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Probst et al., 2012. Tropical Cyclone Giovanna - Madagascar February 2012. JRC Technical Report.
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Tags: Cyclones

Pamela Probst, Giovanni Franchello, Alessandro Annunziato, Tom De Groeve, Luca Vernaccini, Andreas Hirner, Ioannis Andredakis, 2012. Tropical Cyclone Giovanna - Madagascar February 2012. JRC Technical Report.

JRC has developed GDACS, an early warning system created to alert the humanitarian community about potential disasters which are under development. Tropical cyclones are some of the most damaging events, affecting the coastal population with three dangerous effects: strong wind, heavy rain and storm surge. GDACS includes the analysis of the first and the second effects, and recently also the third effect (storm surge) has been implemented.
An impact assessment for all the three alerts are presented in the r eport.
Wind alert level estimated by GDACS was Red, due to the high wind and the high vulnerability of the affected country. The wind impact assessment by BNGRC has confirmed that most of the damage due to Giovanna was caused by strong winds. The region most affected has been Antisanana. The rain impact alert level in GDACS is based on the estimation of the total accumulation of rainfall on land using NOAA eTRaP data. The applicability of the data was considered fine for alert levels at regional level, but not at local level due to spatial uncertainty.
The storm surge GDACS alert level is based on the calculations of the JRC code HyFlux2. The accuracy of the estimated storm surge height could not be established because the available tide gauge was malfunctioning. We compared our results with two UNOSAT/UNITAR impact assessment maps of two damaged cities (Brickaville and Vatomadry). These maps gave a clear indication of building damages, as a result of strong winds and storm surge while the JRC calculations showed a storm surge in the order of 1 m.
Overall, the GDACS models performed well. Alert levels for all hazard components were consistent with the observed impact. The location and timing of the information could accurately identify the affected provinces. GDACS information is appropriate for near real-time strategic decision making, but not – without additional field validation – for field operations.

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Probst et al., 2012. Tropical Cyclone Isaac - August 2012. JRC Technical Report.
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Tags: Cyclones
Pamela Probst, Giovanni Franchello, Alessandro Annunziato, Tom De Groeve, Ioannis Andredakis, 2012. Tropical Cyclone ISAAC. USA, August 2012.
Tropical Cyclone ISAAC, after causing damage and deaths in Haiti, moved towards the coast of SE Louisiana (USA), where it made two landfalls. After the second landfall, it started moving inland in SE Louisiana, passing W of New Orleans on Aug 29 afternoon/evening (UTC), weakening into a tropical storm, then late on Aug 30 became a tropical depression. Tropical Cyclone ISAAC affected the southern parts of Louisiana, Mississippi and Alabama with heavy rainfall, strong winds and storm surge, causing flooding, power outages, damage to property and, according to media report, killing at least 7 people. Most of this damage has been caused by heavy rains and storm surge. The Joint Research Centre (JRC) followed the event through the information automatically collected and analysed in the Global Disasters Alerts and Coordination System (GDACS). GDACS classification, for TC ISAAC in the USA, was: Green for the wind impact, Orange for rain impact and Red for storm surge impact.
On 27 August 2012, 2 days before the landfall, the JRC HyFlux2 storm surge model indicated a possible storm
surge in the order of 2.5-3.5m for Aug 29 morning (UTC) in the coastal area E-SE of New Orleans, Louisiana Online observations and NOAA reports confirmed the forecasts. This report analyses and discusses the GDACS automatic impact assessments and compares the JRC HyFlux2 deterministic storm surge forecasts with the probabilistic forecasts provided by NOAA.
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Simulation of storm surge for a fictive cyclone Trina in Samoa.
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Tags: Cyclones

 For a simulation exercise of the Samoan authorities, the Joint Research Centre modelled the storm surge associated to a fictive typhoon. "Typhoon Trina is forecast to hist the Samoa Islands on 30 November 2011, causing storm surge up to 1.8m."

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Franchello, G. and A. Annunziato, 2012. The Samoa Tsunami of 29 September 2009 - Early Warning System and Inundation Assessment.
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Tags: Tsunami

On 29 September 2009 at 17:48:11 UTC, a large earthquake of magnitude 8 struck off-shore of the Samoa Islands and generated a large tsunami that destroyed several villages and caused more than 160 fatalities. This report first presents the characteristics of the earthquake and discusses the best estimations for the fault parameters, which are the necessary input data for the hydrodynamic tsunami calculations. Then, the assessment of the near-real time systems invoked by the Global Disasters Alert and Coordination System (GDACS, http://www.gdacs.org/) and the post-event calculations are performed, making comparisons with the observed tidal measurements and post-event survey. It was found that the most severely damaged locations are the Southern section of the Western Samoa Islands, Tutuila Isl in American Samoa and Niuatoputapu Isl in Tonga. This is in agreement with the locations indicated by the Red Cross as the most affected and with the results of the post-tsunami surveys.Furthermore, an attempt was made to map the inundation events using more detailed digital elevation models (DEM) and hydrodynamic modelling with good results. The flooded areas for which we had satellite images and post-tsunami surveys confirm the inundated areas identified correctly by the hydrodynamic model. Indications are given on the DEM grid size needed for the different simulations.

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Probst, P. and G. Franchello. Global storm surge forecast and inundation modeling.
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Tags: Cyclones

 Tropical cyclones (TCs) are some of the most damaging events. They occur in yearly cycles and affect the coastal population with three dangerous effects: heavy rain, strong wind and storm surge. In order to estimate the area and the population affected by a cyclone, all the three types of physical impacts must be taken into account. Storm surge is an abnormal rise of water above the astronomical tides, generated by strong winds and drop in the atmospheric pressure. The report describes the implementation of such phenomena in the JRC HyFlux2 code, which is routinely used in GDACS (www.gdacs.org) to model inundations due to tsunami run-ups.

The first aim of this work is to identify which source of information (provided by the different weather forecast centers) allows the specification of the pressure and wind fields of the TCs at global level. The lack of a global and free downloadable TC wind and pressure datasets has led the JRC to develop a Monte Carlo method to determine the Holland’s parameters using the world available wind radii data (advisory and forecast). The obtained Holland’s parameters are therefore used to obtain pressure and wind fields which are the forcing of the HyFlux2 storm surge modeling.
The developed methodology has been validated for four TCs: Earl, Nargis, Katrina and Yasi. The preliminary results show that it is possible to forecast the effects of storm surges by several days in advance.
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Zamora, N., Franchello, G., Annunziato, A., 2011. 1 April 2007 Solomon Island Tsunami: Case Study to Validate JRC Tsunami Codes
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Tags: Tsunami

The calculations in the propagation assessment subsection were performed using: SWAN-JRC, HYFLUX2, TUNAMI-N2 and NOAA-MOST code. In the inundation assessment the HYFLUX2 numerical code, initialized with the Tanioka fault model was used.

The deformation comparison with field measured data shows that none of the “quick” fault mechanism was able to estimate correctly the measured value. The best model is the empirical model by Tanioka which was obtained by trying to reproduce the measured value.

From the published fault mechanism the one that shows a better correlation with measurements is the simple cosinuosoidal model. Results of simulations done with 300 m grid, show a maximum wave height of 7.5 m. Though the maximum run up reported was 10 m in Tapurai site, Simbi Island, the simulation results are encouraging.

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Franchello, G., 2009. Shoreline tracking and implicit source terms for a well balanced inundation model.
Downloaded 1803 time(s)
Tags: Cyclones, Floods, Tsunami

The HyFlux2 model has been developed to simulate severe inundation scenario due to dam break, flash flood and tsunami-wave run-up. The model solves the conservative form of the two-dimensional shallow water equations using the finite volume method. The interface flux is computed by a Flux Vector Splitting method for shallow water equations based on a Godunov-type approach. A second-order scheme is applied to the water surface level and velocity, providing results with high accuracy and assuring the balance between fluxes and sources also for complex bathymetry and topography. Physical models are included to deal with bottom steps and shorelines. The second-order scheme together with the shoreline-tracking method and the implicit source term treatment makes the model well balanced in respect to mass and momentum conservation laws, providing reliable and robust results.

The developed model is validated in this paper with a 2D numerical test case and with the Okushiri tsunami run up problem. It is shown that the HyFlux2 model is able to model inundation problems, with a satisfactory prediction of the major flow characteristics such as water depth, water velocity, flood extent, and flood-wave arrival time. The results provided by the model are of great importance for the risk assessment and management.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
Int. J. Numer. Meth. Fluids 2010; 63:1123–1146
Published online 31 July 2009 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/fld.2121
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Cruz, A. M., Franchello, G., Krausmann, E., 2009. Assessment of Tsunami Risk to an Oil Refinery in Southern Italy.
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Industrial facilities located in coastal areas subject to tsunami hazards may be at risk of tsunami impact and damage. Furthermore, if hazardous materials are present these can be accidentally released impacting nearby residents and dispersing into the environment. In this report we present the results of a study which analyzed the potential impact of two tsunamis originating in the Tyrrhenian Sea and their consequences at an industrial facility located on the coast in northeastern Sicily.

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Franchello, G., and E. Krausmann, 2008. HyFlux2: a numerical model for the impact assessment of severe inundation scenarios.
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Tags: Floods

HyFlux2: a numerical model for the impact assessment of severe inundation scenario to chemical facilities and downstream environment. The HyFlux2 model has been developed to simulate flood inundation due to dam break. However, it is able to simulate other severe inundation scenarios such as tsunami-wave run-up and flash flood. The model solves the conservative form of the two-dimensional shallow water equations using the finite volume method. The interface flux is computed by a Flux Vector Splitting method based on a Godunov-type approach. A second-order scheme is applied to the water surface level and velocity, assuring the balance between fluxes and sources also for complex bathymetry and topography, i.e. also in presence of bottom steps and shorelines. The second-order scheme provides results with high accuracy, also in the presence of dry/wet fronts.

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Franchello, G., 2008. Modelling Shallow Water Flows by a High Resolution Riemann Solver
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Tags: Cyclones, Floods, Tsunami

Shock-capturing methods originally developed for compressible gas dynamics have been applied to shallow water flows. The proposed model is a finite volume Flux Vector Splitting Riemann Solver with a second order resolution scheme andimplicit treatment of the source terms.

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E. Gutiérrez, F. Taucer, T. De Groeve, D. H. A. Al-Khudhairy, and J. M. Zaldivar, Analysis of Worldwide Earthquake Mortality using Multivariate Demogr
Tags: Earthquakes

In this paper, mortality in the immediate aftermath of an earthquake is studied on a worldwide scale using multivariate analysis. A statistical method is presented that analyzes reported earthquake fatalities as a function of a heterogeneous set of parameters selected on the basis of their presumed influence on earthquake mortality. The ensemble was compiled from demographic, seismic, and reported fatality data culled from available records of past earthquakes organized in a geographic information system. The authors consider the statistical relation between earthquake mortality and the available data ensemble, analyze the validity of the results in view of the parametric uncertainties, and propose a multivariate mortality analysis prediction method. The analysis reveals that, although the highest mortality rates are expected in poorly developed rural areas, high fatality counts can result from a wide range of mortality ratios that depend on the effective population size.

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De Groeve T. Global Disaster Alert and Coordination System: More Effective and Efficient Humanitarian Response . In Conference Proceedings: A. Jones,
The Global Disaster Alert and Coordination System, jointly developed in 2005 by the European Commission and the United Nations, combines existing web-based disaster information management systems with the aim to alert the international community in case of major sudden-onset disasters and to facilitate the coordination of international response during the relief phase of the disaster. The disaster alerts are based on automatic hazard information retrieval and real-time GIS-based consequence analysis. This paper shows how information systems in general and GDACS in particular can improve efficiency and effectiveness of humanitarian response.
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De Groeve T, Katjizie M. Validation of Global Flood Detection System for Namibian rivers (Part 1). Ispra (Italy): Joint Research Centre of the Europea
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Tags: Floods

During the 2009-2010 flood season, the Namibian Hydrological Service used the Global Flood Detection System (GFDS) on an experimental basis to obtain information on the flood status of the rivers crossing Namibia. GFDS automatically produces daily satellite observations into regional flood maps and virtual hydrographs for any location in the world. The tests in Namibia were the first large scale validation study of the system including local hydrological services since the system was first developed in 2007. As part of the collaboration between JRC and the Namibian Government, JRC hosted a staff member of the Namibian Hydrological Service during a three month period to jointly review the performance and accuracy of GFDS data and specify additional improvements and requirements for the next flood season.

 
 Documents
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 TitleOwnerCategoryModified DateSize DescriptionClicks
Tsunami Solomon Islands 6 Feb 2013 (Map)SuperUser Account 11/26/201311.85 KBDownloadMap showing the results of the tsunami calculations performed by GDACS, including identification of the wave heights in populated places.3011