http://www.nat-hazards-earth-syst-sci.net/Natural Hazards and Earth System Science Latest Articleshttp://www.nat-hazards-earth-syst-sci.net/10/1807/2010/<b>Monitoring subsidence effects in the urban area of Zonguldak Hardcoal Basin of Turkey by InSAR-GIS integration</b><br /><br />Natural Hazards and Earth System Science, 10, 1807-1814, 2010<br /><br />Author(s): H. Akcin, H. S. Kutoglu, H. Kemaldere, T. Deguchi, and E. Koksal<br /><br />Zonguldak Hardcoal Basin is the largest bituminous coal region in Turkey where extensive underground mining activity exists. Because of this activity subsidence effects have been experienced in different locations of the city. In this study, surface deformations caused by the subsidence have been observed by D-InSAR technique using C-Band RADARSAT data. InSAR data process of 16 RADARSAT images acquired between 24 July 2005–23 October 2006 has resulted in significant deformations in the order of about 6 cm in the most populated region of the city. The deformation map obtained has been integrated with digitized mine production maps and Quickbird Orthoimage into GIS. According to GIS analysis, there are three mine seams at different levels driven below the deformed zone. Many governmental and private buildings located in this area have a high potential risk of subsidence damage. Also, this area covers approximately 12 km of transportation routes.2010-09-01T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1793/2010/<b>Written records of historical tsunamis in the northeastern South China Sea – challenges associated with developing a new integrated database</b><br /><br />Natural Hazards and Earth System Science, 10, 1793-1806, 2010<br /><br />Author(s): A. Y. A. Lau, A. D. Switzer, D. Dominey-Howes, J. C. Aitchison, and Y. Zong<br /><br />Comprehensive analysis of 15 previously published regional databases incorporating more than 100 sources leads to a newly revised historical tsunami database for the northeastern (NE) region of the South China Sea (SCS) including Taiwan. The validity of each reported historical tsunami event listed in our database is assessed by comparing and contrasting the information and descriptions provided in the other databases. All earlier databases suffer from errors associated with inaccuracies in translation between different languages, calendars and location names. The new database contains 205 records of "events" reported to have occurred between AD 1076 and 2009. We identify and investigate 58 recorded tsunami events in the region. The validity of each event is based on the consistency and accuracy of the reports along with the relative number of individual records for that event. Of the 58 events, 23 are regarded as "valid" (confirmed) events, three are "probable" events and six are "possible". Eighteen events are considered "doubtful" and eight events "invalid". The most destructive tsunami of the 23 valid events occurred in 1867 and affected Keelung, northern Taiwan, killing at least 100 people. Inaccuracies in the historical record aside, this new database highlights the occurrence and geographical extent of several large tsunamis in the NE SCS region and allows an elementary statistical analysis of annual recurrence intervals. Based on historical records from 1951–2009 the probability of a tsunami (from any source) affecting the region in any given year is relatively high (33.4%). However, the likelihood of a tsunami that has a wave height >1 m, and/or causes fatalities and damage to infrastructure occurring in the region in any given year is low (1–2%). This work indicates the need for further research using coastal stratigraphy and inundation modeling to help validate some of the historical accounts of tsunamis as well as adequately evaluate the recurrence intervals of tsunamis along the now heavily developed coastlines of the region.2010-09-01T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1781/2010/<b>Parametric studies and quantitative assessment of the vulnerability of a RC frame building exposed to differential settlements</b><br /><br />Natural Hazards and Earth System Science, 10, 1781-1792, 2010<br /><br />Author(s): C. Negulescu and E. Foerster<br /><br />The aim of this paper is to propose a simplified methodology to evaluate the mechanical performances of buildings exposed to landslide hazard, by using procedures inspired from the seismic risk analysis, such as the Capacity Spectrum Method (ATC 40, 1996). Landslide hazard involves so many aspects, that quantitative vulnerability assessment requires to consider one basic scenario at a time, i.e. one typology for the landslide hazard and one for the structural element considered. In this paper, we propose to assess vulnerability for simple one bay-one storey reinforced concrete (RC) frame structures subjected to differential settlements, using 2-D parametric nonlinear static time-history analyses. After a short review of methods used in practice to estimate building deformations induced by ground movements (e.g. differential settlements), we present the parametric studies carried out to identify the most relevant parameters, in order to predict the structural damage, as well as the methodology to develop analytical fragility curves, that can be used to quantitatively evaluate the structural vulnerability in landslide risk analyses. Different types of parameters that could influence structural behaviour have been examined in this analysis: foundation type (i.e. different combinations of links), cross-section geometry, section reinforcement degree, displacement magnitudes and displacement inclination angles. We show that the magnitude and inclination angle of displacements can be used as two relevant parameters for this type of landslide scenario. Based on these results, some simulations are conducted using the software SeismoStruct (SeismoSoft, 2003), and the proposed structural damage levels consider the local strain limits of steel and concrete constitutive materials. Some preliminary fragility curves are proposed with respect to the magnitude of differential ground displacement. It can be seen that the curves corresponding to limit states LS2 (moderate damage) and LS4 (complete damage) in the present study, correspond respectively to the "tolerable settlements" "observed intolerable settlements" curves proposed by Zhang and Ng (2005).2010-09-01T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1759/2010/<b>The GITEWS ocean bottom sensor packages</b><br /><br />Natural Hazards and Earth System Science, 10, 1759-1780, 2010<br /><br />Author(s): O. Boebel, M. Busack, E. R. Flueh, V. Gouretski, H. Rohr, A. Macrander, A. Krabbenhoeft, M. Motz, and T. Radtke<br /><br />The German-Indonesian Tsunami Early Warning System (GITEWS) aims at reducing the risks posed by events such as the 26 December 2004 Indian Ocean tsunami. To minimize the lead time for tsunami alerts, to avoid false alarms, and to accurately predict tsunami wave heights, real-time observations of ocean bottom pressure from the deep ocean are required. As part of the GITEWS infrastructure, the parallel development of two ocean bottom sensor packages, PACT (Pressure based Acoustically Coupled Tsunameter) and OBU (Ocean Bottom Unit), was initiated. The sensor package requirements included bidirectional acoustic links between the bottom sensor packages and the hosting surface buoys, which are moored nearby. Furthermore, compatibility between these sensor systems and the overall GITEWS data-flow structure and command hierarchy was mandatory. While PACT aims at providing highly reliable, long term bottom pressure data only, OBU is based on ocean bottom seismometers to concurrently record sea-floor motion, necessitating highest data rates. This paper presents the technical design of PACT, OBU and the HydroAcoustic Modem (HAM.node) which is used by both systems, along with first results from instrument deployments off Indonesia.2010-08-31T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1751/2010/<b>Ionospheric anomaly due to seismic activities – Part 2: Evidence from D-layer preparation and disappearance times</b><br /><br />Natural Hazards and Earth System Science, 10, 1751-1757, 2010<br /><br />Author(s): S. K. Chakrabarti, S. Sasmal, and S. Chakrabarti<br /><br />We show evidences for anomalous ionospheric behaviour in the signal of Indian navy VLF transmitting station named VTX due to earthquakes in the South Asian region. We concentrate on the variation of the D-layer preparation time (DLPT) and D-layer disappearance time (DLDT) in a period of sixteen months and study their average behaviors. We identify those days in which DLPT and DLDT exhibit significant deviations. Separately, we compute the energy release by earthquakes during this period and show that "anomalous VLF" days are associated with anomalous energy release. We find that the anomaly and the deviation of DLPT and DLDTs from the mean are linearly correlated. We discuss the predictability in this approach and compare with the terminator shift approach using the same set of data.2010-08-25T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1739/2010/<b>Public assessment of the usefulness of "draft" tsunami evacuation maps from Sydney, Australia – implications for the establishment of formal evacuation plans</b><br /><br />Natural Hazards and Earth System Science, 10, 1739-1750, 2010<br /><br />Author(s): F. Dall'Osso and D. Dominey-Howes<br /><br />Australia is at risk from tsunamis and recent work has identified the need for models to assess the vulnerability of exposed coastal areas – a fundamental element of the risk management process. Outputs of vulnerability assessment can be used as a baseline for the generation of tsunami prevention and mitigation measures, including evacuation maps. Having noted that no evacuation maps exist for Manly, Sydney (an area recently subjected to high resolution building vulnerability assessment by Dall'Osso et al., 2009b), we use the results of the analysis by Dall'Osso et al. (2009b) to "draft" tsunami evacuation maps that could be used by the local emergency service organisations. We then interviewed 500 permanent residents of Manly in order to gain a rapid assessment on their views about the potential usefulness of the draft evacuation maps we generated. Results of the survey indicate that residents think the maps are useful and understandable, and include insights that should be considered by local government planners and emergency risk management specialists during the development of official evacuation maps (and plans) in the future.2010-08-25T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1725/2010/<b>Climate change and its effect on agriculture, water resources and human health sectors in Poland</b><br /><br />Natural Hazards and Earth System Science, 10, 1725-1737, 2010<br /><br />Author(s): M. Szwed, G. Karg, I. Pińskwar, M. Radziejewski, D. Graczyk, A. Kędziora, and Z. W. Kundzewicz<br /><br />Multi-model ensemble climate projections in the ENSEMBLES Project of the EU allowed the authors to quantify selected extreme-weather indices for Poland, of importance to climate impacts on systems and sectors. Among indices were: number of days in a year with high value of the heat index; with high maximum and minimum temperatures; length of vegetation period; and number of consecutive dry days. Agricultural, hydrological, and human health indices were applied to evaluate the changing risk of weather extremes in Poland in three sectors. To achieve this, model-based simulations were compared for two time horizons, a century apart, i.e., 1961–1990 and 2061–2090. Climate changes, and in particular increases in temperature and changes in rainfall, have strong impacts on agriculture via weather extremes – droughts and heat waves. The crop yield depends particularly on water availability in the plant development phase. To estimate the changes in present and future yield of two crops important for Polish agriculture i.e., potatoes and wheat, some simple empirical models were used. For these crops, decrease of yield is projected for most of the country, with national means of yield change being: –2.175 t/ha for potatoes and –0.539 t/ha for wheat. Already now, in most of Poland, evapotranspiration exceeds precipitation during summer, hence the water storage (in surface water bodies, soil and ground) decreases. Summer precipitation deficit is projected to increase considerably in the future. The additional water supplies (above precipitation) needed to use the agro-potential of the environment would increase by half. Analysis of water balance components (now and in the projected future) can corroborate such conclusions. As regards climate and health, a composite index, proposed in this paper, is a product of the number of senior discomfort days and the number of seniors (aged 65+). The value of this index is projected to increase over 8-fold during 100 years. This is an effect of both increase in the number of seniors (over twofold) and the number of senior-discomfort days (nearly fourfold).2010-08-19T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1697/2010/<b>Review article "Assessment of economic flood damage"</b><br /><br />Natural Hazards and Earth System Science, 10, 1697-1724, 2010<br /><br />Author(s): B. Merz, H. Kreibich, R. Schwarze, and A. Thieken<br /><br />Damage assessments of natural hazards supply crucial information to decision support and policy development in the fields of natural hazard management and adaptation planning to climate change. Specifically, the estimation of economic flood damage is gaining greater importance as flood risk management is becoming the dominant approach of flood control policies throughout Europe. This paper reviews the state-of-the-art and identifies research directions of economic flood damage assessment. Despite the fact that considerable research effort has been spent and progress has been made on damage data collection, data analysis and model development in recent years, there still seems to be a mismatch between the relevance of damage assessments and the quality of the available models and datasets. Often, simple approaches are used, mainly due to limitations in available data and knowledge on damage mechanisms. The results of damage assessments depend on many assumptions, e.g. the selection of spatial and temporal boundaries, and there are many pitfalls in economic evaluation, e.g. the choice between replacement costs or depreciated values. Much larger efforts are required for empirical and synthetic data collection and for providing consistent, reliable data to scientists and practitioners. A major shortcoming of damage modelling is that model validation is scarcely performed. Uncertainty analyses and thorough scrutiny of model inputs and assumptions should be mandatory for each damage model development and application, respectively. In our view, flood risk assessments are often not well balanced. Much more attention is given to the hazard assessment part, whereas damage assessment is treated as some kind of appendix within the risk analysis. Advances in flood damage assessment could trigger subsequent methodological improvements in other natural hazard areas with comparable time-space properties.2010-08-18T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1689/2010/<b>On the application of kinematic models to simulate the diffusive processes of debris flows</b><br /><br />Natural Hazards and Earth System Science, 10, 1689-1695, 2010<br /><br />Author(s): M. Arattano and L. Franzi<br /><br />Debris flows generally propagate along steep mountain torrents with dynamics primarily governed by gravitational and frictional forces. Thus, debris flows modelling can be successfully performed through the application of kinematic models, which consider only the effects of slope and friction and neglect the remaining terms of the momentum equation. However, the diffusion processes that can be observed in the field, such as the spreading of the debris flow wave as it flows downstream, can not be theoretically predicted by kinematic models, since diffusion is a second-order process neglected in the kinematic approximation. In this paper, this issue is discussed and an application for both a generalized diffusion wave model and a kinematic model is proposed of a debris flow which occurred in an Italian instrumented torrent to identify, in a real case scenario, the effective value of the neglected terms in the kinematic approximation.2010-08-18T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1679/2010/<b>Tsunami inundation modelling based on detailed roughness maps of densely populated areas</b><br /><br />Natural Hazards and Earth System Science, 10, 1679-1687, 2010<br /><br />Author(s): G. Gayer, S. Leschka, I. Nöhren, O. Larsen, and H. Günther<br /><br />An important part within the German-Indonesian Tsunami Early Warning System (GITEWS) project was the detailed numerical investigation of the impact of tsunamis in densely populated coastal areas of Indonesia. This work, carried out by the German Research Centre Geesthacht (GKSS), in co-operation with DHI-WASY, also provides the basis for the preparation of high resolution hazard and risk maps by the German Aerospace Center (DLR). <br><br> In this paper a method is described of how to prepare very detailed roughness maps for scenario computations performed with the MIKE 21 Flow Model FM in three highly resolved (~10 m) priority regions, namely Kuta (Bali), Padang (West-Sumatra), and Cilacap (southern coast of Java). Roughness values are assigned to 43 land use classes, e.g. different types of buildings, rural and urban sub-areas, by using equivalent coefficients found in literature or by performing numerical experiments. <br><br> Comparisons of simulations using differentiated roughness maps with simulations using constant values (a widely used approach) are presented and it is demonstrated that roughness takes considerable influence on run-up and inundation. <br><br> Out of all simulations, the results of the worst case scenarios for each of the three priority areas are discussed. Earthquakes with magnitudes of <i>M</i>_W=8.5 or higher lead to considerable inundation in all study sites. A spatially distinguished consideration of roughness has been found to be necessary for detailed modelling onshore.2010-08-03T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1663/2010/<b>The social psychology of seismic hazard adjustment: re-evaluating the international literature</b><br /><br />Natural Hazards and Earth System Science, 10, 1663-1677, 2010<br /><br />Author(s): C. Solberg, T. Rossetto, and H. Joffe<br /><br />The majority of people at risk from earthquakes do little or nothing to reduce their vulnerability. Over the past 40 years social scientists have tried to predict and explain levels of seismic hazard adjustment using models from behavioural sciences such as psychology. The present paper is the first to synthesise the major findings from the international literature on psychological correlates and causes of seismic adjustment at the level of the individual and the household. It starts by reviewing research on seismic risk perception. Next, it looks at norms and normative beliefs, focusing particularly on issues of earthquake protection responsibility and trust between risk stakeholders. It then considers research on attitudes towards seismic adjustment attributes, specifically beliefs about efficacy, control and fate. It concludes that an updated model of seismic adjustment must give the issues of norms, trust, power and identity a more prominent role. These have been only sparsely represented in the social psychological literature to date.2010-08-03T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1647/2010/<b>Climate change assessment for Mediterranean agricultural areas by statistical downscaling</b><br /><br />Natural Hazards and Earth System Science, 10, 1647-1661, 2010<br /><br />Author(s): L. Palatella, M. M. Miglietta, P. Paradisi, and P. Lionello<br /><br />In this paper we produce projections of seasonal precipitation for four Mediterranean areas: Apulia region (Italy), Ebro river basin (Spain), Po valley (Italy) and Antalya province (Turkey). We performed the statistical downscaling using Canonical Correlation Analysis (CCA) in two versions: in one case Principal Component Analysis (PCA) filter is applied only to predictor and in the other to both predictor and predictand. After performing a validation test, CCA after PCA filter on both predictor and predictand has been chosen. Sea level pressure (SLP) is used as predictor. Downscaling has been carried out for the scenarios A2 and B2 on the basis of three GCM's: the CCCma-GCM2, the Csiro-MK2 and HadCM3. Three consecutive 30-year periods have been considered. For Summer precipitation in Apulia region we also use the 500 hPa temperature (T500) as predictor, obtaining comparable results. Results show different climate change signals in the four areas and confirm the need of an analysis that is capable of resolving internal differences within the Mediterranean region. The most robust signal is the reduction of Summer precipitation in the Ebro river basin. Other significative results are the increase of precipitation over Apulia in Summer, the reduction over the Po-valley in Spring and Autumn and the increase over the Antalya province in Summer and Autumn.2010-07-30T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1635/2010/<b>Description and analysis of the debris flows occurred during 2008 in the Eastern Pyrenees</b><br /><br />Natural Hazards and Earth System Science, 10, 1635-1645, 2010<br /><br />Author(s): M. Portilla, G. Chevalier, and M. Hürlimann<br /><br />Rainfall-triggered landslides taking place in the Spanish Eastern Pyrenees have usually been analysed on a regional scale. Most research focussed either on terrain susceptibility or on the characteristics of the critical rainfall, neglecting a detailed analysis of individual events. In contrast to other mountainous regions, research on debris flow has only been performed marginally and associated hazard has mostly been neglected. <br><br> In this study, five debris flows, which occurred in 2008, are selected; and site specific descriptions and analysis regarding geology, morphology, rainfall data and runout were performed. The results are compared with worldwide data and some conclusions on hazard assessment are presented. <br><br> The five events can be divided into two in-channel debris flows and three landslide-triggered debris flows. The in-channel generated debris flows exceeded 10 000 m³, which are unusually large mass movements compared to historic events which occurred in the Eastern Pyrenees. In contrast, the other events mobilised total volumes less than 2000 m³. The geomorphologic analysis showed that the studied events emphasize similar patterns when compared to published data focussing on slope angle in the initiation zone or catchment area. <br><br> Rainfall data revealed that all debris flows were triggered by high intensity-short duration rainstorms during the summer season. Unfortunately, existing rainfall thresholds in the Eastern Pyrenees consider long-lasting rainfall, usually occurring in autumn/winter. Therefore, new thresholds should be established taking into account the rainfall peak intensity in mm/h, which seems to be a much more relevant factor for summer than the event's total precipitation. <br><br> The runout analysis of the 2008 debris flows confirms the trend that larger volumes generally induce higher mobility. The numerical simulation of the Riu Runer event shows that its dynamic behaviour is well represented by Voellmy fluid rheology. A maximum front velocity of 7 m/s was back-analysed for the transit section and even on the fan velocities larger than 2 m/s were obtained. <br><br> This preliminary analysis of the major Eastern Pyrenean debris flows represents the first background for future studies. Additional research on other events is necessary to support the results presented herein, and to properly assess and reduce hazard related to debris flows.2010-07-30T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1629/2010/<b>Connection of large earthquakes occurring moment with the movement of the Sun and the Moon and with the Earth crust tectonic stress character</b><br /><br />Natural Hazards and Earth System Science, 10, 1629-1633, 2010<br /><br />Author(s): M. K. Kachakhidze, R. Kiladze, N. Kachakhidze, V. Kukhianidze, and G. Ramishvili<br /><br />It is acceptable that earthquakes certain exogenous (cosmic) triggering factors may exist in every seismoactive (s/a) region and in Caucasus among them. They have to correct earthquake occurring moment or play the triggering role in case when the region is at the limit of the critical value of the geological medium of course. <br><br> Our aim is to reveal some exogenous factors possible to initiate earthquakes, on example of Caucasus s/a region, taking into account that the region is very complex by the point of view of the tectonic stress distribution. <br><br> The compression stress directed from North to South (and vice versa) and the spread stress directed from East to West (and vice versa) are the main stresses acted in Caucasus region. No doubt that action of the smallest external stress may "work" as earthquakes triggering factor. <br><br> In the presented work the Moon and the Sun perturbations are revealed as initiative agents of earthquakes when the directions of corresponding exogenous forces coincide with the directions of the compression stress or the spreading tectonic stress in the region.2010-07-29T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1617/2010/<b>Source modeling and inversion with near real-time GPS: a GITEWS perspective for Indonesia</b><br /><br />Natural Hazards and Earth System Science, 10, 1617-1627, 2010<br /><br />Author(s): A. Y. Babeyko, A. Hoechner, and S. V. Sobolev<br /><br />We present the GITEWS approach to source modeling for the tsunami early warning in Indonesia. Near-field tsunami implies special requirements to both warning time and details of source characterization. To meet these requirements, we employ geophysical and geological information to predefine a maximum number of rupture parameters. We discretize the tsunamigenic Sunda plate interface into an ordered grid of patches (150&times;25) and employ the concept of Green's functions for forward and inverse rupture modeling. Rupture Generator, a forward modeling tool, additionally employs different scaling laws and slip shape functions to construct physically reasonable source models using basic seismic information only (magnitude and epicenter location). GITEWS runs a library of semi- and fully-synthetic scenarios to be extensively employed by system testing as well as by warning center personnel teaching and training. Near real-time GPS observations are a very valuable complement to the local tsunami warning system. Their inversion provides quick (within a few minutes on an event) estimation of the earthquake magnitude, rupture position and, in case of sufficient station coverage, details of slip distribution.2010-07-26T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1605/2010/<b>Physical controls on the scale-dependence of ensemble streamflow forecast dispersion</b><br /><br />Natural Hazards and Earth System Science, 10, 1605-1615, 2010<br /><br />Author(s): G. Mascaro, E. R. Vivoni, and R. Deidda<br /><br />The accuracy of ensemble streamflow forecasts (ESFs) is impacted by the propagation of uncertainty associated with quantitative precipitation forecasts (QPFs) through the physical processes occurring in the basin. In this study, we consider consistent ESFs (i.e., observations and ensemble members are equally likely) and we study the effect of basin area (<i>A</i>) and antecedent rainfall (AR) on the ESF dispersion, a metric of flood forecast skill. Results from a set of numerical experiments indicate that: (i) for small basins (&#x2272;180 km²), ESF dispersion is mainly dominated by the runoff generation process and does not depend on the basin size <i>A</i>; (ii) for larger areas, ESF dispersion decreases with <i>A</i> according to a log-linear relation due to the decreasing variability of ensemble QPFs and, possibly, to the channel routing process. In addition, we found that, regardless the basin size, the ESF dispersion decreases as AR increases, and that the influence of AR is larger for basins with fast response times. Physical controls (land cover, soil texture and morphometric features) on the analyzed basin response confirm these interpretations.2010-07-23T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1591/2010/<b>The efficiency of a risk reduction program for debris-flow disasters – a case study of the Songhe community in Taiwan</b><br /><br />Natural Hazards and Earth System Science, 10, 1591-1603, 2010<br /><br />Author(s): S. C. Chen, C. Y. Wu, and B. T. Huang<br /><br />A risk reduction program was developed after debris-flow disaster analysis is conducted using mitigation structures, evacuation measures and community restrained expansion strategy. The risk assessment method delineates hazard zones and analyzes vulnerability and the resilient capacity of an affected area, allowing the prediction of losses of properties and lives, and the corresponding risk. It can also be used to evaluate performance of a risk reduction program. The proposed method was applied to the Songhe community as a case study to assess debris-flow risk and performance of reduction programs consisting of mitigation structures, evacuation measures and a restrained expansion strategy. Total annual risk decreased to $0.01 million from $0.72 million for the No. 1 Torrent and to $0.36 million from $1.22 million for the No. 2 Torrent after mitigation structures were installed, and evacuation measures were implemented based on restrained expansion. Although mitigation structures are costly, they can reduce the size of hazard zones. Delimitating the Designated Soil and Water Conservation Area restrains community expansion and decreases possible losses. Although evacuation measures cannot reduce the size of hazard zones, they effectively increase the resilient capacity of residents. The benefit-cost ratio for mitigation structures exceeds 1.0 for both torrents with an average of 3.87; the benefit-cost ratio for evacuation measures is markedly greater than 1.0. Combining mitigation structures and evacuation measures increases the total benefit with a benefit-cost ratio of 4.38. Analytical results showed that the risk reduction program is cost-effective.2010-07-16T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1575/2010/<b>A model for assessing the systemic vulnerability in landslide prone areas</b><br /><br />Natural Hazards and Earth System Science, 10, 1575-1590, 2010<br /><br />Author(s): S. Pascale, F. Sdao, and A. Sole<br /><br />The objectives of spatial planning should include the definition and assessment of possible mitigation strategies regarding the effects of natural hazards on the surrounding territory. Unfortunately, however, there is often a lack of adequate tools to provide necessary support to the local bodies responsible for land management. This paper deals with the conception, the development and the validation of an integrated numerical model for assessing systemic vulnerability in complex and urbanized landslide-prone areas. The proposed model considers this vulnerability not as a characteristic of a particular element at risk, but as a peculiarity of a complex territorial system, in which the elements are reciprocally linked in a functional way. It is an index of the tendency of a given territorial element to suffer damage (usually of a functional kind) due to its interconnections with other elements of the same territorial system. The innovative nature of this work also lies in the formalization of a procedure based on a network of influences for an adequate assessment of such "systemic" vulnerability. <br><br> This approach can be used to obtain information which is useful, in any given situation of a territory hit by a landslide event, for the identification of the element which has suffered the most functional damage, ie the most "critical" element and the element which has the greatest repercussions on other elements of the system and thus a "decisive" role in the management of the emergency. <br><br> This model was developed within a GIS system through the following phases: <br><br> 1. the topological characterization of the territorial system studied and the assessment of the scenarios in terms of spatial landslide hazard. A statistical method, based on neural networks was proposed for the assessment of landslide hazard; <br><br> 2. the analysis of the direct consequences of a scenario event on the system; <br><br> 3. the definition of the assessment model of systemic vulnerability in landslide-prone areas. <br><br> To highlight the potentialities of the proposed approach we have described a specific case study of landslide hazard in the local council area of Potenza.2010-07-16T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1563/2010/<b>Growing season precipitation in Finland under recent and projected climate</b><br /><br />Natural Hazards and Earth System Science, 10, 1563-1574, 2010<br /><br />Author(s): J. S. Ylhäisi, H. Tietäväinen,, P. Peltonen-Sainio, A. Venäläinen, J. Eklund, J. Räisänen, and K. Jylhä<br /><br />The past and projected future precipitation sum in May–September for two areas in Finland, one located in the south-west (SW) and the other in the north-east (NE), is studied using 13 regional climate simulations and three observational datasets. The conditions in the present-day climate for agricultural crop production are far more favourable in the south-western part of the country than the more continental north-eastern Finland. Based on a new high-resolution observational precipitation dataset for Finland (<i>FMI_grid</i>), with a resolution of 10&times;10 km, the only statistically significant past long-term (1908–2008) precipitation tendencies in the two study regions are positive. Differences between <i>FMI_grid</i> and two other observational datasets during 1961–2000 are rather large in the NE, whereas in the SW the datasets agree better. Observational uncertainties stem from the interpolation and sampling errors. The projected increases in precipitation in the early stage of the growing season would be most favourable for agricultural productivity, but the projected increases in August and September might be harmful. Model projections for the future indicate a statistically significant increase in precipitation for most of the growing season by 2100, but the distribution of precipitation within the growing season is not necessarily the most optimal.2010-07-16T00:00:00+02:00http://www.nat-hazards-earth-syst-sci.net/10/1547/2010/<b>Applying and validating the PTVA-3 Model at the Aeolian Islands, Italy: assessment of the vulnerability of buildings to tsunamis</b><br /><br />Natural Hazards and Earth System Science, 10, 1547-1562, 2010<br /><br />Author(s): F. Dall'Osso, A. Maramai, L. Graziani, B. Brizuela, A. Cavalletti, M. Gonella, and S. Tinti<br /><br />The volcanic archipelago of the Aeolian Islands (Sicily, Italy) is included on the UNESCO World Heritage list and is visited by more than 200 000 tourists per year. Due to its geological characteristics, the risk related to volcanic and seismic activity is particularly high. Since 1916 the archipelago has been hit by eight local tsunamis. The most recent and intense of these events happened on 30 December 2002. It was triggered by two successive landslides along the north-western side of the Stromboli volcano (Sciara del Fuoco), which poured approximately 2–3&times;10⁷ m³ of rocks and debris into the Tyrrhenian Sea. The waves impacted across the whole archipelago, but most of the damage to buildings and infrastructures occurred on the islands of Stromboli (maximum run-up 11 m) and Panarea. <br><br> The aim of this study is to assess the vulnerability of buildings to damage from tsunamis located within the same area inundated by the 2002 event. The assessment is carried out by using the PTVA-3 Model (Papathoma Tsunami Vulnerability Assessment, version 3). The PTVA-3 Model calculates a Relative Vulnerability Index (RVI) for every building, based on a set of selected physical and structural attributes. Run-up values within the area inundated by the 2002 tsunami were measured and mapped by the Istituto Italiano di Geofisica e Vulcanologia (INGV) and the University of Bologna during field surveys in January 2003. Results of the assessment show that if the same tsunami were to occur today, 54 buildings would be affected in Stromboli, and 5 in Panarea. The overall vulnerability level obtained in this analysis for Stromboli and Panarea are "average"/"low" and "very low", respectively. Nonetheless, 14 buildings in Stromboli are classified as having a "high" or "average" vulnerability. For some buildings, we were able to validate the RVI scores calculated by the PTVA-3 Model through a qualitative comparison with photographs taken by INGV and the University of Bologna during the post-tsunami survey. With the exception of a single structure, which is partially covered by a coastal dune on the seaward side, we found a good degree of accuracy between the PTVA-3 Model forecast assessments and the actual degree of damage experienced by buildings. This validation of the model increases our confidence in its predictive capability. Given the high tsunami risk for the archipelago, our results provide a framework for prioritising investments in prevention measures and addressing the most relevant vulnerability issues of the built environment, particularly on the island of Stromboli.2010-07-15T00:00:00+02:00