research work is to enlarge the research of possible connections between anomalous vertical electric field penetrations into the ionosphere and the earthquake manifestations, also to propose tectonic arguments for the observed phenomena. The studies are represented in four main blocks: (i) previous studies of similar problems, (ii) selection of satellite, seismic and plate tectonic data, (iii) data processing with new specialized software and observations of the quasi-static electric field and (iiii) summary, comparison of new with previous results in our studies and conclusion. We establish the high informativity of the vertical component Ez of the quasi-static electric field in the upper ionosphere according observations by INTERCOSMOS-BULGARIA-1300 that are placed above considerably activated earthquake sources. This component shows an increase of about 2–10 mV/m above sources, situated on mobile structures of the plates. The paper discusses the observed effects. It is represented also a statistical study of ionospheric effects 5–15 days before and 5–15 days after the earthquakes with magnitude M 4.8–7.9.
Seismicity anomalies prior to 8 June 2008, Mw=6.4 earthquake in Western Greece
Authors: Chouliaras G.
Published: April 2010

Abstract. The epicentral area of the Mw=6.4, 8 June 2008 main shock in northwestern Peloponesus, Western Greece, had been forecasted as a candidate for the occurrence of a strong earthquake by independent scientific investigations. This study concerns the seismicity of a large area surrounding the epicenter of the main shock using the seismological data from the monthly bulletins of the Institute of Geodynamics of the National Observatory of Athens. This data set is the most detailed earthquake catalog available for anomalous seismicity pattern investigations in Greece. The results indicate a decrease in seismicity rate seven years prior to the 8 June main shock which constituted a two and a half year long seismic quiescence surrounding the epicentral area. This quiescence anomaly was succeeded by a period of acceleration in seismic activity for five years approximately, until the occurrence of the main shock.
Detection of millimetric deformation using a terrestrial laser scanner: experiment and application to a rockfall event
Authors: Abellán A. , Jaboyedoff M. , Oppikofer T. , Vilaplana J. M.
Published: April 2010

Abstract. Terrestrial laser scanning (TLS) is one of the most promising surveying techniques for rockslope characterization and monitoring. Landslide and rockfall movements can be detected by means of comparison of sequential scans. One of the most pressing challenges of natural hazards is combined temporal and spatial prediction of rockfall. An outdoor experiment was performed to ascertain whether the TLS instrumental error is small enough to enable detection of precursory displacements of millimetric magnitude. This consists of a known displacement of three objects relative to a stable surface. Results show that millimetric changes cannot be detected by the analysis of the unprocessed datasets. Displacement measurement are improved considerably by applying Nearest Neighbour (NN) averaging, which reduces the error (1σ) up to a factor of 6. This technique was applied to displacements prior to the April 2007 rockfall event at Castellfollit de la Roca, Spain. The maximum precursory displacement measured was 45 mm, approximately 2.5 times the standard deviation of the model comparison, hampering the distinction between actual displacement and instrumental error using conventional methodologies. Encouragingly, the precursory displacement was clearly detected by applying the NN averaging method. These results show that millimetric displacements prior to failure can be detected using TLS.
Estimating mass-wasting processes in active earth slides – earth flows with time-series of High-Resolution DEMs from photogrammetry and airborne LiDAR
Authors: Corsini A. , Borgatti L. , Cervi F. , Dahne A. , Ronchetti F. , Sterzai P.
Published: April 2010

Abstract. This paper deals with the use of time-series of High-Resolution Digital Elevation Models (HR DEMs) obtained from photogrammetry and airborne LiDAR coupled with aerial photos, to analyse the magnitude of recently reactivated large scale earth slides – earth flows located in the northern Apennines of Italy. The landslides underwent complete reactivation between 2001 and 2006, causing civil protection emergencies. With the final aim to support hazard assessment and the planning of mitigation measures, high-resolution DEMs are used to identify, quantify and visualize depletion and accumulation in the slope resulting from the reactivation of the mass movements. This information allows to quantify mass wasting, i.e. the amount of landslide material that is wasted during reactivation events due to stream erosion along the slope and at its bottom, resulting in sediment discharge into the local fluvial system, and to assess the total volumetric magnitude of the events. By quantifying and visualising elevation changes at the slope scale, results are also a valuable support for the comprehension of geomorphological processes acting behind the evolution of the analysed landslides.
Mitigating mountain hazards in Austria – legislation, risk transfer, and awareness building
Authors: Holub M. , Fuchs S.
Published: April 2010

Abstract. Embedded in the overall concept of integral risk management, mitigating mountain hazards is pillared by land use regulations, risk transfer, and information. In this paper aspects on legislation related to natural hazards in Austria are summarised, with a particular focus on spatial planning activities and hazard mapping, and possible adaptations focussing on enhanced resilience are outlined. Furthermore, the system of risk transfer is discussed, highlighting the importance of creating incentives for risk-aware behaviour, above all with respect to individual precaution and insurance solutions. Therefore, the issue of creating awareness through information is essential, which is presented subsequently. The study results in recommendations of how administrative units on different federal and local levels could increase the enforcement of regulations related to the minimisation of natural hazard risk. Moreover, the nexus to risk transfer mechanisms is provided, focusing on the current compensation system in Austria and some possible adjustments in order to provide economic incentives for (private) investments in mitigation measures, i.e. local structural protection. These incentives should be supported by delivering information on hazard and risk target-oriented to any stakeholder involved. Therefore, coping strategies have to be adjusted and the interaction between prevention and precaution has to be highlighted. The paper closes with recommendations of how these efforts could be achieved, with a particular focus on the situation in the Republic of Austria.
Ground effects and hydrological changes in the Southern Apennines (Italy) in response to the 23 July 1930 earthquake (MS=6.7)
Authors: Esposito E. , Pece R. , Porfido S. , Tranfaglia G.
Published: April 2010

Abstract. The 23 July 1930 earthquake (MS=6.7) in the Southern Apennines (Italy) was a catastrophic event that produced many effects such as surface faulting, fractures, landslides, settlements, hydrological changes, variations in chemical/physical activity related to the volcanic and/or thermal zones and also acoustic and optical phenomena. It is the first great earthquake of the twentieth century that was studied, thanks to the hydrological monitoring network of the Italian Hydrographic Survey (IHS) set up from 1925 to 1929. For this earthquake we analysed the initial IHS hydrometric and pluviometric data, looking for significant anomalies in springs, water wells and mountain streams. Hydrological data relative to rivers, springs and water wells indicate that some changes can be correlated with the earthquake: a post-seismic excess discharge in some streams, pre- and co-seismic decreases in stream flows and water levels in wells, pre- and post-seismic increases in discharges. The pre- and co-seismic stresses and the tectonic deformations were studied in order to find a possible model of interaction between stress state and hydrological variations. The anomalies found in this work can be considered "rebound anomalies", which are the most common precursor reported by many authors and related to increases in porosity and permeability caused by the fracturing that precedes an earthquake. An estimation of the total excess discharge (0.035 km3) caused by the MS=6.7 Irpinia earthquake is consistent with the excess discharge of about 0.01 km3 determined for the Mw=6.9 Loma Prieta earthquake.
Influence of rainfall spatial resolution on flash flood modelling
Authors: Sangati M. , Borga M.
Published: April 2010

Abstract. High resolution radar rainfall fields and a distributed hydrologic model are used to evaluate the sensitivity of flash flood simulations to spatial aggregation of rainfall at catchment scales ranging from 10.5 km2 to 623 km2. The case study focuses on the extreme flash flood occurred on 29 August 2003 on the eastern Italian Alps. Four rainfall spatial resolutions are considered, with grid size equal to 1-, 4-, 8- and 16-km. The influence of rainfall spatial aggregation is examined by using the flow distance as a spatial coordinate, hence emphasising the role of river network in the averaging of space-time rainfall. Effects of rainfall spatial aggregation are quantified by using a dimensionless parameter, represented by the ratio of rainfall resolution (Lr) to the characteristic basin length (Lw), taken as the square root of the watershed area. Increasing the Lr/Lw parameter induces large errors on the simulated peak discharge, with values of the peak discharge error up to 0.33 for Lr/Lw equal to 1.0. An important error source related to spatial rainfall aggregation is the rainfall volume error caused by incorrectly smoothing the rainfall volume either inside or outside of of the watershed. It is found that for Lr/Lw 1.0, around 50% of the peak discharge error is due to the rainfall volume error. Remaining errors are due to both the distortion of the rainfall spatial distribution, measured with respect to the river network, and to the reduced spatial variability of the rainfield. Further investigations are required to isolate and examine the effect of river network geometry on the averaging of space-time rainfall at various aggregation lengths and on simulated peak discharges.
Investigation of long period crustal deformation on the inactive branch of the North Anatolian Fault Zone
Authors: Akay G. , Ozener H.
Published: April 2010

Abstract. The western part of North Anatolian Fault (NAF) bifurcates around Mudurnu into two fault segments: northern and southern branch. The latter bifurcates again at west of Pamukova and creates middle strand. This study aimed to analyze crustal movement along the middle strand near Iznik which is considered as inactive fault. We focused on a microgeodetic network called General Command of Mapping-Istanbul Technical University (GCM-ITU) network around this segment. In order to obtain displacement values, five campaigns performed on the network which were used in the study. The displacements of the stations were estimated relative to the fixed stations located at the south of the network. The coordinates of the stations were calculated from the triangulation measurements realized in 1941 and 1963, trilateration measurements in 1981, and GPS campaigns in 2004 and 2007. Then, mean displacements of the network ranging between 7 mm/yr and 18 mm/yr were obtained for these years. In the second part of the study, the GPS data were re-processed by adding three stations from Marmara Continuous GPS Network (MAGNET). Details of MAGNET can be found Ergintav et al. (2002). Estimated displacements were ranging between 3 mm/yr and 13 mm/yr for 2004 and 2007. TUBI station of IGS network was taken as stable.
Combined rock slope stability and shallow landslide susceptibility assessment of the Jasmund cliff area (Rügen Island, Germany)
Authors: Günther A. , Thiel C.
Published: April 2010

Abstract. In this contribution we evaluated both the structurally-controlled failure susceptibility of the fractured Cretaceous chalk rocks and the topographically-controlled shallow landslide susceptibility of the overlying glacial sediments for the Jasmund cliff area on Rügen Island, Germany. We employed a combined methodology involving spatially distributed kinematical rock slope failure testing with tectonic fabric data, and both physically- and inventory-based shallow landslide susceptibility analysis. The rock slope failure susceptibility model identifies areas of recent cliff collapses, confirming its value in predicting the locations of future failures. The model reveals that toppling is the most important failure type in the Cretaceous chalk rocks of the area. The shallow landslide susceptibility analysis involves a physically-based slope stability evaluation which utilizes material strength and hydraulic conductivity data, and a bivariate landslide susceptibility analysis exploiting landslide inventory data and thematic information on ground conditioning factors. Both models show reasonable success rates when evaluated with the available inventory data, and an attempt was made to combine the individual models to prepare a map displaying both terrain instability and landslide susceptibility. This combination highlights unstable cliff portions lacking discrete landslide areas as well as cliff sections highly affected by past landslide events. Through a spatial integration of the rock slope failure susceptibility model with the combined shallow landslide assessment we produced a comprehensive landslide susceptibility map for the Jasmund cliff area.
The tsunami geomorphology of coastal dunes
Authors: Goff J. R. , Lane E. , Arnold J.
Published: April 2010

Abstract. An examination of the coastal geomorphology of bays along the Otago coastline, SE New Zealand, has identified a geomorphology consistent with tsunami inundation. A tsunami geomorphology consisting of a number of elements including dune pedestals, hummocky topography, parabolic dune systems, and post-tsunami features resulting from changes to the nearshore sediment budget is discussed. The most prominent features at Blueskin Bay are eroded pedestals although it is speculated that hummocky topography may be present in the bay. Tsunami geomorphology at Long Beach is more comprehensive with a marked association between pedestals and a hummocky topography. A full suite of potential geomorphological features however, is not present at either site. The type of features formed by a tsunami, and the ability to detect and interpret a tsunami geomorphology, hinges on the interaction between five key variables; sand availability, embayment type, nature of the coast, accumulation space, and landward environmental conditions. An appreciation of the geomorphic setting and history of a coast is therefore of fundamental importance when identifying what to look for and where to look for tsunami evidence. It is also important to realise that these features can also be formed by other processes.
Developing capacity for natural hazard management using an active learning approach and web-based geographical information
Authors: Kos A.
Published: April 2010

Abstract. A learning environment for university students using active learning in the field of natural hazard management is described. Students study a suite of hazard case studies that include earthquake, flood, debris flow, rock fall, snow avalanche, and landslide within a virtual Alpine valley, which has been constructed using a web-based geographical information system. Through a series of tasks carried out in collaborative workshops, students create structure and meaning from heterogeneous and disparate data and information in order to define and solve relevant problems presented within a natural hazard scenario.
Characteristics of the extreme rainfall event and consequent flash floods in W Slovenia in September 2007
Authors: Rusjan S. , Kobold M. , Mikoš M.
Published: April 2010

Abstract. During a weather front that passed over large parts of Slovenia on 18.9.2007, extreme rainfall events were triggered causing several severe flash floods with six casualties. Out of 210 municipalities in Slovenia, 60 were reporting flood damages, and the total economic flood damage was later estimated at close to 200 million Euro; highest damage was claimed by Železniki municipality in NW Slovenia. The main purpose of the study presented in this paper was to put together available meteorological and hydrological data in order to get better insight into temporal and spatial dynamics and variability of the flash flood event along the Selška Sora River flowing through the town of Železniki. The weather forecast by the Environmental Agency of the Republic of Slovenia (ARSO) lead to early warning of floodings but has underestimated rainfall amounts by a factor of 2. Also meteorological radar underestimated ground rainfall as much as by 50%. During that day, in many rainfall gauging stations operated by ARSO in the area under investigation, extreme rainfall amounts were measured, e.g. 303 mm in 24 h or 157 mm in 2 h. Some of the measured rainfall amounts were the highest registered amounts in Slovenia so far. Statistical analysis using Gumble distribution was performed and rainfall return periods were estimated. When assessing rainfall return periods, a question of the sampling error as a consequence of short rainfall records used was raised. Furthermore, measured rainfall data were used to reconstruct hydrographs on selected water stations along the Selška Sora River. The cumulative areal precipitation for the Selška Sora River catchment upstream of Železniki amounted to 219 mm, while the modeled effective precipitation used to simulate the hydrograph peak was only 57 mm. The modeled direct runoff coefficient therefore amounts to 0.26. Surprisingly low value is mainly caused by the applied unit hydrograph method that seeks to meet the peak discharge rather than hydrograph volume. However, the spatial distribution of the rainfall in the area was highly variable and present spatial positioning of rain gauges is obviously inadequate for proper representation of the actual spatial amount of rainfall. The study confirmed that post-flood investigation should focus on discharges and hydrological response of the catchment rather than simply analyzing statistical characteristics of rainfall.
Chaos and magnetospheric dynamics
Authors: Pavlos G. P. , Diamandidis D. , Adamopoulos A. , Rigas A. G. , Daglis I. A. , Sarris E. T.
Published: April 2010

Abstract. Our intention in this work is to show, by using two different methods, that magnetospheric dynamics reveal low dimensional chaos. In the first method we extend the chaotic analysis for the AE index time series by including singular value decomposition (SVD) analysis in combination with Theiler's test in order to discriminate dynamical chaos from self-affinity or "crinkliness". The estimated fractality of the AE index time series which is obtained belongs to a strange attractor structure with close returns in the reconstructed phase space. In the second method we extend the linear equivalent magnetospheric electric circuit to a nonlinear one, the arithmetic solution of which reveals low dimensional chaotic dynamics. Both methods strongly support the existence of low dimensional magnetospheric chaos.
Monofractal or multifractal: a case study of spatial distribution of mining-induced seismic activity
Authors: Eneva M.
Published: April 2010

Abstract. Using finite data sets and limited size of study volumes may result in significant spurious effects when estimating the scaling properties of various physical processes. These effects are examined with an example featuring the spatial distribution of induced seismic activity in Creighton Mine (northern Ontario, Canada). The events studied in the present work occurred during a three-month period, March-May 1992, within a volume of approximate size 400 x 400 x 180 m3. Two sets of microearthquake locations are studied: Data Set 1 (14,338 events) and Data Set 2 (1654 events). Data Set 1 includes the more accurately located events and amounts to about 30 per cent of all recorded data. Data Set 2 represents a portion of the first data set that is formed by the most accurately located and the strongest microearthquakes. The spatial distribution of events in the two data sets is examined for scaling behaviour using the method of generalized correlation integrals featuring various moments q. From these, generalized correlation dimensions are estimated using the slope method. Similar estimates are made for randomly generated point sets using the same numbers of events and the same study volumes as for the real data. Uniform and monofractal random distributions are used for these simulations. In addition, samples from the real data are randomly extracted and the dimension spectra for these are examined as well. The spectra for the uniform and monofractal random generations show spurious multifractality due only to the use of finite numbers of data points and limited size of study volume. Comparing these with the spectra of dimensions for Data Set 1 and Data Set 2 allows us to estimate the bias likely to be present in the estimates for the real data. The strong multifractality suggested by the spectrum for Data Set 2 appears to be largely spurious; the spatial distribution, while different from uniform, could originate from a monofractal process. The spatial distribution of microearthquakes in Data Set 1 is either monofractal as well, or only weakly multifractal. In all similar studies, comparisons of result from real data and simulated point sets may help distinguish between genuine and artificial multifractality, without necessarily resorting to large number of data.
Nonlinear dynamics of wind waves: multifractal phase/time effects
Authors: Mellen R. H. , Leykin I. A.
Published: April 2010

Abstract. In addition to the bispectral coherence method, phase/time analysis of analytic signals is another promising avenue for the investigation of phase effects in wind waves. Frequency spectra of phase fluctuations obtained from both sea and laboratory experiments follow an F-β power law over several decades, suggesting that a fractal description is appropriate. However, many similar natural phenomena have been shown to be multifractal. Universal multifractals are quantified by two additional parameters: the Lévy index 0 < α < 2 for the type of multifractal and the co-dimension 0 < C1 < 1 for intermittence. The three parameters are a full statistical measure the nonlinear dynamics. Analysis of laboratory flume data is reported here and the results indicate that the phase fluctuations are 'hard multifractal' (α > 1). The actual estimate is close to the limiting value α = 2,  which is consistent with Kolmogorov's lognormal model for turbulent fluctuations. Implications for radar and sonar backscattering from the sea surface are briefly considered.