ALBERT

Description: Intercomparison of two meteorological limited area models for quantitative precipitation forecast verification Natural Hazards and Earth System Science, 12, 591-606, 2012 Author(s): E. Oberto, M. Milelli, F. Pasi, and B. Gozzini The demand for verification of numerical models is still very high, especially for what concerns the operational Quantitative Precipitation Forecast (QPF) used, among others, for evaluating the issuing of warnings to the population. In this study, a comparative verification of the QPF, predicted by two operational Limited Area Models (LAMs) for the Italian territory is presented: COSMO-I7 (developed in the framework of the COSMO Consortium) and WRF-NMM (developed at NOAA-NCEP). The observational dataset is the precipitation recorded by the high-resolution non-GTS rain gauges network of the National Civil Protection Department (NCPD) over two years (2007–2008). Observed and forecasted precipitation have been treated as areal quantity (areal average of the values accumulated in 6 and 24 h periods) over the 102 "warning areas", defined by the NCPD both for administrative and hydrological purposes. Statistics are presented through a series of conventional indices (BIAS, POD and POFD) and, in addition, the Extreme Dependency Score (EDS) and the Base Rate (BS or 1-BS) have been used for keeping into account the vanishing of the indices as the events become rare. Results for long-period verification (the whole 2 yr) with increasing thresholds, seasonal trend (3 months period), diurnal error cycle and error maps, are presented. Results indicate that WRF has a general tendency of QPF overestimation for low thresholds and underestimation for higher ones, while COSMO-I7 tends to overestimate for all thresholds. Both models show a seasonal trend, with a bigger overestimation during summer and spring, while during autumn and winter the models tend to be more accurate.

Description: Rockfall hazard and risk assessments along roads at a regional scale: example in Swiss Alps Natural Hazards and Earth System Science, 12, 615-629, 2012 Author(s): C. Michoud, M.-H. Derron, P. Horton, M. Jaboyedoff, F.-J. Baillifard, A. Loye, P. Nicolet, A. Pedrazzini, and A. Queyrel Unlike fragmental rockfall runout assessments, there are only few robust methods to quantify rock-mass-failure susceptibilities at regional scale. A detailed slope angle analysis of recent Digital Elevation Models (DEM) can be used to detect potential rockfall source areas, thanks to the Slope Angle Distribution procedure. However, this method does not provide any information on block-release frequencies inside identified areas. The present paper adds to the Slope Angle Distribution of cliffs unit its normalized cumulative distribution function. This improvement is assimilated to a quantitative weighting of slope angles, introducing rock-mass-failure susceptibilities inside rockfall source areas previously detected. Then rockfall runout assessment is performed using the GIS- and process-based software Flow-R, providing relative frequencies for runout. Thus, taking into consideration both susceptibility results, this approach can be used to establish, after calibration, hazard and risk maps at regional scale. As an example, a risk analysis of vehicle traffic exposed to rockfalls is performed along the main roads of the Swiss alpine valley of Bagnes.

Description: Evolution of skewness and kurtosis of weakly nonlinear unidirectional waves over a sloping bottom Natural Hazards and Earth System Science, 12, 631-638, 2012 Author(s): H. Zeng and K. Trulsen We consider the effect of slowly varying depth on the values of skewness and kurtosis of weakly nonlinear irregular waves propagating from deeper to shallower water. It is known that the equilibrium value of kurtosis decreases with decreasing depth for waves propagating on constant depth. Waves propagating over a sloping bottom must continually adjust toward a new equilibrium state. We demonstrate that weakly nonlinear waves may need a considerable horizontal propagation distance in order to adjust to a new shallower environment, therefore the kurtosis can be notably different from the equilibrium value for each corresponding depth both on top of and beyond a bottom slope. A change of depth can provoke a wake-like spatially non-uniform distribution of kurtosis on the lee side of the slope. As an application, we anticipate that the probability of freak waves on or near the edge of the continental shelf may exhibit a rather complicated spatial structure for wave fields entering from deep sea.

Description: Corrigendum to "Impact of rainfall spatial distribution on rainfall-runoff modelling efficiency and initial soil moisture conditions estimation" published in Nat. Hazards Earth Syst. Sci., 11, 157–170, 2011 Natural Hazards and Earth System Science, 12, 267-267, 2012 Author(s): Y. Tramblay, C. Bouvier, P.-A. Ayral, and A. Marchandise No abstract available.

Description: Evolution of marine storminess in the Belgian part of the North Sea Natural Hazards and Earth System Science, 12, 305-312, 2012 Author(s): D. Van den Eynde, R. De Sutter, and P. Haerens Severe storms have affected European coast lines in the past but knowledge on changes in storminess for the last decades is still sparse. Climate change is assumed to be a main driving factor with the potential to induce changes on the intensity, duration and frequency of powerful marine storms, including a long-term influence on peak wind speeds, surges and waves. It is, therefore, important to investigate whether in the last decades changes in the magnitude of storms, their duration and frequency could be observed. Understanding trends in storminess in the last decades will help to better prepare coastal managers for future events, taking into account potential changes on storm occurrence and magnitude to improve planning of mitigation and adaptation strategies. The purpose of this study was to focus on the evolution of extreme wind conditions, wave height and storm surge levels in the North Sea Region, especially in the Belgian part of the North Sea (BPNS). Based on the analysis performed it is concluded that no clear trend can be observed for the occurrence of significant increasing extreme wind speeds over the BPNS. Furthermore, one can conclude that not enough scientific evidence is available to support scenarios with increased wave height or storminess.

Description: The 2007 flood in the Sahel: causes, characteristics and its presentation in the media and FEWS NET Natural Hazards and Earth System Science, 12, 313-325, 2012 Author(s): C. Samimi, A. H. Fink, and H. Paeth During the rainy season in 2007, reports about exceptional rains and floodings in the Sahel were published in the media, especially in August and September. Institutions and organizations like the World Food Programme (WFP) and FEWS NET put the events on the agenda and released alerts and requested help. The partly controversial picture was that most of the Sahel faced a crisis caused by widespread floodings. Our study shows that the rainy season in 2007 was exceptional with regard to rainfall amount and return periods. In many areas the event had a return period between 1 and 50 yr with high spatial heterogeneity, with the exception of the Upper Volta basin, which yielded return periods of up to 1200 yr. Despite the strong rainfall, the interpretation of satellite images show that the floods were mainly confined to lakes and river beds. However, the study also proves the difficulties in assessing the meteorological processes and the demarcation of flooded areas in satellite images without ground truthing. These facts and the somewhat vague and controversial reports in the media and FEWS NET demonstrate that it is crucial to thoroughly analyze such events at a regional and local scale involving the local population.

Description: Factors selection in landslide susceptibility modelling on large scale following the gis matrix method: application to the river Beiro basin (Spain) Natural Hazards and Earth System Science, 12, 327-340, 2012 Author(s): D. Costanzo, E. Rotigliano, C. Irigaray, J. D. Jiménez-Perálvarez, and J. Chacón A procedure to select the controlling factors connected to the slope instability has been defined. It allowed us to assess the landslide susceptibility in the Rio Beiro basin (about 10 km 2 ) over the northeastern area of the city of Granada (Spain). Field and remote (Google EarthTM) recognition techniques allowed us to generate a landslide inventory consisting in 127 phenomena. To discriminate between stable and unstable conditions, a diagnostic area had been chosen as the one limited to the crown and the toe of the scarp of the landslide. 15 controlling or determining factors have been defined considering topographic, geologic, geomorphologic and pedologic available data. Univariate tests, using both association coefficients and validation results of single-variable susceptibility models, allowed us to select the best predictors, which were combined for the unique conditions analysis. For each of the five recognised landslide typologies, susceptibility maps for the best models were prepared. In order to verify both the goodness of fit and the prediction skill of the susceptibility models, two different validation procedures were applied and compared. Both procedures are based on a random partition of the landslide archive for producing a test and a training subset. The first method is based on the analysis of the shape of the success and prediction rate curves, which are quantitatively analysed exploiting two morphometric indexes. The second method is based on the analysis of the degree of fit, by considering the relative error between the intersected target landslides by each of the different susceptibility classes in which the study area was partitioned. Both the validation procedures confirmed a very good predictive performance of the susceptibility models and of the actual procedure followed to select the controlling factors.

Description: Floodwater utilisation values of wetland services – a case study in Northeastern China Natural Hazards and Earth System Science, 12, 341-349, 2012 Author(s): S. B. Lü, S. G. Xu, and F. Feng Water plays a significant role in wetlands. Floodwater utilisation in wetlands brings a wide range of wetland services, from goods production and water regulation to animal protection and aesthetics related to water supply in wetlands. In this study, the floodwater utilisation values of wetland services were estimated within the Momoge wetland and Xianghai wetland in western Jilin province of northeastern China. From 2003 to 2008, the floodwater diverted from the Nenjiang and Tao'er River is 381 million m 3 , which translates into a monetary value of approximately 1.35 billion RMB in 2008 (RMB: Chinese Currency, RMB 6.80 = US$ 1), and the ratio of economic value, eco-environmental value, and social value is 1:12:2. Besides the monetary value of the water itself, excessive floodwater utilisation may bring losses to wetlands; the threshold floodwater utilisation volumes in wetlands are discussed. Floodwater utilisation can alleviate water shortages in wetlands, and the evaluation of floodwater utilisation in wetland services in monetary terms is a guide for the effective use of the floodwater resources and for the conservation of wetlands.

Description: Development of an operational coastal flooding early warning system Natural Hazards and Earth System Science, 12, 379-390, 2012 Author(s): D.-J. Doong, L. Z.-H. Chuang, L.-C. Wu, Y.-M. Fan, C. C. Kao, and J.-H. Wang Coastal floods are a consistent threat to oceanfront countries, causing major human suffering and substantial economic losses. Climate change is exacerbating the problem. An early warning system is essential to mitigate the loss of life and property from coastal flooding. The purpose of this study is to develop a coastal flooding early warning system (CoFEWs) by integrating existing sea-state monitoring technology, numerical ocean forecasting models, historical database and experiences, as well as computer science. The proposed system has capability of offering data for the past, information for the present and future. The system was developed for the Taiwanese coast due to its frequent threat by typhoons. An operational system without any manual work is the basic requirement of the system. Integration of various data sources is the system kernel. Numerical ocean models play an important role within the system because they provide data for assessment of possible flooding. The regional wave model (SWAN) that nested with the large domain wave model (NWW III) is operationally set up for coastal wave forecasting, in addition to the storm surge predicted by a POM model. Data assimilation technology is incorporated for enhanced accuracy. A warning signal is presented when the storm water level that accumulated from astronomical tide, storm surge, and wave-induced run-up exceeds the alarm sea level. This warning system has been in practical use for coastal flooding damage mitigation in Taiwan for years. An example of the system operation during the Typhoon Haitung which struck Taiwan in 2005 is illustrated in this study.

Description: Improving probabilistic flood forecasting through a data assimilation scheme based on genetic programming Natural Hazards and Earth System Science, 12, 3719-3732, 2012 Author(s): L. Mediero, L. Garrote, and A. Chavez-Jimenez Opportunities offered by high performance computing provide a significant degree of promise in the enhancement of the performance of real-time flood forecasting systems. In this paper, a real-time framework for probabilistic flood forecasting through data assimilation is presented. The distributed rainfall-runoff real-time interactive basin simulator (RIBS) model is selected to simulate the hydrological process in the basin. Although the RIBS model is deterministic, it is run in a probabilistic way through the results of calibration developed in a previous work performed by the authors that identifies the probability distribution functions that best characterise the most relevant model parameters. Adaptive techniques improve the result of flood forecasts because the model can be adapted to observations in real time as new information is available. The new adaptive forecast model based on genetic programming as a data assimilation technique is compared with the previously developed flood forecast model based on the calibration results. Both models are probabilistic as they generate an ensemble of hydrographs, taking the different uncertainties inherent in any forecast process into account. The Manzanares River basin was selected as a case study, with the process being computationally intensive as it requires simulation of many replicas of the ensemble in real time.

Description: Acoustic and seismic imaging of the Adra Fault (NE Alboran Sea): in search of the source of the 1910 Adra earthquake Natural Hazards and Earth System Science, 12, 3255-3267, 2012 Author(s): E. Gràcia, R. Bartolome, C. Lo Iacono, X. Moreno, D. Stich, J. J. Martínez-Diaz, G. Bozzano, S. Martínez-Loriente, H. Perea, S. Diez, E. Masana, J. J. Dañobeitia, O. Tello, J. L. Sanz, E. Carreño, and EVENT-SHELF Team Recently acquired swath-bathymetry data and high-resolution seismic reflection profiles offshore Adra (Almería, Spain) reveal the surficial expression of a NW–SE trending 20 km-long fault, which we termed the Adra Fault. Seismic imaging across the structure depicts a sub-vertical fault reaching the seafloor surface and slightly dipping to the NE showing an along-axis structural variability. Our new data suggest normal displacement of the uppermost units with probably a lateral component. Radiocarbon dating of a gravity core located in the area indicates that seafloor sediments are of Holocene age, suggesting present-day tectonic activity. The NE Alboran Sea area is characterized by significant low-magnitude earthquakes and by historical records of moderate magnitude, such as the M w = 6.1 1910 Adra Earthquake. The location, dimension and kinematics of the Adra Fault agree with the fault solution and magnitude of the 1910 Adra Earthquake, whose moment tensor analysis indicates normal-dextral motion. The fault seismic parameters indicate that the Adra Fault is a potential source of large magnitude ( M w ≤ 6.5) earthquakes, which represents an unreported seismic hazard for the neighbouring coastal areas.

Description: IR spectral analysis for the diagnostics of crust earthquake precursors Natural Hazards and Earth System Science, 12, 3269-3274, 2012 Author(s): R. M. Umarkhodgaev, V. A. Liperovsky, V. V. Mikhailin, V. V. Bogdanov, C.-V. Meister, and E. V. Liperovskaya Some possible physical processes are analysed that cause, under the condition of additional ionisation in a pre-breakdown electric field, emissions in the infrared (IR) interval. The atmospheric transparency region of the IR spectrum at wavelengths of 7–15 μm is taken into account. This transparency region corresponds to spectral lines of small atmospheric constituents like CH 4 , CO 2 , N 2 O, NO 2 , NO, and O 3 . The possible intensities of the IR emissions observable in laboratories and in nature are estimated. The acceleration process of the electrons in the pre-breakdown electrical field before its adhesion to the molecules is analyzed. For daytime conditions, modifications of the adsorption spectra of the scattered solar emissions are studied; for nighttime, variations of emission spectra may be used for the analysis.

Description: Propagation of Atlantic Ocean swells in the north Indian Ocean: a case study Natural Hazards and Earth System Science, 12, 3605-3615, 2012 Author(s): S. V. Samiksha, P. Vethamony, V. M. Aboobacker, and R. Rashmi An analysis of altimeter significant wave height data of May 2007 revealed the occurrence of an extreme weather event off southern tip of South Africa in the Atlantic Ocean, and generation of a series of very high swells at 40° S. These swells propagated towards northeast and broke over La Réunion island in the Indian Ocean on 12 May 2007. The wave model WAVEWATCH III was used to study the propagation of these swells in the Indian Ocean. The model was validated for the Indian Ocean using moored buoy data at 12 locations and merged altimeter wave data. The wave model accurately reproduced the event of May 2007. Swell heights, of the order of 15.0 m, at the generation area reduced to 6.0 m near La Réunion island. This study shows that the swells generated in the Roaring Forties of the Atlantic Ocean (between 15° to 80° E longitude) propagate in the NE/NNE direction towards the north Indian Ocean, and wave characteristics of the Arabian Sea are least influenced compared to that of Bay of Bengal, when swells from the Atlantic Ocean enter the Indian Ocean. The double peak spectrum extracted for the Bay of Bengal indicates that one of the peaks is due to swells generated off southern tip of South Africa.

Description: Monitoring methane emission of mud volcanoes by seismic tremor measurements: a pilot study Natural Hazards and Earth System Science, 12, 3617-3629, 2012 Author(s): D. Albarello, M. Palo, and G. Martinelli A new approach for estimating methane emission at mud volcanoes is here proposed based on measurements of the seismic tremor on their surface. Data obtained at the Dashgil mud volcano in Azerbaijan reveal the presence of energy bursts characterized by well-determined features (i.e. waveforms, spectra and polarization properties) that can be associated with bubbling at depth. Counting such events provides a possible tool for monitoring gas production in the reservoir, thus minimizing logistic troubles and representing a cheap and effective alternative to more complex approaches. Specifically, we model the energy bursts as the effect of resonant gas bubbles at depth. This modelling allows to estimate the dimension of the bubbles and, consequently, the gas outflow from the main conduit in the assumption that all emissions from depth occur by bubble uprising. The application of this model to seismic events detected at the Dashgil mud volcano during three sessions of measurements carried out in 2006 and 2007 provides gas flux estimates that are in line with those provided by independent measurements at the same structure. This encouraging result suggests that the one here proposed could be considered a new promising, cheap and easy to apply tool for gas flux measurements in bubbling gas seepage areas.

Description: Instabilities on Alpine temperate glaciers: new insights arising from the numerical modelling of Allalingletscher (Valais, Switzerland) Natural Hazards and Earth System Science, 12, 2977-2991, 2012 Author(s): J. Faillettaz, M. Funk, and D. Sornette The processes leading to a glacier instability depend on the thermal properties of the contact between the glacier and its bedrock. Assessing the stability of temperate glacier (i.e. the glacier can slide on its bedrock) remains problematic. In order to scrutinize in more detail the processes governing such "sliding" instabilities, a numerical model designed to investigate gravitational instabilities in heterogeneous media was further developed to account for the presence of water at the interface between the bedrock and the glacier for Allalingletscher. This model made it possible to account for various geometric configurations, interaction between sliding and tension cracking and water flow at the bedrock. We could show that both a critical geometrical configuration of the glacier tongue and the existence of a distributed subglacial drainage network were the main causes of the Allalingletscher catastrophic break-off. Moreover, the analysis of the modelling results diagnosed the phenomenon of recoupling of the glacier to its bed followed by a pulse of subglacial water flow as a potential new precursory sign of the final break-off in 1965. This model casts a gleam of hope for a better understanding of the ultimate rupture process resulting from such glacier sliding instabilities.

Description: Uncertainty of lateral boundary conditions in a convection-permitting ensemble: a strategy of selection for Mediterranean heavy precipitation events Natural Hazards and Earth System Science, 12, 2993-3011, 2012 Author(s): O. Nuissier, B. Joly, B. Vié, and V. Ducrocq This study examines the impact of lateral boundary conditions (LBCs) in convection-permitting (C-P) ensemble simulations with the AROME model driven by the ARPEGE EPS (PEARP). Particular attention is paid to two torrential rainfall episodes, observed on 15–16 June 2010 (the Var case) and 7–8 September 2010 (the Gard-Ardèche case) over the southeastern part of France. Regarding the substantial computing time for convection-permitting models, a methodology of selection of a few LBCs, dedicated for C-P ensemble simulations of heavy precipitation events is evaluated. Several sensitivity experiments are carried out to evaluate the skill of the AROME ensembles, using different approaches for selection of the driving PEARP members. The convective-scale predictability of the Var case is very low and it is driven primarily by a surface low over the Gulf of Lyon inducing a strong convergent low-level flow, and accordingly advecting strong moisture supply from the Mediterranean Sea toward the flooded area. The Gard-Ardèche case is better handled in ensemble simulations as a surface cold front moved slowly eastwards while increasing the low-level water vapour ahead is well reproduced. The selection based on a cluster analysis of the PEARP members generally better performs against a random selection. The consideration of relevant meteorological parameters for the convective events of interest (i.e. geopotential height at 500 hPa and horizontal moisture flux at 925 hPa) refined the cluster analysis. It also helps in better capturing the forecast uncertainty variability which is spatially more localized at the "high-impact region" due to the selection of more mesoscale parameters.

Description: Hydrometeorological threshold conditions for debris flow initiation in Norway Natural Hazards and Earth System Science, 12, 3059-3073, 2012 Author(s): N. K. Meyer, A. V. Dyrrdal, R. Frauenfelder, B. Etzelmüller, and F. Nadim Debris flows, triggered by extreme precipitation events and rapid snow melt, cause considerable damage to the Norwegian infrastructure every year. To define intensity-duration (ID) thresholds for debris flow initiation critical water supply conditions arising from intensive rainfall or snow melt were assessed on the basis of daily hydro-meteorological information for 502 documented debris flow events. Two threshold types were computed: one based on absolute ID relationships and one using ID relationships normalized by the local precipitation day normal (PDN). For each threshold type, minimum, medium and maximum threshold values were defined by fitting power law curves along the 10th, 50th and 90th percentiles of the data population. Depending on the duration of the event, the absolute threshold intensities needed for debris flow initiation vary between 15 and 107 mm day −1 . Since the PDN changes locally, the normalized thresholds show spatial variations. Depending on location, duration and threshold level, the normalized threshold intensities vary between 6 and 250 mm day −1 . The thresholds obtained were used for a frequency analysis of over-threshold events giving an estimation of the exceedance probability and thus potential for debris flow events in different parts of Norway. The absolute thresholds are most often exceeded along the west coast, while the normalized thresholds are most frequently exceeded on the west-facing slopes of the Norwegian mountain ranges. The minimum thresholds derived in this study are in the range of other thresholds obtained for regions with a climate comparable to Norway. Statistics reveal that the normalized threshold is more reliable than the absolute threshold as the former shows no spatial clustering of debris flows related to water supply events captured by the threshold.

Description: Crossing the digital divide: an interoperable solution for sharing time series and coverages in Earth sciences Natural Hazards and Earth System Science, 12, 3013-3029, 2012 Author(s): F. R. Salas, E. Boldrini, D. R. Maidment, S. Nativi, and B. Domenico In a world driven by the Internet and the readily accessible information it provides, there exists a high demand to easily discover and collect vast amounts of data available over several scientific domains and numerous data types. To add to the complexity, data is not only available through a plethora of data sources within disparate systems but also represents differing scales of space and time. One clear divide that exists in the world of information science and technology is the disjoint relationship between hydrologic and atmospheric science information. These worlds have long been split between observed time series at discrete geographical features in hydrologic science and modeled or remotely sensed coverages or grids over continuous space and time domains in atmospheric science. As more information becomes widely available through the Web, data are being served and published as Web services using standardized implementations and encodings. This paper illustrates a framework that utilizes Sensor Observation Services, Web Feature Services, Web Coverage Services, Catalog Services for the Web and GI-cat Services to index and discover data offered through different classes of information. This services infrastructure supports multiple servers of time series and gridded information, which can be searched through multiple portals, using a common set of time, space and concept query filters.

Description: Simulating dam-breach flood scenarios of the Tangjiashan landslide dam induced by the Wenchuan Earthquake Natural Hazards and Earth System Science, 12, 3031-3044, 2012 Author(s): X. Fan, C. X. Tang, C. J. van Westen, and D. Alkema Floods from failures of landslide dams can pose a hazard to people and property downstream, which have to be rapidly assessed and mitigated in order to reduce the potential risk. The Tangjiashan landslide dam induced by the M w = 7.9 2008 Wenchuan earthquake had impounded the largest lake in the earthquake affected area with an estimated volume of 3 × 10 8 m 3 , and the potential catastrophic dam breach posed a serious threat to more than 2.5 million people in downstream towns and Mianyang city, located 85 km downstream. Chinese authorities had to evacuate parts of the city until the Tangjiashan landslide dam was artificially breached by a spillway, and the lake was drained. We propose an integrated approach to simulate the dam-breach floods for a number of possible scenarios, to evaluate the severity of the threat to Mianyang city. Firstly, the physically-based BREACH model was applied to predict the flood hydrographs at the dam location, which were calibrated with observational data of the flood resulting from the artificial breaching. The output hydrographs from this model were inputted into the 1-D–2-D SOBEK hydrodynamic model to simulate the spatial variations in flood parameters. The simulated flood hydrograph, peak discharge and peak arrival time at the downstream towns fit the observations. Thus this approach is capable of providing reliable predictions for the decision makers to determine the mitigation plans. The sensitivity analysis of the BREACH model input parameters reveals that the average grain size, the unit weight and porosity of the dam materials are the most sensitive parameters. The variability of the dam material properties causes a large uncertainty in the estimation of the peak flood discharge and peak arrival time, but has little influence on the flood inundation area and flood depth downstream. The effect of cascading breaches of smaller dams downstream of the Tangjiashan dam was insignificant, due to their rather small volumes, which were only 2% of the volume of the Tangjiashan lake. The construction of the spillway was proven to have played a crucial role in reducing the dam-breach flood, because all the other natural breach scenarios would have caused the flooding of the downstream towns and parts of Mianyang city. However, in retrospect improvements on the spillway design and the evacuation planning would have been possible. The dam-break flood risk will be better controlled by reducing the spillway channel gradient and the porosity of the coating of the channel bottom. The experience and lessons we learned from the Tangjiashan case will contribute to improving the hazard mitigation and risk management planning of similar events in future.

Description: Geomorphic hazards and intense rainfall: the case study of the Recco Stream catchment (Eastern Liguria, Italy) Natural Hazards and Earth System Science, 12, 893-903, 2012 Author(s): F. Faccini, A. Robbiano, and A. Sacchini A critical pluviometric event occurred in the central-eastern Ligurian Riviera, 15 km from Genoa, on 1 June 2007. This event caused landslides and hydraulic problems between Sori and Camogli and in the inland area of the Recco Valley. An analysis of the heavy rainfall was conducted. Hourly precipitation data revealed a critical event between 04:00 a.m. and 07:00 a.m. local time, with more than 220 mm of precipitation over three hours. Slope movements were mainly debris flows that detached from the lateral valleys of the Recco Stream catchment and from well-maintained, wooded slopes that were also characterised by cultivated terraces. Numerous slide planes corresponded to the interface between the surface cover and the underlying bedrock, which presents an unfavourable geologic structure in terms of stability assessment. In most cases, the displaced material had a limited thickness. Debris cover was rapidly channelled along small valleys, which controlled the critical hydraulic conditions in the secondary drainage network. Man-made drainage systems were partially or totally blocked in a very short time and, like the natural watercourses, accumulated thick and extensive alluvial fans. Most of the instability phenomena occurred in areas that had been designated medium or low-risk areas during land planning, and in sectors that were defined as stable, because they lacked geomorphic indicators connected to landslide risks. The above considerations highlight some gaps of the Recco Stream Master Plan. Therefore, to update this land planning tool, it is necessary to extensively investigate local geomorphological characteristics and to adopt a different method for assigning weights to the geohazard maps.

Description: Lightning activity, rainfall and flash flooding – occasional or interrelated events? A case study in the island of Crete Natural Hazards and Earth System Science, 12, 881-891, 2012 Author(s): A. G. Koutroulis, M. G. Grillakis, I. K. Tsanis, V. Kotroni, and K. Lagouvardos The majority of cyclones passing over Crete in late autumn to early winter originate from southwest, west and northwest and are of varying size and intensity. A number of these cyclones cause flash floods. The present study reports the possible relationships between lighting activity and high precipitation related to flash flood events. In this study an attempt was made to correlate the lightning number and location, recorded by the ZEUS lightning detection system, with the rainfall characteristics for sixteen rain events (4 flood and 12 non-flood events) on the island of Crete, during the period 2008–2009. Spatiotemporal analysis of rain and rain rate with flash count was performed with respect to distance (radius) of flashes from raingauge location at various temporal scales, in order to examine the correlation of accumulated rainfall and lightning activity. The maximum attained statistical significant correlation was obtained within a circular area of an average radius of 15 km around the raingauge, and an average time lag of flash count prior precipitation accumulation of 15 min. The maximum correlation between the lightning and rainfall data is obtained for shorter time lags for the flood events (15 min) than the non-flood events (25 min), that could reflect the faster propagation of flood triggering storms due to high convective activity. Results show increased lightning activity occurring during flood triggering storms, by an average of four times higher. Furthermore, there is evidence that the number of flashes that occur during a precipitation event is related to precipitation depth when the latter is adequate to produce a flood event. Differences between flood and non-flood producing storms need to be further assessed by analyzing more independent parameters, including the synoptic conditions and dominant flash flood hydrological generating processes.

Description: Detailed rock failure susceptibility mapping in steep rocky coasts by means of non-contact geostructural surveys: the case study of the Tigullio Gulf (Eastern Liguria, Northern Italy) Natural Hazards and Earth System Science, 12, 867-880, 2012 Author(s): P. De Vita, A. Cevasco, and C. Cavallo In this study, an engineering geological analysis for the assessment of the rock failure susceptibility of a high, steep, rocky coast was developed by means of non-contact geostructural surveys. The methodology was applied to a 6-km coastal cliff located in the Gulf of Tigullio (Northern Tyrrhenian Sea) between Rapallo and Chiavari. The method is based on the geostructural characterisation of outcropping rock masses through meso- and macroscale stereoscopic analyses of digital photos that were taken continuously from a known distance from the coastline. The results of the method were verified through direct surveys of accessible sample areas. The rock failure susceptibility of the coastal sector was assessed by analysing the fundamental rock slope mechanisms of instability and the results were implemented into a Geographic Information System (GIS). The proposed method is useful for rock failure susceptibility assessments in high, steep, rocky coastal areas, where accessibility is limited due to cliffs or steep slopes. Moreover, the method can be applied to private properties or any other area where a complete and systematic analysis of rock mass structural features cannot be achieved. Compared to direct surveys and to other non-contact methods based on digital terrestrial photogrammetry, the proposed procedure provided good quality data of the structural features of the rock mass at a low cost. Therefore, the method could be applied to similar coastal areas with a high risk of rock failure occurrence.

Description: Geo-hydrological risk management for civil protection purposes in the urban area of Genoa (Liguria, NW Italy) Natural Hazards and Earth System Science, 12, 943-959, 2012 Author(s): P. Brandolini, A. Cevasco, M. Firpo, A. Robbiano, and A. Sacchini Over the past century the municipal area of Genoa has been affected by recurring flood events and several landslides that have caused severe damage to urbanized areas on both the coastal-fluvial plains and surrounding slopes, sometimes involving human casualties. The analysis of past events' annual distribution indicates that these phenomena have occurred with rising frequency in the last seventy years, following the main land use change due to the development of harbour, industrial, and residential areas, which has strongly impacted geomorphological processes. Consequently, in Genoa, civil protection activities are taking on an increasing importance for geo-hydrological risk mitigation. The current legislative framework assigns a key role in disaster prevention to municipalities, emergency plan development, as well as response action coordination in disaster situations. In view of the geomorphological and environmental complexity of the study area and referring to environmental laws, geo-hydrological risk mitigation strategies adopted by local administrators for civil protection purposes are presented as examples of current land/urban management related to geo-hydrological hazards. Adopted measures have proven to be effective on several levels (planning, management, structure, understanding, and publication) in different cases. Nevertheless, the last flooding event (4 November 2011) has shown that communication and public information concerning the perception of geo-hydrological hazard can be improved.

Description: Landslide hazard and land management in high-density urban areas of Campania region, Italy Natural Hazards and Earth System Science, 12, 905-926, 2012 Author(s): D. Di Martire, M. De Rosa, V. Pesce, M. A. Santangelo, and D. Calcaterra Results deriving from a research focused on the interplay between landslides and urban development are presented here, with reference to two densely populated settings located in the Campania region, Italy: the city of Naples and the island of Ischia. Both areas suffer adverse consequences from various types of landslides since at least 2000 yr. Our study evidences that, despite the long history of slope instabilities, the urban evolution, often illegal, disregarded the high landslide propensity of the hillsides; thus, unsafe lands have been occupied, even in recent years, when proper and strict rules have been enacted to downgrade the landslide risk. It is finally argued that future guidelines should not be entirely based upon physical countermeasures against mass movements. On the contrary, national and local authorities should enforce the territorial control, obliging citizens to respect the existing regulations and emphasizing the role of alternative, non-structural solutions.

Description: Ground subsidence geo-hazards induced by rapid urbanization: implications from InSAR observation and geological analysis Natural Hazards and Earth System Science, 12, 935-942, 2012 Author(s): F. Chen, H. Lin, Y. Zhang, and Z. Lu Due to the convenient transportation and construction, cities are prone to be situated in areas with flat terrain and unstable sediments, resulting in the concurrence of ground subsidence and urbanization. Here the interaction between geology, anthropogenic processes and ground subsidence geo-hazards were investigated in the Greater Pearl River Delta region of China. Geological evidences and 2006–2010 persistent scatterer data indicate that anthropogenic activities are dominant, although the distribution of river system and Quaternary sediments are also highly related to significant displacements (primarily at a rate of −15 to 15 mm a −1 ). The surface displacements derived by synthetic aperture radar interferometry suggest that the urbanization rhythm has to be routinely monitored. Considering analogous urbanization modes, particularly in developing countries, ground subsidence monitoring together with the analysis of its driving force are critical for geo-hazards early-warning, city planning as well as sustainable urbanization.

Description: A cautionary note regarding comparisons of fire danger indices Natural Hazards and Earth System Science, 12, 927-934, 2012 Author(s): C. S. Eastaugh, A. Arpaci, and H. Vacik Over the past decade, several methods have been used to compare the performance of fire danger indices in an effort to find the most appropriate indices for particular regions or circumstances. Various authors have proposed comparators and demonstrated different responses of indices to their tests, but rarely has much effort been put into demonstrating the validity of the comparators themselves. We present a demonstration that many of the published comparators are sensitive to the different frequency distributions, that may be inherent in the performance of the different indices, and outline a non-parametric method that may be useful for future work. We compare four hypothetical fire danger indices, three of which are simple mathematical transformations of each other. The hypothesis tested is that the comparators often used in such studies may indicate spurious performance differences between these indices, which is found to be the case. Non-parametric methods are robust to differences in index value frequency distribution and may allow more valid comparisons of fire danger indices. The new comparison method is shown to have advantages over other non-parametric comparators.

Description: Past and recent trends in the western Black Sea storminess Natural Hazards and Earth System Science, 12, 961-977, 2012 Author(s): N. N. Valchev, E. V. Trifonova, and N. K. Andreeva Storms are one of the most important phenomena producing coastal hazards and endangering human life and activities. In recent decades storm climate has become a subject of increased public awareness and knowledge of this issue can help the society to meet future challenges related to extreme storm manifestation. Therefore, the goal of this study is to assess trends in past and recent storminess in the western Black Sea. The analysis of storm climate is based on a continuous hindcast dataset covering a substantial historical time-span of 63 yr (1948–2010). It was used to create a storm population and to estimate properties describing storminess (proxies). This was done by introduction of criteria allowing separation of events with low probability of occurrence and at the same time keeping the information on their pattern, i.e. properties of storm phases. Eleven storminess proxies were analysed and the most indicative appeared to be storm duration; integral, mean and specific storm wave energy; and wind velocity and direction, which were obtained for each storm season. While experiencing significant variability on a quasi-decadal scale, no significant upward or downward trends in storminess were detected. For almost all proxies, an increasing trend until the 1980s or the 1990s and a return to average or even calm conditions in the late 2000s are traceable. On this background, a steady although not significant increase of wind velocity was detected. Results also indicate an alteration of storm pattern, manifested as shortening of storm duration due to a shift of the prevailing direction of storm forcing winds to the north. Nevertheless, incident wave energy in the storms' most intense phase remains significant. The obtained results are discussed with regard to the influence of the North Atlantic Oscillation on the hydrometeorological pattern of the Black Sea region as a part of the European-Atlantic area, in particular with respect to the cyclonic activity.

Description: Structural damages observed in state buildings after Simav/Turkey earthquake occurred on 19 May 2011 Natural Hazards and Earth System Science, 12, 2709-2718, 2012 Author(s): Y. S. Tama Different levels of damages occurred in state buildings, especially in educational facilities, during the Simav earthquake ( M L =5.7) on 19 May 2011. A site survey was carried out in the area after the earthquake, where six state buildings were examined in detail. The results of the survey showed that main reasons for the formation of damages in these buildings are the use of low strength concrete, insufficient reinforcement, inappropriate detailing, and low-quality workmanship. The investigated buildings were also evaluated by P25-rapid assessment method. The method demonstrates that two of the buildings in question are in "high risk band"; the other two fall into "detailed evaluation band", and the rest are in the "low risk band". This figure also matches with the damages observed in the site survey.

Description: Developing Tsunami fragility curves using remote sensing and survey data of the 2010 Chilean Tsunami in Dichato Natural Hazards and Earth System Science, 12, 2689-2697, 2012 Author(s): E. Mas, S. Koshimura, A. Suppasri, M. Matsuoka, M. Matsuyama, T. Yoshii, C. Jimenez, F. Yamazaki, and F. Imamura On 27 February 2010, a megathrust earthquake of M w = 8.8 generated a destructive tsunami in Chile. It struck not only Chilean coast but propagated all the way to Japan. After the event occurred, the post-tsunami survey team was assembled, funded by the Japan Science and Technology Agency (JST), to survey the area severely affected by the tsunami. The tsunami damaged and destroyed numerous houses, especially in the town of Dichato. In order to estimate the structural fragility against tsunami hazard in this area, tsunami fragility curves were developed. Surveyed data of inundation depth and visual inspection of satellite images of Dichato were used to classify the damage to housing. A practical method suitable when there are limitations on available data for numerical simulation or damage evaluation from surveys is presented here. This study is the first application of tsunami fragility curves on the South American Pacific coast and it might be of practical use for communities with similar characteristics along the west Pacific coast. The proposed curve suggests that structures in Dichato will be severely damaged – with a 68% probability – already at 2 m tsunami inundation depth.

Description: Multivariate return periods of sea storms for coastal erosion risk assessment Natural Hazards and Earth System Science, 12, 2699-2708, 2012 Author(s): S. Corbella and D. D. Stretch The erosion of a beach depends on various storm characteristics. Ideally, the risk associated with a storm would be described by a single multivariate return period that is also representative of the erosion risk, i.e. a 100 yr multivariate storm return period would cause a 100 yr erosion return period. Unfortunately, a specific probability level may be associated with numerous combinations of storm characteristics. These combinations, despite having the same multivariate probability, may cause very different erosion outcomes. This paper explores this ambiguity problem in the context of copula based multivariate return periods and using a case study at Durban on the east coast of South Africa. Simulations were used to correlate multivariate return periods of historical events to return periods of estimated storm induced erosion volumes. In addition, the relationship of the most-likely design event (Salvadori et al., 2011) to coastal erosion was investigated. It was found that the multivariate return periods for wave height and duration had the highest correlation to erosion return periods. The most-likely design event was found to be an inadequate design method in its current form. We explore the inclusion of conditions based on the physical realizability of wave events and the use of multivariate linear regression to relate storm parameters to erosion computed from a process based model. Establishing a link between storm statistics and erosion consequences can resolve the ambiguity between multivariate storm return periods and associated erosion return periods.

Description: Heavy precipitation events in the Mediterranean: sensitivity to cloud physics parameterisation uncertainties Natural Hazards and Earth System Science, 12, 2671-2688, 2012 Author(s): S. Fresnay, A. Hally, C. Garnaud, E. Richard, and D. Lambert In autumn, southeastern France is often affected by heavy precipitation events which may result in damaging flash-floods. The 20 October and 1 November 2008 are two archetypes of the meteorological situations under which these events occur: an upper-level trough directing a warm and moist flow from the Mediterranean towards the Cévennes ridge or a quasi stationary meso-scale convective complex developing over the Rhone valley. These two types of events exhibit a contrasting level of predictability; the former being usually better forecast than the latter. Control experiments performed with the Meso-NH model run with a 2.5 km resolution confirm these predictability issues. The deterministic forecast of the November case (Cévennes ridge) is found to be much more skilful than the one for the October case (Rhone valley). These two contrasting situations are used to investigate the sensitivity of the model for cloud physics parameterisation uncertainties. Three 9-member ensembles are constructed. In the first one, the rain distribution intercept parameter is varied within its range of allowed values. In the second one, random perturbations are applied to the rain evaporation rate, whereas in the third one, random perturbations are simultaneously applied to the cloud autoconversion, rain accretion, and rain evaporation rates. Results are assessed by comparing the time and space distribution of the observed and forecasted precipitation. For the Rhone valley case, it is shown that not one of the ensembles is able to drastically improve the skill of the forecast. Taylor diagrams indicate that the microphysical perturbations are more efficient in modulating the rainfall intensities than in altering their localization. Among the three ensembles, the multi-process perturbation ensemble is found to yield the largest spread for most parameters. In contrast, the results of the Cévennes case exhibit almost no sensitivity to the microphysical perturbations. These results clearly show that the usefulness of an ensemble prediction system based upon microphysical perturbations is case dependent. Additional experiments indicate a greater potential for the multi-process ensemble when the model resolution is increased to 500 m.

Description: A lightning climatology of the South-West Indian Ocean Natural Hazards and Earth System Science, 12, 2659-2670, 2012 Author(s): C. Bovalo, C. Barthe, and N. Bègue The World Wide Lightning Location Network (WWLLN) data have been used to perform a lightning climatology in the South-West Indian Ocean (SWIO) region from 2005 to 2011. Maxima of lightning activity were found in the Maritime Continent and southwest of Sri Lanka (〉50 fl km −2 yr −1 ) but also over Madagascar and above the Great Lakes of East Africa (〉10–20 fl km −2 yr −1 ). Lightning flashes within tropical storms and tropical cyclones represent 50 % to 100 % of the total lightning activity in some oceanic areas of the SWIO (between 10° S and 20° S). The SWIO is characterized by a wet season (November to April) and a dry season (May to October). As one could expect, lightning activity is more intense during the wet season as the Inter Tropical Convergence Zone (ITCZ) is present over all the basin. Flash density is higher over land in November–December–January with values reaching 3–4 fl km −2 yr −1 over Madagascar. During the dry season, lightning activity is quite rare between 10° S and 25° S. The Mascarene anticyclone has more influence on the SWIO resulting in shallower convection. Lightning activity is concentrated over ocean, east of South Africa and Madagascar. A statistical analysis has shown that El Niño–Southern Oscillation mainly modulates the lightning activity up to 56.8% in the SWIO. The Indian Ocean Dipole has a significant contribution since ~49% of the variability is explained by this forcing in some regions. The Madden–Julian Oscillation did not show significative impact on the lightning activity in our study.

Description: Rainfall and earthquake-induced landslide susceptibility assessment using GIS and Artificial Neural Network Natural Hazards and Earth System Science, 12, 2719-2729, 2012 Author(s): Y. Li, G. Chen, C. Tang, G. Zhou, and L. Zheng A GIS-based method for the assessment of landslide susceptibility in a selected area of Qingchuan County in China is proposed by using the back-propagation Artificial Neural Network model (ANN). Landslide inventory was derived from field investigation and aerial photo interpretation. 473 landslides occurred before the Wenchuan earthquake (which were thought as rainfall-induced landslides (RIL) in this study), and 885 earthquake-induced landslides (EIL) were recorded into the landslide inventory map. To understand the different impacts of rainfall and earthquake on landslide occurrence, we first compared the variations between landslide spatial distribution and conditioning factors. Then, we compared the weight variation of each conditioning factor derived by adjusting ANN structure and factors combination respectively. Last, the weight of each factor derived from the best prediction model was applied to the entire study area to produce landslide susceptibility maps. Results show that slope gradient has the highest weight for landslide susceptibility mapping for both RIL and EIL. The RIL model built with four different factors (slope gradient, elevation, slope height and distance to the stream) shows the best success rate of 93%; the EIL model built with five different factors (slope gradient, elevation, slope height, distance to the stream and distance to the fault) has the best success rate of 98%. Furthermore, the EIL data was used to verify the RIL model and the success rate is 92%; the RIL data was used to verify the EIL model and the success rate is 53%.

Description: Urban modelling for seismic prone areas: the case study of Vila Franca do Campo (Azores Archipelago, Portugal) Natural Hazards and Earth System Science, 12, 2731-2741, 2012 Author(s): V. N. Martins, P. Cabral, and D. Sousa e Silva Seismic risk mitigation comprises of land-use planning policies that enable risk reduction in areas exposed to earthquakes. Thus, the assessment of land-use plans regarding urban growth in seismic prone areas is very important. This article analyses the urban expansion of Vila Franca do Campo (island of S. Miguel, Azores, Portugal) from 1994 to 2005 based on ortophotomaps interpretations and simulates a scenario of urban growth for the year 2016 with a Land-use and Cover-Change (LUCC) model (Geomod). The goal is to evaluate the potential impact of land-use plans in managing urban growth and promoting seismic risk mitigation. Results indicate that the urban expansion, between 1994 and 2005, was done according to the Municipal Master Plan (MMP) restrictions. The scenario modelled for the year 2016 is potentially stricter for urban growth because it adds to the previous plan the constraints defined by the South Coast Management Plan (SCMP) that entered into force in 2007. In both time periods, a continuing urban growth towards seismic areas was identified. The absence of seismic risk mitigation policies and measures on both plans may contribute to increase the seismic hazard exposure and vulnerability. The results of this study strongly suggest the reformulation of future land-use plans to include seismic risk mitigation goals and policies.

Description: A hydrological analysis of the 4 November 2011 event in Genoa Natural Hazards and Earth System Science, 12, 2743-2752, 2012 Author(s): F. Silvestro, S. Gabellani, F. Giannoni, A. Parodi, N. Rebora, R. Rudari, and F. Siccardi On the 4 November 2011 a flash flood event hit the area of Genoa with dramatic consequences. Such an event represents, from the meteorological and hydrological perspective, a paradigm of flash floods in the Mediterranean environment. The hydro-meteorological probabilistic forecasting system for small and medium size catchments in use at the Civil Protection Centre of Liguria region exhibited excellent performances for the event, by predicting, 24–48 h in advance, the potential level of risk associated with the forecast. It greatly helped the decision makers in issuing a timely and correct alert. In this work we present the operational outputs of the system provided during the Liguria events and the post event hydrological modelling analysis that has been carried out accounting also for the crowd sourcing information and data. We discuss the benefit of the implemented probabilistic systems for decision-making under uncertainty, highlighting how, in this case, the multi-catchment approach used for predicting floods in small basins has been crucial.

Description: Hydro-meteorological evaluation of a convection-permitting ensemble prediction system for Mediterranean heavy precipitating events Natural Hazards and Earth System Science, 12, 2631-2645, 2012 Author(s): B. Vié, G. Molinié, O. Nuissier, B. Vincendon, V. Ducrocq, F. Bouttier, and E. Richard An assessment of the performance of different convection-permitting ensemble prediction systems (EPSs) is performed, with a focus on Heavy Precipitating Events (HPEs). The convective-scale EPS configuration includes perturbations of lateral boundary conditions (LBCs) by using a global ensemble to provide LBCs, initial conditions (ICs) through an ensemble data assimilation technique and perturbations of microphysical parameterisations to account for part of model errors. A probabilistic evaluation is conducted over an 18-day period. A clear improvement is found when uncertainties on LBCs and ICs are considered together, but the chosen microphysical perturbations have no significant impact on probabilistic scores. Innovative evaluation processes for three HPE case studies are implemented. First, maxima diagrams provide a multi-scale analysis of intense rainfall. Second, an hydrological evaluation is performed through the computation of discharge forecasts using hourly ensemble precipitation forecasts as an input. All ensembles behave similarly, but differences are found highlighting the impact of microphysical perturbations on HPEs forecasts, especially for cases involving complex small-scale processes.

Description: Analysis of intense rainfall events on Madeira Island during the 2009/2010 winter Natural Hazards and Earth System Science, 12, 2225-2240, 2012 Author(s): F. T. Couto, R. Salgado, and M. J. Costa This paper constitutes a step towards the understanding of some characteristics associated with high rainfall amounts and flooding on Madeira Island. The high precipitation events that occurred during the winter of 2009/2010 have been considered with three main goals: to analyze the main atmospheric characteristics associated with the events; to expand the understanding of the interaction between the island and the atmospheric circulations, mainly the effects of the island on the generation or intensification of orographic precipitation; and to evaluate the performance of high resolution numerical modeling in simulating and forecasting heavy precipitation events over the island. The MESO-NH model with a horizontal resolution of 1 km is used, as well as rain gauge data, synoptic charts and measurements of precipitable water obtained from the Atmospheric InfraRed Sounder (AIRS). The results confirm the influence of the orographic effects on precipitation over Madeira as well as the tropical–extratropical interaction, since atmospheric rivers were detected in six out of the seven cases analyzed, acting as a low level moisture supplier, which together with the orographic lifting induced the high rainfall amounts. Only in one of the cases the presence of a low pressure system was identified over the archipelago.

Description: Strengths and strain energies of volcanic edifices: implications for eruptions, collapse calderas, and landslides Natural Hazards and Earth System Science, 12, 2241-2258, 2012 Author(s): A. Gudmundsson Natural hazards associated with volcanic edifices depend partly on how fracture resistant the edifices are, i.e. on their strengths. Observations worldwide indicate that large fluid-driven extension fractures (dikes, inclined sheets), shear fractures (landslides), and mixed-mode fractures (ring dikes and ring faults) normally propagate more easily in a basaltic edifice (shield volcano) than in a stratovolcano. For example, dike-fed eruptions occur once every few years in many basaltic edifices but once every 10 2-3 yr in many stratovolcanoes. Large landslides and caldera collapses also appear to be more common in a typical basaltic edifice/shield volcano than in a typical stratovolcano. In contrast to a basaltic edifice, a stratovolcano is composed of mechanically dissimilar rock layers, i.e. layers with mismatching elastic properties (primarily Young's modulus). Elastic mismatch encourages fracture deflection and arrest at contacts and increases the amount of energy needed for a large-scale edifice failure. Fracture-related hazards depend on the potential energy available to propagate the fractures which, in turn, depends on the boundary conditions during fracture propagation. Here there are two possible scenarios: one in which the outer boundary of the volcanic edifice or rift zone does not move during the fracture propagation (constant displacement); the other in which the boundary moves (constant load). In the former, the total potential energy is the strain energy stored in the volcano before fracture formation; in the latter, the total potential energy is the strain energy plus the work done by the forces moving the boundary. Constant-displacement boundary conditions favor small eruptions, landslides, and caldera collapses, whereas constant-load conditions favor comparatively large eruptions, landslides, and collapses. For a typical magma chamber (sill-like with a diameter of 8 km), the strain energy change due to magma-chamber inflation is estimated at the order of 10 14 J (0.1 PJ). For comparison, the surface energy needed to form a typical feeder dike is of the same order of magnitude, or 10 14 J. There are several processes besides magma-chamber inflation that may increase the strain energy in a volcano before eruption. Thus, during a typical unrest period with magma-chamber inflation, the added strain energy in the volcano is large enough for a typical feeder dike to form. An injected dike, however, only reaches the surface and becomes a feeder if it is able to propagate through the numerous layers and contacts that tend to deflect or arrest dikes. The strong elastic mismatch between layers that constitute stratovolcanoes not only encourages fracture arrest, but also the storage of more strain energy (than in a typical basaltic edifice/shield volcano) before fracture formation and failure. It is thus through producing materials of widely different mechanical properties that stratovolcanoes become strong and resilient.

Description: Multi-parametric investigation of the volcano-hydrothermal system at Tatun Volcano Group, Northern Taiwan Natural Hazards and Earth System Science, 12, 2259-2270, 2012 Author(s): S. Rontogianni, K. I. Konstantinou, and C.-H. Lin The Tatun Volcano Group (TVG) is located in northern Taiwan near the capital Taipei. In this study we selected and analyzed almost four years (2004–2007) of its seismic activity. The seismic network established around TVG initially consisted of eight three-component seismic stations with this number increasing to twelve by 2007. Local seismicity mainly involved high frequency (HF) earthquakes occurring as isolated events or as part of spasmodic bursts. Mixed and low frequency (LF) events were observed during the same period but more rarely. During the analysis we estimated duration magnitudes for the HF earthquakes and used a probabilistic non-linear method to accurately locate all these events. The complex frequencies of LF events were also analyzed with the Sompi method indicating fluid compositions consistent with a misty or dusty gas. We juxtaposed these results with geochemical/temperature anomalies extracted from fumarole gas and rainfall levels covering a similar period. This comparison is interpreted in the context of a model proposed earlier for the volcano-hydrothermal system of TVG where fluids and magmatic gases ascend from a magma body that lies at around 7–8 km depth. Most HF earthquakes occur as a response to stresses induced by fluid circulation within a dense network of cracks pervading the upper crust at TVG. The largest ( M L ~ 3.1) HF event that occurred on 24 April 2006 at a depth of 5–6 km had source characteristics compatible with that of a tensile crack. It was followed by an enrichment in magmatic components of the fumarole gases as well as a fumarole temperature increase, and provides evidence for ascending fluids from a magma body into the shallow hydrothermal system. This detailed analysis and previous physical volcanology observations at TVG suggest that the region is volcanically active and that measures to mitigate potential hazards have to be considered by the local authorities.

Description: Brief communication "An auto-diagnosis tool to highlight interdependencies between urban technical networks" Natural Hazards and Earth System Science, 12, 2219-2224, 2012 Author(s): M. Toubin, D. Serre, Y. Diab, and R. Laganier Natural hazards threaten the urban system and its components that are likely to fail. With their high degree of interdependency, urban networks and services are critical issues for the resilience of a city. And yet, network managers are scarcely aware of their flaws and dependencies and they are reluctant to take them into account. In order to develop an operational tool to improve urban resilience, we propose here an auto-diagnosis method to be completed by network managers. The subsequent confrontation of all diagnoses is the basis of collaborative research for problem identification and solution design. The tool is experimented with the Parisian urban transport society.

Description: Three-dimensional earthquake analysis of roller-compacted concrete dams Natural Hazards and Earth System Science, 12, 2369-2388, 2012 Author(s): M. E. Kartal Ground motion effect on a roller-compacted concrete (RCC) dams in the earthquake zone should be taken into account for the most critical conditions. This study presents three-dimensional earthquake response of a RCC dam considering geometrical non-linearity. Besides, material and connection non-linearity are also taken into consideration in the time-history analyses. Bilinear and multilinear kinematic hardening material models are utilized in the materially non-linear analyses for concrete and foundation rock respectively. The contraction joints inside the dam blocks and dam–foundation–reservoir interaction are modeled by the contact elements. The hydrostatic and hydrodynamic pressures of the reservoir water are modeled with the fluid finite elements based on the Lagrangian approach. The gravity and hydrostatic pressure effects are employed as initial condition before the strong ground motion. In the earthquake analyses, viscous dampers are defined in the finite element model to represent infinite boundary conditions. According to numerical solutions, horizontal displacements increase under hydrodynamic pressure. Besides, those also increase in the materially non-linear analyses of the dam. In addition, while the principle stress components by the hydrodynamic pressure effect the reservoir water, those decrease in the materially non-linear time-history analyses.

Description: Seasonal forecast of French Mediterranean heavy precipitating events linked to weather regimes Natural Hazards and Earth System Science, 12, 2389-2398, 2012 Author(s): J.-F. Guérémy, N. Laanaia, and J.-P. Céron Seasonal predictability of local precipitation is rather weak in the mid-latitudes. This is the case when assessing the skill of the seasonal forecast of Heavy Precipitating Event (HPE) extreme occurrence over the French Mediterranean coast during the fall season. Tropics to extra-tropics teleconnection patterns do appear when averaging analyzed fields over the years characterised by a frequency of HPE occurrence in the upper 17% of the distribution. A methodology taking weather regime occurrence into account as an intermediate step to forecast HPE extreme occurrence is presented. For the period 1960 to 2001 and four different sets of seasonal forecast, the Economical Value is doubled, compared to the score obtained with the simulated local precipitation data, when using a linear model (Linear Discriminant Analysis in this case) taking simulated 200 hPa velocity potential–stream function regime occurrences as predictors. Interestingly, larger scores are shown for this couple of fields over a large-scale domain including the tropics than for the 500 hPa geopotential height over an Euro–Atlantic domain, despite a tighter link of the latter field to the local precipitation.

Description: Web-based Tsunami Early Warning System: a case study of the 2010 Kepulaunan Mentawai Earthquake and Tsunami Natural Hazards and Earth System Science, 12, 1855-1871, 2012 Author(s): E. Ulutas, A. Inan, and A. Annunziato This study analyzes the response of the Global Disasters Alerts and Coordination System (GDACS) in relation to a case study: the Kepulaunan Mentawai earthquake and related tsunami, which occurred on 25 October 2010. The GDACS, developed by the European Commission Joint Research Center, combines existing web-based disaster information management systems with the aim to alert the international community in case of major disasters. The tsunami simulation system is an integral part of the GDACS. In more detail, the study aims to assess the tsunami hazard on the Mentawai and Sumatra coasts: the tsunami heights and arrival times have been estimated employing three propagation models based on the long wave theory. The analysis was performed in three stages: (1) pre-calculated simulations by using the tsunami scenario database for that region, used by the GDACS system to estimate the alert level; (2) near-real-time simulated tsunami forecasts, automatically performed by the GDACS system whenever a new earthquake is detected by the seismological data providers; and (3) post-event tsunami calculations using GCMT (Global Centroid Moment Tensor) fault mechanism solutions proposed by US Geological Survey (USGS) for this event. The GDACS system estimates the alert level based on the first type of calculations and on that basis sends alert messages to its users; the second type of calculations is available within 30–40 min after the notification of the event but does not change the estimated alert level. The third type of calculations is performed to improve the initial estimations and to have a better understanding of the extent of the possible damage. The automatic alert level for the earthquake was given between Green and Orange Alert, which, in the logic of GDACS, means no need or moderate need of international humanitarian assistance; however, the earthquake generated 3 to 9 m tsunami run-up along southwestern coasts of the Pagai Islands where 431 people died. The post-event calculations indicated medium-high humanitarian impacts.

Description: Debris flood hazard documentation and mitigation on the Tilcara alluvial fan (Quebrada de Humahuaca, Jujuy province, North-West Argentina) Natural Hazards and Earth System Science, 12, 1873-1882, 2012 Author(s): G. Marcato, G. Bossi, F. Rivelli, and L. Borgatti For some decades, mass wasting processes such as landslides and debris floods have been threatening villages and transportation routes in the Rio Grande Valley, named Quebrada de Humauhuaca. One of the most significant examples is the urban area of Tilcara, built on a large alluvial fan. In recent years, debris flood phenomena have been triggered in the tributary valley of the Huasamayo Stream and reached the alluvial fan on a decadal basis. In view of proper development of the area, hazard and risk assessment together with risk mitigation strategies are of paramount importance. The need is urgent also because the Quebrada de Humahuaca was recently included in the UNESCO World Cultural Heritage. Therefore, the growing tourism industry may lead to uncontrolled exploitation and urbanization of the valley, with a consequent increase of the vulnerability of the elements exposed to risk. In this context, structural and non structural mitigation measures not only have to be based on the understanding of natural processes, but also have to consider environmental and sociological factors that could hinder the effectiveness of the countermeasure works. The hydrogeological processes are described with reference to present-day hazard and risk conditions. Considering the socio-economic context, some possible interventions are outlined, which encompass budget constraints and local practices. One viable solution would be to build a protecting dam upstream of the fan apex and an artificial channel, in order to divert the floodwaters in a gully that would then convey water and sediments into the Rio Grande, some kilometers downstream of Tilcara. The proposed remedial measures should employ easily available and relatively cheap technologies and local workers, incorporating low environmental and visual impacts issues, in order to ensure both the future conservation of the site and its safe exploitation for inhabitants and tourists.

Description: Development of tsunami early warning systems and future challenges Natural Hazards and Earth System Science, 12, 1923-1935, 2012 Author(s): J. Wächter, A. Babeyko, J. Fleischer, R. Häner, M. Hammitzsch, A. Kloth, and M. Lendholt Fostered by and embedded in the general development of information and communications technology (ICT), the evolution of tsunami warning systems (TWS) shows a significant development from seismic-centred to multi-sensor system architectures using additional sensors (e.g. tide gauges and buoys) for the detection of tsunami waves in the ocean. Currently, the beginning implementation of regional tsunami warning infrastructures indicates a new phase in the development of TWS. A new generation of TWS should not only be able to realise multi-sensor monitoring for tsunami detection. Moreover, these systems have to be capable to form a collaborative communication infrastructure of distributed tsunami warning systems in order to implement regional, ocean-wide monitoring and warning strategies. In the context of the development of the German Indonesian Tsunami Early Warning System (GITEWS) and in the EU-funded FP6 project Distant Early Warning System (DEWS), a service platform for both sensor integration and warning dissemination has been newly developed and demonstrated. In particular, standards of the Open Geospatial Consortium (OGC) and the Organization for the Advancement of Structured Information Standards (OASIS) have been successfully incorporated. In the FP7 project Collaborative, Complex and Critical Decision-Support in Evolving Crises (TRIDEC), new developments in ICT (e.g. complex event processing (CEP) and event-driven architecture (EDA)) are used to extend the existing platform to realise a component-based technology framework for building distributed tsunami warning systems.

Description: Analysis of microseismic signals and temperature recordings for rock slope stability investigations in high mountain areas Natural Hazards and Earth System Science, 12, 2283-2298, 2012 Author(s): C. Occhiena, V. Coviello, M. Arattano, M. Chiarle, U. Morra di Cella, M. Pirulli, P. Pogliotti, and C. Scavia The permafrost degradation is a probable cause for the increase of rock instabilities and rock falls observed in recent years in high mountain areas, particularly in the Alpine region. The phenomenon causes the thaw of the ice filling rock discontinuities; the water deriving from it subsequently freezes again inducing stresses in the rock mass that may lead, in the long term, to rock falls. To investigate these processes, a monitoring system composed by geophones and thermometers was installed in 2007 at the Carrel hut (3829 m a.s.l., Matterhorn, NW Alps). In 2010, in the framework of the Interreg 2007–2013 Alcotra project no. 56 MASSA, the monitoring system has been empowered and renovated in order to meet project needs. In this paper, the data recorded by this renewed system between 6 October 2010 and 5 October 2011 are presented and 329 selected microseismic events are analysed. The data processing has concerned the classification of the recorded signals, the analysis of their distribution in time and the identification of the most important trace characteristics in time and frequency domain. The interpretation of the results has evidenced a possible correlation between the temperature trend and the event occurrence. The research is still in progress and the data recording and interpretation are planned for a longer period to better investigate the spatial-temporal distribution of microseismic activity in the rock mass, with specific attention to the relation of microseismic activity with temperatures. The overall goal is to verify the possibility to set up an effective monitoring system for investigating the stability of a rock mass under permafrost conditions, in order to supply the researchers with useful data to better understand the relationship between temperature and rock mass stability and, possibly, the technicians with a valid tool for decision-making.

Description: Risk perception – issues for flood management in Europe Natural Hazards and Earth System Science, 12, 2299-2309, 2012 Author(s): R. A. Bradford, J. J. O'Sullivan, I. M. van der Craats, J. Krywkow, P. Rotko, J. Aaltonen, M. Bonaiuto, S. De Dominicis, K. Waylen, and K. Schelfaut Public perception of flood risk and flood risk information is often overlooked when developing flood risk management plans. As scientists and the public at large perceive risk in very different ways, flood risk management strategies are known to have failed in the past due to this disconnect between authorities and the public. This paper uses a novel approach in exploring the role of public perception in developing flood risk communication strategies in Europe. Results are presented of extensive quantitative research of 1375 questionnaire responses from thirteen communities at risk across six European countries. The research forms part of two research projects funded under the 2nd ERA-Net CRUE Funding Initiative: URFlood and FREEMAN. Risk perception is conceptualised as a pillar of social resilience, representing an innovative approach to the issue. From this process recommendations are identified for improving flood risk management plans through public participation.

Description: Uncorrected land-use planning highlighted by flooding: the Alba case study (Piedmont, Italy) Natural Hazards and Earth System Science, 12, 2329-2346, 2012 Author(s): F. Luino, L. Turconi, C. Petrea, and G. Nigrelli Alba is a town of over 30 000 inhabitants located along the Tanaro River (Piedmont, northwestern Italy) and is famous for its wine and white truffles. Many important industries and companies are based in Alba, including the famous confectionery group Ferrero. The town suffered considerably from a flood that occurred on 5–6 November 1994. Forty-eight percent of the urban area was inundated, causing severe damage and killing nine people. After the flood, the Alba area was analysed in detail to determine the reasons for its vulnerability. Information on serious floods in this area since 1800 was gathered from official records, state technical office reports, unpublished documents in the municipal archives, and articles published in local and national newspapers. Maps, plans and aerial photographs (since 1954) were examined to reconstruct Alba's urban development over the last two centuries and the planform changes of the Tanaro River. The results were compared with the effects of the November 1994 flood, which was mapped from aerial photographs taken immediately after the flood, field surveys and eyewitness reports. The territory of Alba was subdivided into six categories: residential; public service; industrial, commercial and hotels; sports areas, utilities and standards (public gardens, parks, athletics grounds, private and public sport clubs); aggregate plants and dumps; and agriculture and riverine strip. The six categories were then grouped into three classes with different flooding-vulnerability levels according to various parameters. Using GIS, the three river corridors along the Tanaro identified by the Autorità di Bacino del Fiume Po were overlaid on the three classes to produce a final map of the risk areas. This study shows that the historic floods and their dynamics have not been duly considered in the land-use planning of Alba. The zones that were most heavily damaged in the 1994 flood were those that were frequently affected in the past and sites of more recent urbanisation. Despite recurrent severe flooding of the Tanaro River and its tributaries, areas along the riverbed and its paleochannels have been increasingly used for infrastructure and building (e.g., roads, a municipal dump, a prison, natural aggregate plants, a nomad camp), which has often interfered with the natural spread of the floodwaters. Since the 1994 flood, many remedial projects have been completed along the Tanaro and its tributaries, including levees, bank protection, concrete walls and floodway channels. In spite of these costly projects, some areas remain at high risk for flooding. The method used, which considered historical data, river corridors identified by hydraulic calculations, geomorphological aspects and land-use planning, can indicate with good accuracy flood-prone areas and in consequence to be an useful tool for the coherent planning of urban expansion and the mitigation of flood risk.

Description: Active faults and historical earthquakes in the Messina Straits area (Ionian Sea) Natural Hazards and Earth System Science, 12, 2311-2328, 2012 Author(s): A. Polonia, L. Torelli, L. Gasperini, and P. Mussoni The Calabrian Arc (CA) subduction complex is located at the toe of the Eurasian Plate in the Ionian Sea, where sediments resting on the lower plate have been scraped off and piled up in the accretionary wedge due to the African/Eurasian plate convergence and back arc extension. The CA has been struck repeatedly by destructive historical earthquakes, but knowledge of active faults and source parameters is relatively poor, particularly for seismogenic structures extending offshore. We analysed the fine structure of major tectonic features likely to have been sources of past earthquakes: (i) the NNW–SSE trending Malta STEP (Slab Transfer Edge Propagator) fault system, representing a lateral tear of the subduction system; (ii) the out-of-sequence thrusts (splay faults) at the rear of the salt-bearing Messinian accretionary wedge; and (iii) the Messina Straits fault system, part of the wide deformation zone separating the western and eastern lobes of the accretionary wedge. Our findings have implications for seismic hazard in southern Italy, as we compile an inventory of first order active faults that may have produced past seismic events such as the 1908, 1693 and 1169 earthquakes. These faults are likely to be source regions for future large magnitude events as they are long, deep and bound sectors of the margin characterized by different deformation and coupling rates on the plate interface.

Description: Characteristics of damage to buildings by debris flows on 7 August 2010 in Zhouqu, Western China Natural Hazards and Earth System Science, 12, 2209-2217, 2012 Author(s): K. H. Hu, P. Cui, and J. Q. Zhang A debris-flow catastrophe hit the city of Zhouqu, Gansu Province, western China, at midnight on 7 August 2010 following a local extreme rainfall of 77.3 mm h −1 in the Sanyanyu and Luojiayu ravines, which are located to the north of the urban area. Eight buildings damaged in the event were investigated in detail to study the characteristics and patterns of damage to buildings by debris flows. It was found that major structural damage was caused by the frontal impact of proximal debris flows, while non-structural damage was caused by lateral accumulation and abrasion of sediment. The impact had a boundary decreasing effect when debris flows encountered a series of obstacles, and the inter-positioning of buildings produced so-called back shielding effects on the damage. Impact, accumulation, and abrasion were the three main patterns of damage to buildings in this event. The damage scale depended not only on the flow properties, such as density, velocity, and depth, but also on the structural strength of buildings, material, orientation, and geometry. Reinforced concrete-framed structures can effectively resist a much higher debris-flow impact than brick-concrete structures. With respect to the two typical types of structure, a classification scheme to assess building damage is proposed by referring to the Chinese Classification System of Earthquake Damage to Buildings. Furthermore, three damage scales (major structural, minor structural, and non-structural damage) are defined by critical values of impact pressure. Finally, five countermeasures for effectively mitigating the damage are proposed according to the on-site investigation.

Description: Enhancing flood resilience through improved risk communications Natural Hazards and Earth System Science, 12, 2271-2282, 2012 Author(s): J. J. O'Sullivan, R. A. Bradford, M. Bonaiuto, S. De Dominicis, P. Rotko, J. Aaltonen, K. Waylen, and S. J. Langan A framework of guiding recommendations for effective pre-flood and flood warning communications derived from the URFlood project (2nd ERA-Net CRUE Research Funding Initiative) from extensive quantitative and qualitative research in Finland, Ireland, Italy and Scotland is presented. Eleven case studies in fluvial, pluvial, coastal, residual and "new" flood risk locations were undertaken. The recommendations were developed from questionnaire surveys by exploring statistical correlations of actions and understandings of individuals in flood risk situations to low, moderate and high resilience groupings. Groupings were based on a conceptual relationship of self-assessed levels of awareness, preparedness and worry. Focus groups and structured interviews were used to discuss barriers in flood communications, explore implementation of the recommendations and to rank the recommendations in order of perceived importance. Results indicate that the information deficit model for flood communications that relies on the provision of more and better information to mitigate risk in flood-prone areas is insufficient, and that the communications process is very much multi-dimensional. The recommendations are aimed at addressing this complexity and their careful implementation is likely to improve the penetration of flood communications. The recommendations are applicable to other risks and are transferrable to jurisdictions beyond the project countries.

Description: Assessment of coastal vulnerability to climate change hazards at the regional scale: the case study of the North Adriatic Sea Natural Hazards and Earth System Science, 12, 2347-2368, 2012 Author(s): S. Torresan, A. Critto, J. Rizzi, and A. Marcomini Sea level rise, changes in storms and wave climate as a consequence of global climate change are expected to increase the size and magnitude of flooded and eroding coastal areas, thus having profound impacts on coastal communities and ecosystems. River deltas, beaches, estuaries and lagoons are considered particularly vulnerable to the adverse effects of climate change, which should be studied at the regional/local scale. This paper presents a regional vulnerability assessment (RVA) methodology developed to analyse site-specific spatial information on coastal vulnerability to the envisaged effects of global climate change, and assist coastal communities in operational coastal management and conservation. The main aim of the RVA is to identify key vulnerable receptors (i.e. natural and human ecosystems) in the considered region and localize vulnerable hot spot areas, which could be considered as homogeneous geographic sites for the definition of adaptation strategies. The application of the RVA methodology is based on a heterogeneous subset of bio-geophysical and socio-economic vulnerability indicators (e.g. coastal topography, geomorphology, presence and distribution of vegetation cover, location of artificial protection), which are a measure of the potential harm from a range of climate-related impacts (e.g. sea level rise inundation, storm surge flooding, coastal erosion). Based on a system of numerical weights and scores, the RVA provides relative vulnerability maps that allow to prioritize more vulnerable areas and targets of different climate-related impacts in the examined region and to support the identification of suitable areas for human settlements, infrastructures and economic activities, providing a basis for coastal zoning and land use planning. The implementation, performance and results of the methodology for the coastal area of the North Adriatic Sea (Italy) are fully described in the paper.

Description: Impacts of soil and groundwater salinization on tree crop performance in post-tsunami Aceh Barat, Indonesia Natural Hazards and Earth System Science, 12, 2879-2891, 2012 Author(s): C. Marohn, A. Distel, G. Dercon, Wahyunto, R. Tomlinson, M. v. Noordwijk, and G. Cadisch The Indian Ocean tsunami of December 2004 had far reaching consequences for agriculture in Aceh province, Indonesia, and particularly in Aceh Barat district, 150 km from the seaquake epicentre. In this study, the spatial distribution and temporal dynamics of soil and groundwater salinity and their impact on tree crops were monitored in Aceh Barat from 2006 to 2008. On 48 sampling points along ten transects, covering 40 km of coastline, soil and groundwater salinity were measured and related to mortality and yield depression of the locally most important tree crops. Given a yearly rainfall of over 3000 mm, initial groundwater salinity declined rapidly from over 10 to less than 2 mS cm −1 within two years. On the other hand, seasonal dynamics of the groundwater table in combination with intrusion of saline water into the groundwater body led to recurring elevated salinity, sufficient to affect crops. Tree mortality and yield depression in the flooded area varied considerably between tree species. Damage to coconut (65% trees damaged) was related to tsunami run-up height, while rubber (50% trees damaged) was mainly affected by groundwater salinity. Coconut yields (−35% in average) were constrained by groundwater Ca 2+ and Mg 2+ , while rubber yields (−65% on average) were related to groundwater chloride, pH and soil sodium. These findings have implications on planting deep-rooted tree crops as growth will be constrained by ongoing oscillations of the groundwater table and salinity.

Description: Automated detection of snow avalanche deposits: segmentation and classification of optical remote sensing imagery Natural Hazards and Earth System Science, 12, 2893-2906, 2012 Author(s): M. J. Lato, R. Frauenfelder, and Y. Bühler Snow avalanches in mountainous areas pose a significant threat to infrastructure (roads, railways, energy transmission corridors), personal property (homes) and recreational areas as well as for lives of people living and moving in alpine terrain. The impacts of snow avalanches range from delays and financial loss through road and railway closures, destruction of property and infrastructure, to loss of life. Avalanche warnings today are mainly based on meteorological information, snow pack information, field observations, historically recorded avalanche events as well as experience and expert knowledge. The ability to automatically identify snow avalanches using Very High Resolution (VHR) optical remote sensing imagery has the potential to assist in the development of accurate, spatially widespread, detailed maps of zones prone to avalanches as well as to build up data bases of past avalanche events in poorly accessible regions. This would provide decision makers with improved knowledge of the frequency and size distributions of avalanches in such areas. We used an object–oriented image interpretation approach, which employs segmentation and classification methodologies, to detect recent snow avalanche deposits within VHR panchromatic optical remote sensing imagery. This produces avalanche deposit maps, which can be integrated with other spatial mapping and terrain data. The object-oriented approach has been tested and validated against manually generated maps in which avalanches are visually recognized and digitized. The accuracy (both users and producers) are over 0.9 with errors of commission less than 0.05. Future research is directed to widespread testing of the algorithm on data generated by various sensors and improvement of the algorithm in high noise regions as well as the mapping of avalanche paths alongside their deposits.

Description: An integrated approach to the study of catastrophic debris-flows: geological hazard and human influence Natural Hazards and Earth System Science, 12, 2907-2922, 2012 Author(s): C. Del Ventisette, F. Garfagnoli, A. Ciampalini, A. Battistini, G. Gigli, S. Moretti, and N. Casagli On 1 October 2009, a prolonged and intense rainstorm triggered hundreds of landslides (predominantly debris flows) in an area of about 50 km 2 in the north-eastern sector of Sicily (Italy). Debris flows swept the highest parts of many villages and passed over the SS114 state highway and the Messina-Catania railway, causing more than 30 fatalities. This region has a high relief, due to recent uplift. The peculiar geological and geomorphological framework represents one of the most common predisposing causes of rainstorm-triggered debris flows. This paper deals with the geological and hydro-geomorphological studies performed as a part of the post-disaster activities operated in collaboration with Civil Protection Authority, with the aim at examining landslides effects and mechanisms. The data were elaborated into a GIS platform, to evaluate the influence of urbanisation on the drainage pattern, and were correlated with the lithological and structural framework of the area. Our study points at the evaluation of the volume involved, the detection of triggering mechanisms and the precise reconstruction of the influence of urbanisation as fundamental tools for understanding the dynamics of catastrophic landslides. This kind of analysis, including all the desirable approaches for the correct management of debris flow should be the starting point for robust urban planning.

Description: Improving the active involvement of stakeholders and the public in flood risk management – tools of an involvement strategy and case study results from Austria, Germany and Italy Natural Hazards and Earth System Science, 12, 2785-2798, 2012 Author(s): M. Fleischhauer, S. Greiving, F. Flex, M. Scheibel, T. Stickler, N. Sereinig, G. Koboltschnig, P. Malvati, V. Vitale, P. Grifoni, and K. Firus The EU Flood Risk Management Directive 2007/60/EC aims at an active involvement of interested parties in the setting up of flood risk management plans and thus calls for more governance-related decision-making. This requirement has two perspectives. On the one hand, there is (1) the question of how decision-makers can improve the quality of their governance process. On the other hand, there is (2) the question of how the public shall be appropriately informed and involved. These questions were the centre of the ERA-Net CRUE-funded project IMRA (integrative flood risk governance approach for improvement of risk awareness) that aimed at an optimisation of the flood risk management process by increasing procedural efficiency with an explicit involvement strategy. To reach this goal, the IMRA project partners developed two new approaches that were implemented in three case study areas for the first time in flood risk management: 1. risk governance assessment tool: An indicator-based benchmarking and monitoring tool was used to evaluate the performance of a flood risk management system in regard to ideal risk governance principles; 2. social milieu approach: The concept of social milieus was used to gain a picture of the people living in the case study regions to learn more about their lifestyles, attitudes and values and to use this knowledge to plan custom-made information and participation activities for the broad public. This paper presents basic elements and the application of two innovative approaches as a part of an "involvement strategy" that aims at the active involvement of all interested parties (stakeholders) for assessing, reviewing and updating flood risk management plans, as formulated in the EU Flood Risk Management Directive 2007/60/EC.

Description: The CASA quantitative precipitation estimation system: a five year validation study Natural Hazards and Earth System Science, 12, 2811-2820, 2012 Author(s): V. Chandrasekar, Y. Wang, and H. Chen Flooding is one of the most common natural hazards that produce substantial loss of life and property. The QPE products that are derived at high spatiotemporal resolution, which is enabled by the deployment of a dense radar network, have the potential to improve the prediction of flash-flooding threats when coupled with hydrological models. The US National Science Foundation Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) is dedicated to revolutionizing our ability to observe, understand, predict, and respond to hazardous weather events, especially in the lower atmosphere. CASA's technology enables precipitation observation close to the ground and QPE is one of the important products generated by the system. This paper describes the CASA QPE system built on the various underlying technologies of networked X-band radar systems providing high-resolution (in space and time) measurements, using the rainfall products from the radar. Evaluation of the networked rainfall product using 5 yr of data from the CASA IP-1 test bed is presented. Cross validation of the product using 5 yr of data with a gauge network is also provided. The validation shows the excellent performance of the CASA QPE system with a standard error of 25% and a low bias of 3.7%. Examples of various CASA rainfall products including instantaneous and hourly rainfall accumulations are shown.

Description: Daily precipitation concentration across Europe 1971–2010 Natural Hazards and Earth System Science, 12, 2799-2810, 2012 Author(s): N. Cortesi, J. C. Gonzalez-Hidalgo, M. Brunetti, and J. Martin-Vide Daily Precipitation Concentration Index (CI) was used in this paper to investigate the statistical structure of daily precipitation across Europe based on 530 daily rainfall series for the period 1971–2010. Annual CI shows a North-West to South-East gradient (excluding Turkey and Greece). The same gradient is also observed in winter, spring and autumn, while in summer the gradient is North-South. Highest annual and seasonal daily concentrations of rainfall were detected in the western Mediterranean basin, mainly along Spanish and French coastlands. Latitude and distance from the sea seems to play a major role on spatial CI distribution; at subregional scale also relief plays an important role. The Mann–Kendall test did not identify uniform significant pattern in temporal trend across Europe for 1971–2010 period. The only broad areas with increasing annual and seasonal CI values are located in northern and south-western France and northern coastlands of the Iberian Peninsula. This findings suggest that daily precipitation distribution has not significantly changed during the 1971–2010 over Europe.

Description: Collaborative modelling for active involvement of stakeholders in urban flood risk management Natural Hazards and Earth System Science, 12, 2821-2842, 2012 Author(s): M. Evers, A. Jonoski, Č. Maksimovič, L. Lange, S. Ochoa Rodriguez, A. Teklesadik, J. Cortes Arevalo, A. Almoradie, N. Eduardo Simões, L. Wang, and C. Makropoulos This paper presents an approach to enhance the role of local stakeholders in dealing with urban floods. The concept is based on the DIANE-CM project (Decentralised Integrated Analysis and Enhancement of Awareness through Collaborative Modelling and Management of Flood Risk) of the 2nd ERANET CRUE funding initiative. The main objective of the project was to develop and test an advanced methodology for enhancing the resilience of local communities to flooding. Through collaborative modelling, a social learning process was initiated that enhances the social capacity of the stakeholders due to the interaction process. The other aim of the project was to better understand how data from hazard and vulnerability analyses and improved maps, as well as from the near real-time flood prediction, can be used to initiate a public dialogue (i.e. collaborative mapping and planning activities) in order to carry out more informed and shared decision-making processes and to enhance flood risk awareness. The concept of collaborative modelling was applied in two case studies: (1) the Cranbrook catchment in the UK, with focus on pluvial flooding; and (2) the Alster catchment in Germany, with focus on fluvial flooding. As a result of the interactive and social learning process, supported by sociotechnical instruments, an understanding of flood risk was developed amongst the stakeholders and alternatives for flood risk management for the respective case study area were jointly developed and ranked as a basis for further planning and management.

Description: A quantitative flood risk analysis methodology for urban areas with integration of social research data Natural Hazards and Earth System Science, 12, 2843-2863, 2012 Author(s): I. Escuder-Bueno, J. T. Castillo-Rodríguez, S. Zechner, C. Jöbstl, S. Perales-Momparler, and G. Petaccia Risk analysis has become a top priority for authorities and stakeholders in many European countries, with the aim of reducing flooding risk, considering the population's needs and improving risk awareness. Within this context, two methodological pieces have been developed in the period 2009–2011 within the SUFRI project (Sustainable Strategies of Urban Flood Risk Management with non-structural measures to cope with the residual risk, 2nd ERA-Net CRUE Funding Initiative). First, the "SUFRI Methodology for pluvial and river flooding risk assessment in urban areas to inform decision-making" provides a comprehensive and quantitative tool for flood risk analysis. Second, the "Methodology for investigation of risk awareness of the population concerned" presents the basis to estimate current risk from a social perspective and identify tendencies in the way floods are understood by citizens. Outcomes of both methods are integrated in this paper with the aim of informing decision making on non-structural protection measures. The results of two case studies are shown to illustrate practical applications of this developed approach. The main advantage of applying the methodology herein presented consists in providing a quantitative estimation of flooding risk before and after investing in non-structural risk mitigation measures. It can be of great interest for decision makers as it provides rational and solid information.

Description: Damage estimation of subterranean building constructions due to groundwater inundation – the GIS-based model approach GRUWAD Natural Hazards and Earth System Science, 12, 2865-2877, 2012 Author(s): R. Schinke, M. Neubert, J. Hennersdorf, U. Stodolny, T. Sommer, and T. Naumann The analysis and management of flood risk commonly focuses on surface water floods, because these types are often associated with high economic losses due to damage to buildings and settlements. The rising groundwater as a secondary effect of these floods induces additional damage, particularly in the basements of buildings. Mostly, these losses remain underestimated, because they are difficult to assess, especially for the entire building stock of flood-prone urban areas. For this purpose an appropriate methodology has been developed and lead to a groundwater damage simulation model named GRUWAD. The overall methodology combines various engineering and geoinformatic methods to calculate major damage processes by high groundwater levels. It considers a classification of buildings by building types, synthetic depth-damage functions for groundwater inundation as well as the results of a groundwater-flow model. The modular structure of this procedure can be adapted in the level of detail. Hence, the model allows damage calculations from the local to the regional scale. Among others it can be used to prepare risk maps, for ex-ante analysis of future risks, and to simulate the effects of mitigation measures. Therefore, the model is a multifarious tool for determining urban resilience with respect to high groundwater levels.

Description: Review Article: "Adaptive governance and resilience: the role of multi-stakeholder platforms in disaster risk reduction" Natural Hazards and Earth System Science, 12, 2923-2942, 2012 Author(s): R. Djalante Disaster impacts are more frequent, deadly and costly. The social and environmental consequences are increasingly complex and intertwined. Systematic as well as innovated strategies are needed to manage the impacts. Disaster Risk Reduction (DRR) is a systematic approach to manage disaster risks while adaptive governance (AG) is suggested as an alternative approach for governing complex problems such as disasters. The author proposes that the AG can be practicalised through a mechanism of multi-stakeholder platforms (MSPs), interpreted as multiplicity of organisations at different scales of governance working towards more coordinated and integrated actions in DRR. Ten MSPs are selected at the global, regional, national and local level, focussing on the Indonesian MSPs. The literature reviews and in-depth interviews with key respondents in Indonesia show that the international and regional MSPs tend to have more human, technical and financial capacity than national and local MSPs. The author finds that most MSP roles focus on the coordination amongst multitudes of organisations. Only those MSPs that are able to generate new funding have the capacity to implement direct risk reduction activities. The development of the MSP is highly influenced by the UNISDR system operating at different levels. Particularly in Indonesia, MSP are also influenced by the operations of various UN and international organisations. Finally, the paper suggests the need for more provision of technical supports to local MSPs, more linkages with established networks in DRR and broader stakeholders involvement within the MSPs.

Description: Long-term temporal changes in the occurrence of a high forest fire danger in Finland Natural Hazards and Earth System Science, 12, 2591-2601, 2012 Author(s): H. M. Mäkelä, M. Laapas, and A. Venäläinen Climate variation and change influence several ecosystem components including forest fires. To examine long-term temporal variations of forest fire danger, a fire danger day (FDD) model was developed. Using mean temperature and total precipitation of the Finnish wildfire season (June–August), the model describes the climatological preconditions of fire occurrence and gives the number of fire danger days during the same time period. The performance of the model varied between different regions in Finland being best in south and west. In the study period 1908–2011, the year-to-year variation of FDD was large and no significant increasing or decreasing tendencies could be found. Negative slopes of linear regression lines for FDD could be explained by the simultaneous, mostly not significant increases in precipitation. Years with the largest wildfires did not stand out from the FDD time series. This indicates that intra-seasonal variations of FDD enable occurrence of large-scale fires, despite the whole season's fire danger is on an average level. Based on available monthly climate data, it is possible to estimate the general fire conditions of a summer. However, more detailed input data about weather conditions, land use, prevailing forestry conventions and socio-economical factors would be needed to gain more specific information about a season's fire risk.

Description: Testing the critical exponent in the relation between stress drop of earthquake and lead time of seismic electric signal Natural Hazards and Earth System Science, 12, 2603-2607, 2012 Author(s): E. Dologlou The application of new data in the power law relation between the stress drop of the earthquake and the lead time of the precursory seismic electric signal led to an exponent which falls in the range of the values of critical exponents for fracture and it is in excellent agreement with a previous one found by (Dologlou, 2012). In addition, this exponent is very close to the one reported by Varotsos and Alexopoulos (1984a), which interconnects the amplitude of the precursory seismic electric signals (SES) and the magnitude of the impending earthquake. Hence, the hypothesis that underlying dynamic processes evolving to criticality prevail in the pre-focal area when the SES is emitted is significantly supported.

Description: Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian Ocean Natural Hazards and Earth System Science, 12, 2609-2630, 2012 Author(s): J. M. Schwab, S. Krastel, M. Grün, F. Gross, P. Pananont, P. Jintasaeranee, S. Bunsomboonsakul, W. Weinrebe, and D. Winkelmann 2-D seismic data from the top and the western slope of Mergui Ridge in water depths between 300 and 2200 m off the Thai west coast have been investigated in order to identify mass transport deposits (MTDs) and evaluate the tsunamigenic potential of submarine landslides in this outer shelf area. Based on our newly collected data, 17 mass transport deposits have been identified. Minimum volumes of individual MTDs range between 0.3 km 3 and 14 km 3 . Landslide deposits have been identified in three different settings: (i) stacked MTDs within disturbed and faulted basin sediments at the transition of the East Andaman Basin to the Mergui Ridge; (ii) MTDs within a pile of drift sediments at the basin-ridge transition; and (iii) MTDs near the edge of/on top of Mergui Ridge in relatively shallow water depths ( 〈 1000 m). Our data indicate that the Mergui Ridge slope area seems to have been generally unstable with repeated occurrence of slide events. We find that the most likely causes for slope instabilities may be the presence of unstable drift sediments, excess pore pressure, and active tectonics. Most MTDs are located in large water depths (〉 1000 m) and/or comprise small volumes suggesting a small tsunami potential. Moreover, the recurrence rates of failure events seem to be low. Some MTDs with tsunami potential, however, have been identified on top of Mergui Ridge. Mass-wasting events that may occur in the future at similar locations may trigger tsunamis if they comprise sufficient volumes. Landslide tsunamis, emerging from slope failures in the working area and affecting western Thailand coastal areas therefore cannot be excluded, though the probability is very small compared to the probability of earthquake-triggered tsunamis, arising from the Sunda Trench.

Description: Instability mechanisms affecting cultural heritage sites in the Maltese Archipelago Natural Hazards and Earth System Science, 12, 1883-1903, 2012 Author(s): G. Gigli, W. Frodella, F. Mugnai, D. Tapete, F. Cigna, R. Fanti, E. Intrieri, and L. Lombardi The superimposition of geological formations with marked contrast in geotechnical properties presents one of the most critical environments for slope instability due to the different response of the materials to the applied disturbances. Moreover, the above-mentioned geological setting is often associated with high risk conditions, since many isolated rock slabs located at a higher altitude than the surrounding countryside have been sites of historical towns or buildings. The purpose of the present paper is to investigate the mechanisms determining instability in rock slabs overlying a soft substratum, with reference to two cultural heritage sites in Malta. Accurate investigations have been carried out to evaluate the geological, geotechnical and geomechanical properties together with the main geomorphological features of the soft clayey substratum and the overlying limestone rock mass. The main instability processes have thus been identified and investigated through kinematic analyses and numerical modeling, combined with a 1992–2001 Persistent Scatterers monitoring of ground displacements. The study constitutes the basis for the subsequent restoration works.

Description: Investigation of the temporal fluctuations of the 1960–2010 seismicity of Caucasus Natural Hazards and Earth System Science, 12, 1905-1909, 2012 Author(s): L. Telesca, T. Matcharashvili, and T. Chelidze The time-clustering behaviour of the seismicity of the Caucasus spanning from 1960 to 2010 was investigated. The analysis was performed on the whole and aftershock-depleted catalogues by means of the method of Allan Factor, which permits the identification and quantification of time-clustering in point processes. The whole sequence is featured by two scaling regimes with the scaling exponent at intermediate timescales lower than that at high timescales, and a crossover that could be probably linked with aftershock time activiation. The aftershock-depleted sequence is characterized by higher time-clustering degree and the presence of a periodicity probably correlated with the cyclic earth surface load variations on regional and local scales, e.g. with snow melting in Caucasian mountains and large Enguri dam operations. The obtained results were corroborated by the application of two surrogate methods: the random shuffling and the generation of Poissonian sequences.

Description: Impact of heat and drought stress on arable crop production in Belgium Natural Hazards and Earth System Science, 12, 1911-1922, 2012 Author(s): A. Gobin Modelling approaches are needed to accelerate understanding of adverse weather impacts on crop performances and yields. The aim was to elicit biometeorological conditions that affect Belgian arable crop yield, commensurate with the scale of climatic impacts. The regional crop model REGCROP (Gobin, 2010) enabled to examine changing weather patterns in relation to the crop season and crop sensitive stages of six arable crops: winter wheat, winter barley, winter rapeseed, potato, sugar beet and maize. The sum of vapour pressure deficit during the growing season is the single best predictor of arable yields, with R 2 ranging from 0.55 for sugar beet to 0.76 for wheat. Drought and heat stress, in particular during the sensitive crop stages, occur at different times in the crop season and significantly differ between two climatic periods, 1947–1987 and 1988–2008. Though average yields have risen steadily between 1947 and 2008, there is no evidence that relative tolerance to stress has improved.

Description: ICT approaches to integrating institutional and non-institutional data services for better understanding of hydro-meteorological phenomena Natural Hazards and Earth System Science, 12, 1961-1968, 2012 Author(s): T. Bedrina, A. Parodi, A. Quarati, and A. Clematis It is widely recognised that an effective exploitation of Information and Communication Technologies (ICT) is an enabling factor to achieve major advancements in Hydro-Meteorological Research (HMR). Recently, a lot of attention has been devoted to the use of ICT in HMR activities, e.g. in order to facilitate data exchange and integration, to improve computational capabilities and consequently model resolution and quality. Nowadays, ICT technologies have demonstrated that it is possible to extend monitoring networks by integrating sensors and other sources of data managed by volunteer's communities. These networks are constituted by peers that span a wide portion of the territory in many countries. The peers are "location aware" in the sense that they provide information strictly related with their geospatial location. The coverage of these networks, in general, is not uniform and the location of peers may follow random distribution. The ICT features used to set up the network are lightweight and user friendly, thus, permitting the peers to join the network without the necessity of specialised ICT knowledge. In this perspective it is of increasing interest for HMR activities to elaborate of Personal Weather Station (PWS) networks, capable to provide almost real-time, location aware, weather data. Moreover, different big players of the web arena are now providing world-wide backbones, suitable to present on detailed map location aware information, obtained by mashing up data from different sources. This is the case, for example, with Google Earth and Google Maps. This paper presents the design of a mashup application aimed at aggregating, refining and visualizing near real-time hydro-meteorological datasets. In particular, we focused on the integration of instant precipitation depths, registered either by widespread semi-professional weather stations and official ones. This sort of information has high importance and usefulness in decision support systems and Civil Protection applications. As a significant case study, we analysed the rainfall data observed during the severe flash-flood event of 4 November 2011 over Liguria region, Italy. The joint use of official observation network with PWS networks and meteorological radar allowed for the making of evident finger-like convection structure.

Description: Review article "Remarks on factors influencing shear wave velocities and their role in evaluating susceptibilities to earthquake-triggered slope instability: case study for the Campania area (Italy)" Natural Hazards and Earth System Science, 12, 2147-2158, 2012 Author(s): V. Paoletti Shear wave velocities have a fundamental role in connection with the mitigation of seismic hazards, as their low values are the main causes of site amplification phenomena and can significantly influence the susceptibility of a territory to seismic-induced landslides. The shear wave velocity (Vs) and modulus ( G ) of each lithological unit are influenced by factors such as the degree of fracturing and faulting, the porosity, the clay amount and the precipitation, with the latter two influencing the unit water content. In this paper we discuss how these factors can affect the Vs values and report the results of different analyses that quantify the reduction in the rock Vs and shear modulus values connected to the presence of clay and water. We also show that significant results in assessing seismic-induced slope failure susceptibility for land planning targets could be achieved through a careful evaluation, based only on literature studies, of the geo-lithological and geo-seismic features of the study area.

Description: Corrigendum to "Probabilistic sensitivity analysis of two suspension bridges in Istanbul, Turkey to near- and far-fault ground motion" published in Nat. Hazards Earth Syst. Sci., 12, 459–473, 2012 Natural Hazards and Earth System Science, 12, 2173-2175, 2012 Author(s): Ö. Çavdar No abstract available.

Description: The identity approach for assessing socio-technical resilience to climate change: example of flood risk management for the Island of Dordrecht Natural Hazards and Earth System Science, 12, 2139-2146, 2012 Author(s): B. Gersonius, R. Ashley, and C. Zevenbergen Recent EU guidance on adaptation calls for the enhancement of socio-technical resilience to climate change. However, socio-technical resilience is relatively poorly defined and this makes it difficult to apply in practice. This paper uses the concept of identity as a vehicle to advance the definition and assessment of socio-technical resilience. Identity comprises four aspects (components, relationships, innovation, and continuity) that constitute the minimum of what has to be identified and specified if resilience is to be assessed. Characterising the identity of a socio-technical system requires the conceptualisation of these four aspects in relation to the particular function provided by the system (e.g. flood risk management) and also the identification of the specific variables and thresholds that reflect changes in identity. We have demonstrated the utility of the identity approach, using the example of flood risk management for the Island of Dordrecht, the Netherlands. Based on the results, socio-technical resilience has been redefined as the ability of the system to continue to function as expected in the face of change. This definition implies that a system is resilient when it can deliver performance without a change of identity by continuing compliance with standards and expectations.

Description: Change of extreme rainfall indexes at Ebro River Basin Natural Hazards and Earth System Science, 12, 2127-2137, 2012 Author(s): J. L. Valencia, A. M. Tarquis, A. Saá-Requejo, and J. M. Gascó Extreme rainfall events are a serious concern for regional hydrology and agriculture in the Ebro River Basin. Repeated anomalous rainfall in recent decades has had a devastating impact on this region, both socially and economically. Some studies developed in Italy and USA have shown that there is a change in seasonal patterns and an increasing frequency of extreme rainfall events, whereas other studies have pointed out that no global behaviour could be observed in monthly trends due to high climatic variability. The aim of this work is to test which of these scenarios is the case for the Ebro River Basin. For this purpose, 14 meteorological stations were selected based on the length of the rainfall series and the climatic classification to obtain a representative untreated dataset from the river basin. Daily rainfall series from 1957 to 2002 were obtained from each meteorological station. First, classical climatic indexes were analysed with an autoregressive test to study possible trends in rainfall. The results can be explained following the evolution of the NAO and WeMO indexes, which indicate that the initial period should be subdivided in two periods (1957–1979 and 1980–2002) to assume stationarity and to analyse the rainfall distribution functions. The general results obtained in this study for both sub-periods, through the generalised Pareto distribution (GPD) parameters and the maximum expected return values, do not support the results previously obtained by other authors that affirm a positive trend in extreme rainfall indexes and point to a slight reduction indicated by others. Three extreme precipitation indexes show negative statistical significant trends. GPD-scale parameters decrease except for only one rain gauge, although this decrease is only statistically significant for two rain gauges. Another two locations show statistical significance decreased for maximum expected return values.

Description: Searching for the seafloor signature of the 21 May 2003 Boumerdès earthquake offshore central Algeria Natural Hazards and Earth System Science, 12, 2159-2172, 2012 Author(s): A. Cattaneo, N. Babonneau, G. Ratzov, G. Dan-Unterseh, K. Yelles, R. Bracène, B. Mercier de Lépinay, A. Boudiaf, and J. Déverchère Shaking by moderate to large earthquakes in the Mediterranean Sea has proved in the past to potentially trigger catastrophic sediment collapse and flow. On 21 May 2003, a magnitude 6.8 earthquake located near Boumerdès (central Algerian coast) triggered large turbidity currents responsible for 29 submarine cable breaks at the foot of the continental slope over ~150 km from west to east. Seafloor bathymetry and backscatter imagery show the potential imprints of the 2003 event and of previous events. Large slope scarps resulting from active deformation may locally enhance sediment instabilities, although faults are not directly visible at the seafloor. Erosion is evident at the foot of the margin and along the paths of the numerous canyons and valleys. Cable breaks are located at the outlets of submarine valleys and in areas of turbiditic levee overspilling and demonstrate the multi-source and multi-path character of the 2003 turbiditic event. Rough estimates of turbidity flow velocity are not straightforward because of the multiple breaks along the same cable, but seem compatible with those measured in other submarine cable break studies elsewhere. While the signature of the turbidity currents is mostly erosional on the continental slope, turbidite beds alternating with hemipelagites accumulate in the distal reaches of sediment dispersal systems. In perspective, more chronological work on distal turbidite successions offshore Algeria offers promising perspectives for paleoseismology reconstructions based on turbidite dating, if synchronous turbidites along independent sedimentary dispersal systems are found to support triggering by major earthquakes. Preliminary results on sediment core PSM-KS23 off Boumerdès typically show a 800-yr interval between turbidites during the Holocene, in accordance with the estimated mean seismic cycle on land, even if at this stage it is not yet possible to prove the earthquake origin of all the turbidites.

Description: The influence of Alpine soil properties on shallow movement hazards, investigated through factor analysis Natural Hazards and Earth System Science, 12, 1845-1854, 2012 Author(s): S. Stanchi, M. Freppaz, and E. Zanini Mountain watersheds are particularly vulnerable to extreme meteorological events, such as high intensity rainfall, and mountain soils often show pronounced fragility and low resilience due to severe environmental conditions. Alpine soil vulnerability is partly intrinsic but in part related to climate change (mainly precipitation regimes), and is enhanced by the abandonment of rural mountain areas that reduced the land maintenance actions traditionally carried out by farmers and local populations in the past. Soil hazards are related to different processes such as water erosion, loss of consistency, surface runoff and sediment transport, often occurring simultaneously and interacting with each other. Therefore, the overall effects on soil are not easy to quantify as they can be evaluated from different soil chemical and physical properties, referring to specific soil loss phenomena such as soil erosion, soil liquefaction, loss of consistency etc. In this study, we focus our attention on a mountain region in the NW Italian Alps (Valle d'Aosta), which suffered from diffuse soil instability phenomena in recent years, as a consequence of extreme rainfall events and general abandonment of the agricultural activities in marginal areas. The main effects were a large number of shallow landislides involving limited soil depths (less than 1 m), affecting considerable surfaces in the lower and middle part of the slopes. These events caused loss of human lives in the year 2000 and therefore raised the attention on land maintenance issues. Surface (topsoil: 0–20 cm) and subsurface (subsoil: 20–70 cm) samples were characterised chemically and physically (pH, carbon and nitrogen contents, cation exchange capacity, texture, aggregate stability, Atterberg limits etc.) and they showed very different soil properties. Topsoils were characterised by better stability, structure, and consistency. The differences between the two depths were potential trigger factors for shallow soil movements involving the upper soil horizons. We assessed a great number of soil properties that are known to be related to vulnerability to the main hazards present in the area. These properties were evaluated at the two depths and a factor analysis was performed to simplify the dataset interpretation, and to hypothesise the most decisive parameters that were potentially related to vulnerability. The factors (soil structure, aggregation, consistency, texture and parent material, cation exchange complex and other chemical properties) were a first step towards identifying soil quality indexes in the studied environment.

Description: Logistic regression applied to natural hazards: rare event logistic regression with replications Natural Hazards and Earth System Science, 12, 1937-1947, 2012 Author(s): M. Guns and V. Vanacker Statistical analysis of natural hazards needs particular attention, as most of these phenomena are rare events. This study shows that the ordinary rare event logistic regression, as it is now commonly used in geomorphologic studies, does not always lead to a robust detection of controlling factors, as the results can be strongly sample-dependent. In this paper, we introduce some concepts of Monte Carlo simulations in rare event logistic regression. This technique, so-called rare event logistic regression with replications, combines the strength of probabilistic and statistical methods, and allows overcoming some of the limitations of previous developments through robust variable selection. This technique was here developed for the analyses of landslide controlling factors, but the concept is widely applicable for statistical analyses of natural hazards.

Description: The educational and awareness purposes of the Paideia approach for heritage management Natural Hazards and Earth System Science, 12, 1983-1986, 2012 Author(s): F. Carbone, L. Oosterbeek, and C. Costa The need to raise awareness among the communities about the challenge of resource use – and, more generally, about the principles of sustainability – is the reason why the United Nations General Assembly proclaimed, in December 2002, the United Nations Decade of Education for Sustainable Development, 2005–2014 (DESD). For operators and managers of cultural and natural heritage, it represents a profound challenge to their ability to transmit the content of scientific knowledge to the general public in order to empower everyone on the preservation of cultural and natural resources, and to raise awareness about the potential that mankind has at its disposal. In this context, the application of the PAIDEIA APPROACH for the management of cultural heritage is the key to the recovery of socio-economic values intrinsic to these resources. This approach to management is based on the enhancement of cultural (namely archaeological) and natural heritage for social benefit and it involves the tourist trade as a vehicle of knowledge transmission, intercultural dialogue and socio-economic sustainable development.

Description: Quantifying human vulnerability in rural areas: case study of Tutova Hills (Eastern Romania) Natural Hazards and Earth System Science, 12, 1987-2001, 2012 Author(s): I. C. Stângă and A. Grozavu This paper aims to assess the vulnerability at regional level, the model and the proposed indicators being explicitly intended for an essentially rural region, in this case–Tutova Hills (Eastern Romania). Five categories of variables were taken into account to define the vulnerability components: rural habitat, demographic features, agriculture, environmental quality and emergency situations. For each one, five variables were analyzed and ranked based on the level of determination or subordination. In order to ensure the flexibility of the model and to avoid the criteria duplication in assessing vulnerability, only a single indicator of each category was retained and included in analysis: total number of inhabitants, dependency ratio, weight of arable land on slope categories, weight of land under forestry and road accessibility of villages. The selected indicators were mathematically processed in order to maximize their relevance and to unitary express the results in the spread 0–1. Also, values of each indicator were grouped into four classes, corresponding to the level of vulnerability: low, medium, high and very high. A general index was obtained through the integration of vulnerability factors in an equation based on the geometric mean. Spatial analysis was based on features of the MicroImages TNTmips 7.3. software, which allow the vulnerability mapping. This approach argues and states that vulnerability assessment through indicator-based methods can be made only according to the level and scale of analysis and related to natural or human conditions of a region.

Description: Late Holocene landscape change history related to the Alpine Fault determined from drowned forests in Lake Poerua, Westland, New Zealand Natural Hazards and Earth System Science, 12, 2051-2064, 2012 Author(s): R. M. Langridge, R. Basili, L. Basher, and A. P. Wells Lake Poerua is a small, shallow lake that abuts the scarp of the Alpine Fault on the West Coast of New Zealand's South Island. Radiocarbon dates from drowned podocarp trees on the lake floor, a sediment core from a rangefront alluvial fan, and living tree ring ages have been used to deduce the late Holocene history of the lake. Remnant drowned stumps of kahikatea ( Dacrycarpus dacrydioides ) at 1.7–1.9 m water depth yield a preferred time-of-death age at 1766–1807 AD, while a dryland podocarp and kahikatea stumps at 2.4–2.6 m yield preferred time-of-death ages of ca. 1459–1626 AD. These age ranges are matched to, but offset from, the timings of Alpine Fault rupture events at ca. 1717 AD, and either ca. 1615 or 1430 AD. Alluvial fan detritus dated from a core into the toe of a rangefront alluvial fan, at an equivalent depth to the maximum depth of the modern lake (6.7 m), yields a calibrated age of AD 1223–1413. This age is similar to the timing of an earlier Alpine Fault rupture event at ca. 1230 AD ± 50 yr. Kahikatea trees growing on rangefront fans give ages of up to 270 yr, which is consistent with alluvial fan aggradation following the 1717 AD earthquake. The elevation levels of the lake and fan imply a causal and chronological link between lake-level rise and Alpine Fault rupture. The results of this study suggest that the growth of large, coalescing alluvial fans (Dry and Evans Creek fans) originating from landslides within the rangefront of the Alpine Fault and the rise in the level of Lake Poerua may occur within a decade or so of large Alpine Fault earthquakes that rupture adjacent to this area. These rises have in turn drowned lowland forests that fringed the lake. Radiocarbon chronologies built using OxCal show that a series of massive landscape changes beginning with fault rupture, followed by landsliding, fan sedimentation and lake expansion. However, drowned Kahikatea trees may be poor candidates for intimately dating these events, as they may be able to tolerate water for several decades after metre-scale lake level rises have occurred.

Description: Potential of remote sensing techniques for tsunami hazard and vulnerability analysis – a case study from Phang-Nga province, Thailand Natural Hazards and Earth System Science, 12, 2103-2126, 2012 Author(s): H. Römer, P. Willroth, G. Kaiser, A. T. Vafeidis, R. Ludwig, H. Sterr, and J. Revilla Diez Recent tsunami disasters, such as the 2004 Indian Ocean tsunami or the 2011 Japan earthquake and tsunami, have highlighted the need for effective risk management. Remote sensing is a relatively new method for risk analysis, which shows significant potential in conducting spatially explicit risk and vulnerability assessments. In order to explore and discuss the potential and limitations of remote sensing techniques, this paper presents a case study from the tsunami-affected Andaman Sea coast of Thailand. It focuses on a local assessment of tsunami hazard and vulnerability, including the socio-economic and ecological components. High resolution optical data, including IKONOS data and aerial imagery (MFC-3 camera) as well as different digital elevation models, were employed to create basic geo-data including land use and land cover (LULC), building polygons and topographic data sets and to provide input data for the hazard and vulnerability assessment. Results show that the main potential of applying remote sensing techniques and data derives from a synergistic combination with other types of data. In the case of hazard analysis, detailed LULC information and the correction of digital surface models (DSMs) significantly improved the results of inundation modeling. The vulnerability assessment showed that remote sensing can be used to spatially extrapolate field data on socio-economic or ecological vulnerability collected in the field, to regionalize exposure elements and assets and to predict vulnerable areas. Limitations and inaccuracies became evident regarding the assessment of ecological resilience and the statistical prediction of vulnerability components, based on variables derived from remote sensing data.

Description: Building an 18 000-year-long paleo-earthquake record from detailed deep-sea turbidite characterisation in Poverty Bay, New Zealand Natural Hazards and Earth System Science, 12, 2077-2101, 2012 Author(s): H. Pouderoux, G. Lamarche, and J.-N. Proust Two ~20 m-long sedimentary cores collected in two neighbouring mid-slope basins of the Paritu Turbidite System in Poverty Bay, east of New Zealand, show a high concentration of turbidites (5 to 6 turbidites per meter), interlaid with hemipelagites, tephras and a few debrites. Turbidites occur as both stacked and single, and exhibit a range of facies from muddy to sandy turbidites. The age of each turbidite is estimated using the statistical approach developed in the OxCal software from an exceptionally dense set of tephrochronology and radiocarbon ages (~1 age per meter). The age, together with the facies and the petrophysical properties of the sediment (density, magnetic susceptibility and P-wave velocity), allows the correlation of turbidites across the continental slope (1400–2300 m water depth). We identify 73 synchronous turbidites, named basin events, across the two cores between 819 ± 191 and 17 729 ± 701 yr BP. Compositional, foraminiferal and geochemical signatures of the turbidites are used to characterise the source area of the sediment, the origin of the turbidity currents, and their triggering mechanism. Sixty-seven basin events are interpreted as originated from slope failures on the upper continental slope in water depth ranging from 150 to 1200 m. Their earthquake trigger is inferred from the heavily gullied morphology of the source area and the water depth at which slope failures originated. We derive an earthquake mean return time of ~230 yr, with a 90% probability range from 10 to 570 yr. The earthquake chronology indicates cycles of progressive decrease of earthquake return times from ~400 yr to ~150 yr at 0–7 kyr, 8.2–13.5 kyr, 14.7–18 kyr. The two 1.2 kyr-long intervals in between (7–8.2 kyr and 13.5–14.7 kyr) correspond to basin-wide reorganisations with anomalous turbidite deposition (finer deposits and/or non deposition) reflecting the emplacement of two large mass transport deposits much more voluminous than the "classical" earthquake-triggered turbidites. Our results show that the progressive characterisation of a turbidite record from a single sedimentary system can provide a continuous paleo-earthquake history in regions of short historical record and incomplete onland paleo-earthquake evidences. The systematic description of each turbidite enables us to infer the triggering mechanism.

Description: Using an integrated method to estimate watershed sediment yield during heavy rain period: a case study in Hualien County, Taiwan Natural Hazards and Earth System Science, 12, 1949-1960, 2012 Author(s): S. M. Hsu, H. Y. Wen, N. C. Chen, S. Y. Hsu, and S. Y. Chi A comprehensive approach estimating sediment yield from a watershed is needed to develop better measures for mitigating sediment disasters and assessing downstream impacts. In the present study, an attempt has been made to develop an integrated method, considering sediment supplies associated with soil erosion, shallow landslide and debris flow to estimate sediment yield from a debris-flow-prone watershed on a storm event basis. The integrated method is based on the HSPF and TRIGRS models for predicting soil erosion and shallow landslide sediment yield, and the FLO-2D model for calculating debris flow sediment yield. The proposed method was applied to potential debris-flow watersheds located in the Sioulin Township of Hualien County. The available data such as hourly rainfall data, historical streamflow and sediment records as well as event-based landslide inventory maps have been used for model calibration and validation. Results for simulating sediment yield have been confirmed by comparisons of observed data from several typhoon events. The verified method employed a 24-h design hyetograph with the 100-yr return period to simulate sediment yield within the study area. The results revealed that the influence of shallow landslides on sediment supply as compared with soil erosion was significant. The estimate of landslide transport capacity into a main channel indicated the sediment delivery ratio on a typhoon event basis was approximately 38.4%. In addition, a comparison of sediment yields computed from occurrence and non-occurrence of debris flow scenarios showed that the sediment yield from an occurrence condition was found to be increasing at about 14.2 times more than estimated under a non-occurrence condition. This implied watershed sediment hazard induced by debris flow may cause severe consequences.

Description: Influence of the soil-atmosphere exchange on the hydric profile induced in soil-structure system Natural Hazards and Earth System Science, 12, 2039-2049, 2012 Author(s): A. Al Qadad, I. Shahrour, and M. Rouainia Soil-atmosphere exchange leads to a moisture change in the soil. This can cause major damage to engineering structures due to the soil expansion and shrinkage. The soil-atmosphere exchange is related to several parameters, in particular the soil characteristics and climate conditions. The presence of an engineering structure causes a variation of the hydraulic profile in the soil, which can lead to heterogeneous soil movement and consequently to structural damage. This paper presents a coupled numerical model based on the consideration of both water flow in unsaturated soils and soil-atmosphere exchange. After the validation of the model, the paper presents its use for the analysis of the influence of the presence of structures on moisture change induced under climatic conditions recorded in a semi-arid region. Analysis shows that the presence of the structure leads to important change in the moisture distribution, in particular in the vicinity of the structure.

Description: Wave climate of the Adriatic Sea: a future scenario simulation Natural Hazards and Earth System Science, 12, 2065-2076, 2012 Author(s): A. Benetazzo, F. Fedele, S. Carniel, A. Ricchi, E. Bucchignani, and M. Sclavo We present a study on expected wind wave severity changes in the Adriatic Sea for the period 2070–2099 and their impact on extremes. To do so, the phase-averaged spectral wave model SWAN is forced using wind fields computed by the high-resolution regional climate model COSMO-CLM, the climate version of the COSMO meteorological model downscaled from a global climate model running under the IPCC-A1B emission scenario. Namely, the adopted wind fields are given with a horizontal resolution of 14 km and 40 vertical levels, and they are prepared by the Italian Aerospace Research Centre (CIRA). Firstly, in order to infer the wave model accuracy in predicting seasonal variability and extreme events, SWAN results are validated against a control simulation, which covers the period 1965–1994. In particular, numerical predictions of the significant wave height H s are compared against available in-situ data. Further, a statistical analysis is carried out to estimate changes on wave storms and extremes during the simulated periods (control and future scenario simulations). In particular, the generalized Pareto distribution is used to predict changes of storm peak H s for frequent and rare storms in the Adriatic Sea. Finally, Borgman's theory is applied to estimate the spatial pattern of the expected maximum wave height H max during a storm, both for the present climate and that of the future scenario. Results show a future wave climate in the Adriatic Sea milder than the present climate, even though increases of wave severity can occur locally.

Description: Estimation of seismic ground motions using deterministic approach for major cities of Gujarat Natural Hazards and Earth System Science, 12, 2019-2037, 2012 Author(s): J. Shukla and D. Choudhury A deterministic seismic hazard analysis has been carried out for various sites of the major cities (Ahmedabad, Surat, Bhuj, Jamnagar and Junagadh) of the Gujarat region in India to compute the seismic hazard exceeding a certain level in terms of peak ground acceleration (PGA) and to estimate maximum possible PGA at each site at bed rock level. The seismic sources in Gujarat are very uncertain and recurrence intervals of regional large earthquakes are not well defined. Because the instrumental records of India specifically in the Gujarat region are far from being satisfactory for modeling the seismic hazard using the probabilistic approach, an attempt has been made in this study to accomplish it through the deterministic approach. In this regard, all small and large faults of the Gujarat region were evaluated to obtain major fault systems. The empirical relations suggested by earlier researchers for the estimation of maximum magnitude of earthquake motion with various properties of faults like length, surface area, slip rate, etc. have been applied to those faults to obtain the maximum earthquake magnitude. For the analysis, seven different ground motion attenuation relations (GMARs) of strong ground motion have been utilized to calculate the maximum horizontal ground accelerations for each major city of Gujarat. Epistemic uncertainties in the hazard computations are accounted for within a logic-tree framework by considering the controlling parameters like b -value, maximum magnitude and ground motion attenuation relations (GMARs). The corresponding deterministic spectra have been prepared for each major city for the 50th and 84th percentiles of ground motion occurrence. These deterministic spectra are further compared with the specified spectra of Indian design code IS:1893-Part I (2002) to validate them for further practical use. Close examination of the developed spectra reveals that the expected ground motion values become high for the Kachchh region i.e. Bhuj city and moderate in the Mainland Gujarat, i.e. cities of Surat and Ahmedabad. The seismic ground motion level in the Saurashtra is moderate but marginally differs from that as presently specified in IS:1893-Part I (2002). Based on the present study, the recommended PGA values for the cities studied are 0.13 g, 0.15 g, 0.64 g, 0.14 g and 0.2 g for Ahmedabad city, Surat City, Bhuj City, Jamnagar City and Junagadh city, respectively. The prepared spectra can be further used for seismic resistant design of structures within the above major city boundaries of Gujarat to quantify seismic loading on structures.

Description: Rockfall hazard and risk assessment: an example from a high promontory at the historical site of Monemvasia, Greece Natural Hazards and Earth System Science, 12, 1823-1836, 2012 Author(s): H. Saroglou, V. Marinos, P. Marinos, and G. Tsiambaos The paper presents the kinematics of rock instability of a high limestone promontory, where the Monemvasia historical site is situated, in Peloponnese in Southern Greece. The instability phenomena poses a significant threat to the town located at the base of the slope. Rockfall episodes occurred in the past due to the relaxation of the high cliff, whereas significant undermining of the castle frontiers has been observed at the slope crest. The predominant types of instability are of planar, wedge and toppling failure of medium to large blocks. In order to investigate the existing stability conditions and decide upon the protection measures, stability and rockfall analyses were carried out for numerous slope sections under different loading conditions and protection measures were suggested. A rock-fall risk rating system is proposed, which is based on morphological and structural criteria of the rock mass and on vulnerability and consequences. The rating system is applied for individual sections along the slope and a risk map was produced, which depicted areas having different degree of risk against rockfall occurrences.

Description: Urban vulnerability and resilience within the context of climate change Natural Hazards and Earth System Science, 12, 1811-1821, 2012 Author(s): E. Tromeur, R. Ménard, J.-B. Bailly, and C. Soulié Natural hazards, due to climate change, are particularly damaging in urban areas because of interdependencies of their networks. So, urban resilience has to face up to climate risks. The most impacting phenomenon is the urban heat island (UHI) effect. The storage capacity of heat is depending on shapes of buildings, public spaces, spatial organization, transport or even industrial activities. So, adaptive strategies for improving urban climate could be possible in different ways. In the framework of the French project Resilis, this study characterises urban vulnerability and resilience in terms of energy needs of buildings and outside urban comfort according to the IPCC carbon dioxide emission scenarios B2 and A2 for the period 2050–2100 for 10 French cities. The evolutions of four climate indicators in terms of heating and cooling needs and number of hours when the temperature is above 28 °C are then obtained for each city to analyse climate risks and their impacts in urban environment.

Description: Diffusion in periclase by combination of analytical formulas and thermodynamic model Natural Hazards and Earth System Science, 12, 1841-1844, 2012 Author(s): E. Dologlou Analytical formulas for the temperature dependence of elastic constants of MgO combined with a thermodynamic model, which interconnects bulk properties to point defect parameters, can successfully reproduce the self diffusion coefficients of periclase at temperatures representative of the Earth's mantle conditions. Although the calculated diffusion coefficients are estimated from a single measurement and cover a broad range of values (i.e. five orders of magnitude), an almost excellent agreement with the experimental ones is observed. The slight discrepancy at the highest temperature lies at error margins.

Description: Brief communication "Hurricane Irene: a wake-up call for New York City?" Natural Hazards and Earth System Science, 12, 1837-1840, 2012 Author(s): J. C. J. H. Aerts and W. J. W. Botzen The weakening of Irene from a Category 3 hurricane to a tropical storm resulted in less damage in New York City (NYC) than initially was anticipated. It is widely recognized that the storm surge and associated flooding could have been much more severe. In a recent study, we showed that a direct hit to the city from a hurricane may expose an enormous number of people to flooding. A major hurricane has the potential to cause large-scale damage in NYC. The city's resilience to flooding can be increased by improving and integrating flood insurance, flood zoning, and building code policies.

Description: Assessing enigmatic boulder deposits in NE Aegean Sea: importance of historical sources as tool to support hydrodynamic equations Natural Hazards and Earth System Science, 12, 1109-1118, 2012 Author(s): M. Vacchi, A. Rovere, N. Zouros, and M. Firpo Due to their importance in the assessment of coastal hazards, several studies have focused on geomorphological and sedimentological field evidence of catastrophic wave impacts related to historical tsunami events. Among them, many authors used boulder fields as important indicators of past tsunamis, especially in the Mediterranean Sea. The aim of this study was to understand the mechanism of deposition of clusters of large boulders, consisting of beachrock slabs, which were found on the southern coasts of Lesvos Island (NE Aegean Sea). Methods to infer the origin of boulder deposits (tsunami vs. storm wave) are often based on hydrodynamic models even if different environmental complexities are difficult to be incorporated into numerical models. In this study, hydrodynamic equations did not provide unequivocal indication of the mechanism responsible for boulder deposition in the study area. Further analyses, ranging from geomorphologic to seismotectonic data, indicated a tsunami as the most likely cause of displacement of the boulders but still do not allow to totally exclude the extreme storm origin. Additional historical investigations (based on tsunami catalogues, historical photos and aged inhabitants interviews) indicated that the boulders are likely to have been deposited by the tsunami triggered by the 6.7 M s Chios-Karaburum earthquake of 1949 or, alternatively, by minor effects of the destructive tsunami produced by 1956's Amorgos Island earthquake. Results of this study point out that, at Mediterranean scale, to flank numerical models with the huge amount of the available historical data become a crucial tool in terms of prevention policies related to catastrophic coastal events.

Description: Surveying rip current survivors: preliminary insights into the experiences of being caught in rip currents Natural Hazards and Earth System Science, 12, 1201-1211, 2012 Author(s): D. Drozdzewski, W. Shaw, D. Dominey-Howes, R. Brander, T. Walton, A. Gero, S. Sherker, J. Goff, and B. Edwick This paper begins a process of addressing a significant gap in knowledge about people's responses to being caught in rip currents. While rip currents are the primary hazard facing recreational ocean swimmers in Australia, debate exists about the best advice to give swimmers caught in rip currents. Such surf rescue advice – on what to do and how to respond when caught in a rip – relies on empirical evidence. However, at present, knowledge about swimmers reactions and responses to rip currents is limited. This gap is a considerable barrier to providing effective advice to beach goers and to understanding how this advice is utilised (or not) when actually caught in the rip current. This paper reports the findings of a pilot study that focussed on garnering a better understanding of swimmers' experiences when caught in rip currents. A large scale questionnaire survey instrument generated data about rip current survivors' demographics, knowledge of beach safety and their reactions and responses when caught in a rip current. A mix of online and paper surveys produced a total of 671 completed surveys. Respondents were predominantly an informed group in terms of rip current knowledge, beach experience and had a high self-rated swimming ability. Preliminary insights from the survey show that most respondents recalled a "swim across the rip/parallel to the beach" message when caught in the rip and most escaped unassisted by acting on this message. However, while nearly a quarter of respondents recalled a message of "not to panic", short answer responses revealed that the onset of panic inhibited some respondents from recalling or enacting any other type of beach safety message when caught in the rip current. Results also showed that despite the research sample being younger, competent and frequent ocean swimmers, they were more likely to swim at unpatrolled beaches and outside of the red and yellow safety flags. Moreover, they were still caught in a rip current and they panicked. The findings of this study have significant implications for a range of demographic groups of differing beach safety knowledge and swimming ability who may be caught in rip currents behave, we know very little about how beach goers may respond to being caught in them.

Description: Geological record of tsunami inundations in Pantano Morghella (south-eastern Sicily) both from near and far-field sources Natural Hazards and Earth System Science, 12, 1185-1200, 2012 Author(s): F. Gerardi, A. Smedile, C. Pirrotta, M. S. Barbano, P. M. De Martini, S. Pinzi, A. M. Gueli, G. M. Ristuccia, G. Stella, and S. O. Troja Analysis of tsunami deposits from the Pantano Morghella area provided geological evidence for two inundations occurred along the south-eastern Ionian coast of Sicily. Pantano Morghella is a large pond characterised by a fine-grained sedimentation indicating a low-energy depositional environment. Two anomalous yellow sandy layers found at different depths indicate the occurrence of high-energy marine inundations. We studied sedimentological and paleontological features of the anomalous deposits as well as their spatial distribution observing the following properties: different facies with respect to the local stratigraphic sequence; erosive bases, rip-up clasts and broken elements testifying violent deposition mechanisms; macro and micro fauna of marine environment; relatively constant thickness throughout most of the depositional zone with thinning at the distal end; large sand sheets that extend inland. These observations, jointly with their infrequency in the sedimentary record and the age indicating a fast deposition, provided strong evidence for tsunami inundations. Correlations between anomalous layers and historical tsunamis are supported by radiocarbon and OSL dating results. The younger deposit is likely due to the 1908 near-source tsunami, whereas the flooding of the oldest event is most likely associated with a far and large source, the Crete 365 AD earthquake.

Description: Relation between seismicity and pre-earthquake electromagnetic emissions in terms of energy, information and entropy content Natural Hazards and Earth System Science, 12, 1179-1183, 2012 Author(s): S. M. Potirakis, G. Minadakis, and K. Eftaxias In this paper we show, in terms of Fisher information and approximate entropy, that the two strong impulsive kHz electromagnetic (EM) bursts recorded prior to the Athens earthquake (EQ) (7 September 1999, magnitude 5.9) present compatibility with the radar interferometry data and the seismic data analysis, which indicates that two fault segments were activated during Athens EQ. The calculated Fisher information and approximate entropy content ratios closely follow the radar interferometry result that the main fault segment was responsible for 80 % of the total energy released, while the secondary fault segment for the remaining 20 %. This experimental finding, which appears for the first time in the literature, further enhances the hypothesis for the seismogenic origin of the analyzed kHz EM bursts.

Description: Brief Communication "Rain effect on the load of tephra deposits" Natural Hazards and Earth System Science, 12, 1229-1233, 2012 Author(s): G. Macedonio and A. Costa Accumulation of tephra fallout produced during explosive eruptions can cause roof collapses in areas near the volcano, when the weight of the deposit exceeds some threshold value that depends on the quality of buildings. The additional loading of water that remains trapped in the tephra deposits due to rainfall can contribute to increasing the loading of the deposits on the roofs. Here we propose a simple approach to estimate an upper bound for the contribution of rain to the load of pyroclastic deposits that is useful for hazard assessment purposes. As case study we present an application of the method in the area of Naples, Italy, for a reference eruption from Vesuvius volcano.

Description: The earthquake sedimentary record in the western part of the Sea of Marmara, Turkey Natural Hazards and Earth System Science, 12, 1235-1254, 2012 Author(s): L. Drab, A. Hubert Ferrari, S. Schmidt, and P. Martinez The submarine part of the North Anatolian Fault (NAF) is a very significant hazard for the 12 million people living in Istanbul (Turkey). An accurate seismic risk assessment necessitates paleoseismological data, which can be retrieved in the Marmara Sea by using sedimentary cores. Here, a record of turbidites was obtained in five cores, spanning the Tekirdağ Basin, the Western High and the Central Basin linked by the Tekirdağ fault segment. The turbidites are synchronous at different sites across the two basins and through the structural high pointing to shaking by earthquakes as a triggering mechanism. In particular, the M = 7.4 1912 Mürefte earthquake left a distinctive sedimentary imprint in all the studied cores. Radiocarbon dating implies a turbidite recurrence interval of about 300 yr. The low number of seismo-turbidites documented in the Central Basin compared to the Tekirdağ Basin suggests quasi-synchronous ruptures of the Tekirdağ Segment and the adjacent Central Segment of the NAF or a partial seismic slip on the Central Segment. Both scenarios have implications regarding seismic hazard. Finally, though we obtained a paleoseismological record of the ruptures along the Tekirdağ Segment, further chronological constraints are needed to better date the events and to confirm the completeness of the obtained record.

Description: Deconvolution effect of near-fault earthquake ground motions on stochastic dynamic response of tunnel-soil deposit interaction systems Natural Hazards and Earth System Science, 12, 1151-1157, 2012 Author(s): K. Hacıefendioğlu The deconvolution effect of the near-fault earthquake ground motions on the stochastic dynamic response of tunnel-soil deposit interaction systems are investigated by using the finite element method. Two different earthquake input mechanisms are used to consider the deconvolution effects in the analyses: the standard rigid-base input and the deconvolved-base-rock input model. The Bolu tunnel in Turkey is chosen as a numerical example. As near-fault ground motions, 1999 Kocaeli earthquake ground motion is selected. The interface finite elements are used between tunnel and soil deposit. The mean of maximum values of quasi-static, dynamic and total responses obtained from the two input models are compared with each other.

Description: Assessing precipitation distribution impacts on droughts on the island of Crete Natural Hazards and Earth System Science, 12, 1159-1171, 2012 Author(s): A.-E. K. Vrochidou and I. K. Tsanis Precipitation records from 56 stations on the island of Crete (Greece) revealed that areal mean annual precipitation is of a strong orographic type and its magnitude decreases in west-east direction by as much as 400 mm on average. Amongst many parameters that influence precipitation, the elevation and longitude were the most important and provided the highest spatial correlation. It was found that during the year with minimum precipitation, the precipitation shortage was greater at high elevations while the precipitation excess during the year with maximum precipitation was greater in the western part of the island. The assessment of the spatial and temporal distribution of droughts was carried out with the aid of the Spatially Normalized Standardized Precipitation Index (SN-SPI) for the period 1974–2005 in order to compare drought conditions between neighbouring areas of differing precipitation heights. The analysis showed that severe droughts occurred around the year 1992–1993, with a duration of up to 3 yr. Multiple linear regression (MLR) modeling of precipitation in conjunction with cluster analysis of drought duration exhibits the linkage between precipitation, droughts and geographical factors. This connection between spatial precipitation distribution and geographical parameters provides an important clue for the respective spatial drought pattern. The above findings on the spatio-temporal drought distribution will update the current~drought management plans by developing more precise drought warning systems.

Description: Brief communication "Evaluating European Coastal Evolution using Bayesian Networks" Natural Hazards and Earth System Science, 12, 1173-1177, 2012 Author(s): M. L. Yates and G. Le Cozannet The coastal zone is a complex environment in which a variety of forcing factors interact causing shoreline evolution. Coastal managers seek to predict coastal evolution and to identify regions vulnerable to erosion. Here, a Bayesian network is developed to identify the primary factors influencing decadal-scale shoreline evolution of European coasts and to reproduce the observed evolution trends. Sensitivity tests demonstrate the robustness of the model, showing higher predictive capabilities for stable coasts than for eroding coasts. Finally, the study highlights the need to update and expand large-scale coastal data sets, particularly by including local scale processes and anthropogenic impacts.

Description: Adaptive modelling of long-distance wave propagation and fine-scale flooding during the Tohoku tsunami Natural Hazards and Earth System Science, 12, 1213-1227, 2012 Author(s): S. Popinet The 11 March 2011 Tohoku tsunami is simulated using the quadtree-adaptive Saint-Venant solver implemented within the Gerris Flow Solver. The spatial resolution is adapted dynamically from 250 m in flooded areas up to 250 km for the areas at rest. Wave fronts are tracked at a resolution of 1.8 km in deep water. The simulation domain extends over 73° of both latitude and longitude and covers a significant part of the north-west Pacific. The initial wave elevation is obtained from a source model derived using seismic data only. Accurate long-distance wave prediction is demonstrated through comparison with DART buoys timeseries and GLOSS tide gauges records. The model also accurately predicts fine-scale flooding compared to both satellite and survey data. Adaptive mesh refinement leads to orders-of-magnitude gains in computational efficiency compared to non-adaptive methods. The study confirms that consistent source models for tsunami initiation can be obtained from seismic data only. However, while the observed extreme wave elevations are reproduced by the model, they are located further south than in the surveyed data. Comparisons with inshore wave buoys data indicate that this may be due to an incomplete understanding of the local wave generation mechanisms.

Description: Linking the actors and policies throughout the disaster management cycle by "Agreement on Objectives" – a new output-oriented management approach Natural Hazards and Earth System Science, 12, 1085-1107, 2012 Author(s): S. Greiving, S. Pratzler-Wanczura, K. Sapountzaki, F. Ferri, P. Grifoni, K. Firus, and G. Xanthopoulos Current management of disaster risks is often fragmented due to a lack of coordination between involved actors, i.e. civil protection and spatial planning – a phenomenon which is known as the "problem of interplay". This paper presents an output-oriented risk management approach ("parametric governance"). Here, the modality of the achievement of objectives remains in the hands of the given addressees. This implies a shift from a top-down to a more collaborative, process-oriented form of decision-making. The approach has been successfully applied in two hazard cases and three administrative contexts: (a) the City of Dortmund (Germany) facing flash floods, (b) East Attica region (Greece) facing forest fires, and (c) Lazio Region (Italy) also facing forest fires. As proved by the applications of the concept, a dialogue among experts, stakeholders, and decision-makers is indispensable in order to guarantee inclusion of all diverse and competing values, opinions, and claims. Moreover, a structured communication path is needed to meet the requirements of a risk governance process. Finally, a win-win-situation among the involved actors has to be created to reach an agreement on common goals and actions to achieve them in due time.