ALBERT

Description: Scenario based approach for multiple source Tsunami Hazard assessment for Sines, Portugal Natural Hazards and Earth System Sciences Discussions, 3, 4663-4693, 2015 Author(s): M. Wronna, R. Omira, and M. A. Baptista In this paper, we present a scenario-based approach for tsunami hazard assessment for the city and harbour of Sines – Portugal, one of the test-sites of project ASTARTE. Sines holds one of the most important deep-water ports which contains oil-bearing, petrochemical, liquid bulk, coal and container terminals. The port and its industrial infrastructures are facing the ocean southwest towards the main seismogenic sources. This work considers two different seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, we selected a total of six scenarios to assess the tsunami impact at the test site. The tsunami simulations are computed using NSWING a Non-linear Shallow Water Model With Nested Grids. In this study, the static effect of tides is analysed for three different tidal stages MLLW (mean lower low water), MSL (mean sea level) and MHHW (mean higher high water). For each scenario, inundation is described by maximum values of wave height, flow depth, drawback, runup and inundation distance. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at Sines test site considering the single scenarios at mean sea level, the aggregate scenario and the influence of the tide on the aggregate scenario. The results confirm the composite of Horseshoe and Marques Pombal fault as the worst case scenario. It governs the aggregate scenario with about 60 % and inundates an area of 3.5 km 2 .

Description: A numerical study of the early stages of a tropical cyclogenesis in relation to the MJO Natural Hazards and Earth System Sciences Discussions, 3, 4919-4935, 2015 Author(s): J. Guerbette, M. Plu, C. Barthe, and J.-F. Mahfouf The role of an active phase of the Madden–Julian Oscillation (MJO) on the evolution of a mesoscale convective systems (MCS) leading to a tropical depression is investigated in the South-West Indian Ocean during the Dynamics of the Madden–Julian Oscillation (DYNAMO) field experiment, with a numerical limited-area atmospheric model. A mesoscale vortex is followed in the low-troposphere from the initiation of the active MJO phase. It is shown that the interaction of the vortex with the Equatorial jet associated with the MJO plays an important role on the vortex development. As the vortex encounters the southern part of the low-level jet, it undergoes intensification that is explained by the barotropic conversion of kinetic energy from the low-level jet to the vortex.

Description: The 9 September 2010 torrential rain and flash flood in the Dragone catchment, Atrani, Amalfi Coast (Southern Italy) Natural Hazards and Earth System Sciences Discussions, 3, 4715-4751, 2015 Author(s): C. Violante, G. Braca, E. Esposito, and G. Tranfaglia In this paper we use a multi-hazard approach to analyse the 9 September 2010 flash-flood occurred in the Dragone basin, a 9 km 2 catchment located along the Amalfi rocky coastal range, Southern Italy. In this area, alluvial-fan-flooding is the most frequent and destructive geologic hazards since Roman time. Sudden torrent of waters (flash flood) are caused by high-intensity and very localized cloudbursts of short duration inducing slope erosion and sediment delivery from slope-to-stream. The elevated bed load transport produces fast-moving hyperconcentrated flows with significant catastrophic implications for communities living at stream mouth. The 9 September 2010 rainstorm event lasted 1 h with an intensity rainfall peak nearly to 120 mm h −1 . High topographic relief of the Amalfi coastal range and positive anomalies of the coastal waters conditioned the character of the convective system. Based on geological data and post-event field evidence and surveys, as well as homemade-videos, and eyewitness accounts the consequent flash-flood mobilized some 25 000 m 3 of materials with a total (water and sediment) peak flow of 80 m 3 s −1 . The estimated peak discharge of only clear water was about 65 m 3 s −1 . This leads to a sediment bulking factor of 1.2 that corresponds to a flow with velocities similar to those of water during a flood.

Description: Teaching disaster preparedness via a mobile device: a study of Auckland Civil Defence's Smartphone Application Natural Hazards and Earth System Sciences Discussions, 3, 4555-4583, 2015 Author(s): O. Kulemeka This content analysis study examined whether a disaster preparedness education smartphone application created by a New Zealand city matches what experts say are effective ways of teaching disaster preparedness and teaching via an app. The app was assessed to ascertain if it excelled as a platform for learning, communicated effectively, addressed factors that can hinder people from preparing, and provided information for special needs populations. Results show that the app addressed most factors that hinder preparedness, provided information for some special needs populations, excelled as a platform for learning, and communicated effectively. The app's weaknesses include the fact that it lacked targeted information for low-income residents. The findings provide insight on how organizations can effectively use apps to teach disaster preparedness. The author passed away before the publication of this discussion paper. Therefore, a final revised paper is not foreseen.

Description: Inversion kinematics at deep-seated gravity slope deformations: a paleoseismological perspective Natural Hazards and Earth System Sciences Discussions, 3, 4585-4617, 2015 Author(s): F. Pasquarè Mariotto and A. Tibaldi We compare data from three deep-seated gravity slope deformations (DSGSDs) where paleoseismological techniques were applied in artificial trenches. At all trenches, located in metamorphic rocks of the Italian Alps, there is evidence of extensional deformation given by normal movements along slip planes dipping downhill or uphill, and/or fissures, as expected in gravitational failure. However, we document and illustrate – with the aid of trenching – the evidence of reverse movements. The reverse slips occurred mostly along the same planes along which normal slip occurred, and produced drag folds in unconsolidated Holocene sediments as well as the superimposition of substrate rocks on Holocene sediments. Since trenches are located in different positions with respect to the slope affected by the DSGSD, it is possible to suggest that reverse slip might occur both at the toe portions of DSGSDs and in their central-upper portions. When the age relationships between the two deformation kinematics can be sorted out, they clearly indicate that reverse slips postdate normal ones. Our data suggest that during the development of long-lived DSGSDs, inversion kinematics may occur in different sectors of the unstable rock mass. The inversion is interpreted as either due to locking of the frontal blocks of a DSGSD, or the relative decrease in the rate of downward movement in the frontal blocks with respect to the rear blocks.

Description: Factors of subjective heat stress of urban citizens in contexts of everyday life Natural Hazards and Earth System Sciences Discussions, 3, 4619-4661, 2015 Author(s): T. Kunz-Plapp, J. Hackenbruch, and J. W. Schipper Heat waves and the consequent heat stress of urban populations have a growing relevance in urban risk management and strategies of urban adaptation to climate change. In this context, social science studies on subjective heat stress of urban citizens are a new emerging field. To contribute to the understanding of subjective heat stress and its major determinants in a daily life perspective, we conducted a questionnaire survey with 323 respondents in Karlsruhe, Germany, after a heat wave in July and August 2013. Statistical data analysis showed that heat stress is an issue permeating everyday activities. It was found that the subjective heat stress at home is lower than at work and in general. Subjective heat stress in general, at home, and at work was determined by the health impairments experienced during the heat and the feeling of being helplessly exposed to the heat. For heat stress at home, additionally characteristics of the residential building and the built environment played a role. Although the rate of implemented coping measures was rather high, coping measures showed no uniform effect for the subjective heat stress. The results furthermore show that coping with heat is performed within the scopes of action in daily life. We conclude that in terms of urban adaptation strategies, further research is needed to understand how various processes of daily social (work) life enable or limit individual coping and adaptation capacities and that communication strategies are important for building capacities to better cope with future heat waves.

Description: InSAR observations of the 2009 Racha earthquake, the Republic Georgia Natural Hazards and Earth System Sciences Discussions, 3, 4695-4714, 2015 Author(s): E. Nikolaeva and T. R. Walter Central Georgia is an area strongly affected by earthquake and landslide hazards. On 29 April 1991 a major earthquake ( M w = 7.0) struck the Racha region in the republic Georgia, followed by aftershocks and significant afterslip. The same region was hit by another major event ( M w = 6.0) on 7 September 2009. The aim of the study reported here was to utilize geodetic data as synthetic aperture radar interferometry (InSAR) to improve a knowledge about the spatial pattern of deformation due to the earthquakes in the seismic active central Georgia. There were no actual earthquake observations by InSAR in Georgia. We used the multi-temporal ALOS L-band InSAR data to produce interferograms spanning times before and after the 2009 earthquake. We detected a local uplift around 10 cm in the interferogram near the earthquake's epicenter whereas evidence of surface ruptures could not be found in the field along the active thrust fault. We simulated a deformation signal which could be created by the 2009 Racha earthquake on the basis of local seismic records and by using an elastic dislocation model. The observed InSAR deformation is in good agreement with our model. We compared our modeled fault surface of the September 2009 with the April 1991 Racha earthquake fault surfaces, and identify the same fault or a sub-parallel fault of the same system as the origin. The patch that was active in 2009 is just adjacent to the 1991 patch, indicating a possible mainly westward propagation direction, with important implications for future earthquake hazards.

Description: Risk for large-scale fires in boreal forests of Finland under changing climate Natural Hazards and Earth System Sciences Discussions, 3, 4753-4795, 2015 Author(s): I. Lehtonen, A. Venäläinen, M. Kämäräinen, H. Peltola, and H. Gregow The target of this work was to assess the impact of projected climate change on the number of large forest fires (over 10 ha fires) and burned area in Finland. For this purpose, we utilized a strong relationship between fire occurrence and the Canadian fire weather index (FWI) during 1996–2014. We used daily data from five global climate models under representative concentration pathway RCP4.5 and RCP8.5 scenarios. The model data were statistically downscaled onto a high-resolution grid using the quantile-mapping method before performing the analysis. Our results suggest that the number of large forest fires may double or even triple during the present century. This would increase the risk that some of the fires could develop into real conflagrations which have become almost extinct in Finland due to active and efficient fire suppression. Our results also reveal substantial inter-model variability in the rate of the projected increase in forest-fire danger. We moreover showed that the majority of large fires occur within a relatively short period in May and June due to human activities and that FWI correlates poorer with the fire activity during this time of year than later in summer when lightning is more important cause of fires.

Description: Snow instability evaluation: calculating the skier-induced stress in a multi-layered snowpack Natural Hazards and Earth System Sciences Discussions, 3, 4833-4869, 2015 Author(s): F. Monti, J. Gaume, A. van Herwijnen, and J. Schweizer The process of dry-snow slab avalanche formation can be divided into two phases: failure initiation and crack propagation. Several approaches tried to quantify slab avalanche release probability in terms of failure initiation based on shear stress and strength. Though it is known that both the properties of the weak layer and the slab play a major role in avalanche release, most previous approaches only considered slab properties in terms of slab depth, average density and skier penetration. For example, for the skier stability index, the additional stress (e.g. due to a skier) at the depth of the weak layer is calculated by assuming that the snow cover can be considered a semi-infinite, elastic half-space. We suggest a new approach based on a simplification of the multi-layered elasticity theory in order to easily compute the additional stress due to a skier at the depth of the weak layer taking into account the layering of the snow slab and the substratum. We first tested the proposed approach on simplified snow profiles, then on manually observed snow profiles including a stability test and, finally, on simulated snow profiles. Our simple approach well reproduced the additional stress obtained by finite element simulations for the simplified profiles – except that the sequence of layering in the slab cannot be replicated. Once implemented into the classical skier stability index and applied to manually observed snow profiles classified into different stability classes, the classification accuracy improved with the new approach. Finally, we implemented the refined skier stability index into the 1-D snow cover model SNOWPACK. For the two study cases presented in this paper, this approach showed promising results even though further verification is still needed. In the future, we intend to implement the proposed approach for describing skier-induced stress within a multi-layered snowpack into more complex models which take into account not only failure initiation but also crack propagation.

Description: Partnerships for affordable and equitable disaster insurance Natural Hazards and Earth System Sciences Discussions, 3, 4797-4832, 2015 Author(s): J. Mysiak and C. D. Pérez-Blanco Extreme events are becoming more frequent and intense, inflating the economic damages and social hardship set-off by natural catastrophes. Amidst budgetary cuts, there is a growing concern on societies' ability to design solvent disaster recovery strategies, while addressing equity and affordability concerns. The participation of private sector along with public one through Public-Private Partnerships (PPPs) has gained on importance as a means to address these seemingly conflicting objectives through the provision of (catastrophic) natural hazard insurance. This is the case of many OECD countries, notably some EU Member States such as the United Kingdom and Spain. The EU legislator has adapted to this new scenario and recently produced major reforms in the legislation and regulation that govern the framework in which PPPs for (catastrophic) natural hazard insurance develop. This paper has a dual objective: (1) review the complex legal background that rules the provision of insurance against natural catastrophes in the EU after these major reforms, (2) assess the implications of the reforms and offer concise Policy Guiding Principles.