scholarly journals Tsunami hazard assessment in El Salvador, Central America, from seismic sources through flooding numerical models

2013 ◽  
Vol 1 (3) ◽  
pp. 2127-2161 ◽  
Author(s):  
J. A. Álvarez-Gómez ◽  
Í. Aniel-Quiroga ◽  
O. Q. Gutiérrez-Gutiérrez ◽  
J. Larreynaga ◽  
M. González ◽  
...  
Keyword(s):  
High Resolution ◽  
El Salvador ◽  
Central America ◽  
Hazard Assessment ◽  
Numerical Models ◽  
Tsunami Hazard ◽  
Essential Information ◽  
Eastern Area ◽  
Run Up ◽  
The Impact

Abstract. El Salvador is the smallest and most densely populated country in Central America; its coast has approximately a length of 320 km, 29 municipalities and more than 700 000 inhabitants. In El Salvador there have been 15 recorded tsunamis between 1859 and 2012, 3 of them causing damages and hundreds of victims. The hazard assessment is commonly based on propagation numerical models for earthquake-generated tsunamis and can be approached from both Probabilistic and Deterministic Methods. A deterministic approximation has been applied in this study as it provides essential information for coastal planning and management. The objective of the research was twofold, on the one hand the characterization of the threat over the entire coast of El Salvador, and on the other the computation of flooding maps for the three main localities of the Salvadorian coast. For the latter we developed high resolution flooding models. For the former, due to the extension of the coastal area, we computed maximum elevation maps and from the elevation in the near-shore we computed an estimation of the run-up and the flooded area using empirical relations. We have considered local sources located in the Middle America Trench, characterized seismotectonically, and distant sources in the rest of Pacific basin, using historical and recent earthquakes and tsunamis. We used a hybrid finite differences – finite volumes numerical model in this work, based on the Linear and Non-linear Shallow Water Equations, to simulate a total of 24 earthquake generated tsunami scenarios. In the western Salvadorian coast, run-up values higher than 5 m are common, while in the eastern area, approximately from La Libertad to the Gulf of Fonseca, the run-up values are lower. The more exposed areas to flooding are the lowlands in the Lempa River delta and the Barra de Santiago Western Plains. The results of the empirical approximation used for the whole country are similar to the results obtained with the high resolution numerical modelling, being a good and fast approximation to obtain preliminary tsunami hazard estimations. In Acajutla and La Libertad, both important tourism centres being actively developed, flooding depths between 2 and 4 m are frequent, accompanied with high and very high person instability hazard. Inside the Gulf of Fonseca the impact of the waves is almost negligible.

scholarly journals Tsunami hazard assessment in El Salvador, Central America, from seismic sources through flooding numerical models.

2013 ◽  
Vol 13 (11) ◽  
pp. 2927-2939 ◽  
Author(s):  
J. A. Álvarez-Gómez ◽  
Í. Aniel-Quiroga ◽  
O. Q. Gutiérrez-Gutiérrez ◽  
J. Larreynaga ◽  
M. González ◽  
...  
Keyword(s):  
High Resolution ◽  
El Salvador ◽  
Central America ◽  
Hazard Assessment ◽  
Numerical Models ◽  
Tsunami Hazard ◽  
Essential Information ◽  
Eastern Area ◽  
Run Up ◽  
The Impact

Abstract. El Salvador is the smallest and most densely populated country in Central America; its coast has an approximate length of 320 km, 29 municipalities and more than 700 000 inhabitants. In El Salvador there were 15 recorded tsunamis between 1859 and 2012, 3 of them causing damages and resulting in hundreds of victims. Hazard assessment is commonly based on propagation numerical models for earthquake-generated tsunamis and can be approached through both probabilistic and deterministic methods. A deterministic approximation has been applied in this study as it provides essential information for coastal planning and management. The objective of the research was twofold: on the one hand the characterization of the threat over the entire coast of El Salvador, and on the other the computation of flooding maps for the three main localities of the Salvadorian coast. For the latter we developed high-resolution flooding models. For the former, due to the extension of the coastal area, we computed maximum elevation maps, and from the elevation in the near shore we computed an estimation of the run-up and the flooded area using empirical relations. We have considered local sources located in the Middle America Trench, characterized seismotectonically, and distant sources in the rest of Pacific Basin, using historical and recent earthquakes and tsunamis. We used a hybrid finite differences–finite volumes numerical model in this work, based on the linear and non-linear shallow water equations, to simulate a total of 24 earthquake-generated tsunami scenarios. Our results show that at the western Salvadorian coast, run-up values higher than 5 m are common, while in the eastern area, approximately from La Libertad to the Gulf of Fonseca, the run-up values are lower. The more exposed areas to flooding are the lowlands in the Lempa River delta and the Barra de Santiago Western Plains. The results of the empirical approximation used for the whole country are similar to the results obtained with the high-resolution numerical modelling, being a good and fast approximation to obtain preliminary tsunami hazard estimations. In Acajutla and La Libertad, both important tourism centres being actively developed, flooding depths between 2 and 4 m are frequent, accompanied with high and very high person instability hazard. Inside the Gulf of Fonseca the impact of the waves is almost negligible.

scholarly journals Deterministic approach for multiple-source tsunami hazard assessment for Sines, Portugal

2015 ◽  
Vol 15 (11) ◽  
pp. 2557-2568 ◽  
Author(s):  
M. Wronna ◽  
R. Omira ◽  
M. A. Baptista
Keyword(s):  
Sea Level ◽  
Wave Height ◽  
Hazard Assessment ◽  
Test Site ◽  
Tsunami Hazard ◽  
Deterministic Approach ◽  
Flow Depth ◽  
Mean Sea Level ◽  
Tsunami Hazard Assessment ◽  
The Impact

Abstract. In this paper, we present a deterministic approach to tsunami hazard assessment for the city and harbour of Sines, Portugal, one of the test sites of project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). Sines has one of the most important deep-water ports, which has oil-bearing, petrochemical, liquid-bulk, coal, and container terminals. The port and its industrial infrastructures face 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, the tsunami hazard is described by maximum values of wave height, flow depth, drawback, maximum inundation area and run-up. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at the 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 source of Horseshoe and Marques de Pombal faults as the worst-case scenario, with wave heights of over 10 m, which reach the coast approximately 22 min after the rupture. It dominates the aggregate scenario by about 60 % of the impact area at the test site, considering maximum wave height and maximum flow depth. The HSMPF scenario inundates a total area of 3.5 km2.

New View of the Solar Chromosphere

2019 ◽  
Vol 57 (1) ◽  
pp. 189-226 ◽  
Author(s):  
Mats Carlsson ◽  
Bart De Pontieu ◽  
Viggo H. Hansteen
Keyword(s):  
High Resolution ◽  
Adaptive Optics ◽  
Numerical Models ◽  
Transverse Magnetic ◽  
Solar Photosphere ◽  
Solar Chromosphere ◽  
Image Reconstruction Techniques ◽  
New Instrumentation ◽  
Field Unit ◽  
The Impact

The solar chromosphere forms a crucial, yet complex and until recently poorly understood, interface between the solar photosphere and the heliosphere. ▪ Advances in high-resolution instrumentation, adaptive optics, image reconstruction techniques, and space-based observatories allow unprecedented high-resolution views of the finely structured and highly dynamic chromosphere. ▪ Dramatic progress in numerical computations allows 3D radiative magnetohydrodynamic forward models to take the place of the previous generation of 1D semiempirical atmosphere models. These new models provide deep insight into complex nonlocal thermodynamic equilibrium chromospheric diagnostics and enable physics-based interpretations of observations. ▪ This combination of modeling and observations has led to new insights into the role of shock waves, transverse magnetic waves, magnetic reconnection and flux emergence in the chromospheric energy balance, the formation of spicules, the impact of ion-neutral interactions, and the connectivity between chromosphere and transition region. ▪ During the next few years, the advent of new instrumentation (integral-field-unit spectropolarimetry) and observatories (ALMA, DKIST), coupled with novel inversion codes and expansion of existing numerical models to deal with ever more complex physical processes (including multifluid approaches), is expected to lead to major new insights into the dominant heating processes in the chromosphere and beyond.

scholarly journals The magnitude and impact of the 431 CE Tierra Blanca Joven eruption of Ilopango, El Salvador

2020 ◽  
Vol 117 (42) ◽  
pp. 26061-26068 ◽  
Author(s):  
Victoria C. Smith ◽  
Antonio Costa ◽  
Gerardo Aguirre-Díaz ◽  
Dario Pedrazzi ◽  
Andrea Scifo ◽  
...  
Keyword(s):  
High Resolution ◽  
El Salvador ◽  
Central America ◽  
State Of The Art ◽  
Ice Core ◽  
Ice Cores ◽  
Ash Layer ◽  
Ice Core Record ◽  
Climatic Impacts ◽  
Eruption Magnitude

The Tierra Blanca Joven (TBJ) eruption from Ilopango volcano deposited thick ash over much of El Salvador when it was inhabited by the Maya, and rendered all areas within at least 80 km of the volcano uninhabitable for years to decades after the eruption. Nonetheless, the more widespread environmental and climatic impacts of this large eruption are not well known because the eruption magnitude and date are not well constrained. In this multifaceted study we have resolved the date of the eruption to 431 ± 2 CE by identifying the ash layer in a well-dated, high-resolution Greenland ice-core record that is >7,000 km from Ilopango; and calculated that between 37 and 82 km3of magma was dispersed from an eruption coignimbrite column that rose to ∼45 km by modeling the deposit thickness using state-of-the-art tephra dispersal methods. Sulfate records from an array of ice cores suggest stratospheric injection of 14 ± 2 Tg S associated with the TBJ eruption, exceeding those of the historic eruption of Pinatubo in 1991. Based on these estimates it is likely that the TBJ eruption produced a cooling of around 0.5 °C for a few years after the eruption. The modeled dispersal and higher sulfate concentrations recorded in Antarctic ice cores imply that the cooling would have been more pronounced in the Southern Hemisphere. The new date confirms the eruption occurred within the Early Classic phase when Maya expanded across Central America.

Evaluation of the sensitivity of open source DEM vs. local high resolution DEM data in tsunami hazard assessment

2020 ◽  
Author(s):  
Duygu Tufekci-Enginar ◽  
M. Lutfi Suzen ◽  
G. Guney Dogan ◽  
Ahmet Cevdet Yalciner
Keyword(s):  
High Resolution ◽  
Open Source ◽  
Spatial Resolution ◽  
Hazard Assessment ◽  
Tsunami Hazard ◽  
Quality Data ◽  
Topographic Data ◽  
Aster Gdem ◽  
Tsunami Hazard Assessment ◽  
Topography Data

<p>Tsunami simulations using high resolution datasets would always resemble the results that are closer to the reality. However, high resolution airborne or spaceborne local datasets have not yet been available for many regions and acquisition of this data is costly or might not even be possible for some locations. This hard-to-reach situation of high resolution datasets obliged researchers to work with open source datasets in their studies, which forces them to cope with the uncertainties of low spatial resolution.</p><p>Tsunami numerical models require both bathymetric and topographic data in order to calculate wave propagation in the water and inundation on the land. Leaving aside the availability of reliable bathymetric data, there are different open source global Digital Elevation Model (DEM) datasets, which are freely available. ASTER GDEM, SRTM and ALOS World 3D are present global open source DEMs that have highest spatial resolution of 30 meters. These three different sources of DEMs are generated using different technologies during data acquisition and different methodologies while processing. Even if they are the best available open source datasets, they all include variable sources of differences and errors.</p><p>This study aims evaluation of the sensitivity of open source DEM datasets against high resolution DEM datasets for tsunami hazard assessment and examination of accuracy of the simulations’ results. A small area in Silivri district of Istanbul is selected as study area, where 1m resolution of topographic data is available. Tsunami simulations are performed using NAMI DANCE GPU with topography data of 1m resolution based on LiDAR measurements and topography data of 30m resolution based on ASTER GDEM, SRTM and ALOS World 3D datasets. The resulted inundation on land and flow depth distributions are plotted and discussed with comparisons.</p><p> </p><p>Acknowledgement: MSc. Bora Yalciner and Assoc. Prof. Dr. Andrey Zaytsev are acknowledged for their contributions in developing tsunami numerical model NAMI DANCE GPU used in this study. The authors also thank Istanbul Metropolitan Municipality, Directorate of Earthquake and Ground Investigation for providing high quality data and close cooperation.</p><p>Keywords: tsunami, hazard assessment, numerical modeling, open source DEM, high-resolution DEM</p>

Reactionary Despotism in Central America

1983 ◽  
Vol 15 (2) ◽  
pp. 295-319 ◽  
Author(s):  
Enrique A. Baloyra-Herp
Keyword(s):  
El Salvador ◽  
Central America ◽  
State Of Exception ◽  
Distinct Form ◽  
Social Actors ◽  
Export Agriculture ◽  
Capitalist State ◽  
The Impact ◽  
Distinct Variety ◽  
National Control

This essay seeks to clarify the particular blend of sociohistorical elements that created a distinct form of authoritarian domination in El Salvador, Guatemala and, to a lesser extent, Nicaragua. Situations of ‘enclave’ versus ‘national control’, the consequences of export agriculture, the impact of the commodity cycle, and relations between the oligarchy and other social actors are examined in a comparative perspective to distil commonalities and differences. The emergence of a distinct variety of the capitalist state of exception followed the crisis of oligarchy brought about by the Depression of the late 1920s and early 1930s. State power became public at the time and the traditional oligarchies no longer ruled directly, although they were able to weave a relatively complex alliance. This is identified as a ‘reactionary coalition’ capable of resisting any change in the model of export agriculture, ‘unreformed’ capitalism, and political authoritarianism. This model is identified as ‘reactionary despotism’, and the contemporary crises of El Salvador, and Nicaragua are related to the deterioration of this form of political domination

scholarly journals Scenario-based numerical modelling and the palaeo-historic record of tsunamis in Wallis and Futuna, Southwest Pacific

2015 ◽  
Vol 3 (4) ◽  
pp. 2283-2346 ◽  
Author(s):  
G. Lamarche ◽  
S. Popinet ◽  
B. Pelletier ◽  
J. Mountjoy ◽  
J. Goff ◽  
...  
Keyword(s):  
Numerical Models ◽  
Plate Boundary ◽  
South Pacific ◽  
Tsunami Hazard ◽  
Time Of Arrival ◽  
Barrier Reef ◽  
Outer Reef ◽  
Southwest Pacific ◽  
The North ◽  
The Impact

Abstract. We investigated the tsunami hazard in the remote French territory of Wallis and Futuna, Southwest Pacific, using the Gerris flow solver to produce numerical models of tsunami generation, propagation and inundation. Wallis consists of the inhabited volcanic island of Uvéa that is surrounded by a lagoon delimited by a barrier reef. Futuna and the island of Alofi forms the Horn Archipelago located ca. 240 km east of Wallis. They are surrounded by a narrow fringing reef. Futuna and Alofi emerge from the North Fiji Transform Fault that marks the seismically active Pacific-Australia plate boundary. We generated fifteen tsunami scenarios. For each, we calculated maximum wave elevation (MWE), inundation distance, and Expected Time of Arrival (ETA). The tsunami sources were local, regional and distant earthquake faults located along the Pacific Rim. In Wallis, the outer reef may experience 6.8 m-high MWE. Uvéa is protected by the barrier reef and the lagoon, but inundation depths of 2–3 m occur in several coastal areas. In Futuna, flow depths exceeding 2 m are modelled in several populated areas, and have been confirmed by a post-September 2009 South Pacific tsunami survey. The channel between the islands of Futuna and Alofi amplified the 2009 tsunami, which resulted in inundation distance of almost 100 m and MWE of 4.4 m. This first-ever tsunami hazard modelling study of Wallis and Futuna compares well with palaeotsunamis recognised on both islands and observation of the impact of the 2009 South Pacific tsunami. The study provides evidence for the mitigating effect of barrier and fringing reefs from tsunamis.

scholarly journals Tsunami run-up estimation based on a hybrid numerical flume and a parameterization of real topobathymetric profiles

2017 ◽  
Author(s):  
Íñigo Aniel-Quiroga ◽  
Omar Quetzalcóatl ◽  
Mauricio González ◽  
Louise Guillou
Keyword(s):  
Numerical Models ◽  
Fluid Model ◽  
Coupled Model ◽  
Tsunami Hazard ◽  
Water Model ◽  
Tsunami Waves ◽  
Small Areas ◽  
Prone Area ◽  
Run Up ◽  
Tsunami Run Up

Abstract. Tsunami run-up is a key value to determine when calculating and assessing the tsunami hazard in a tsunami-prone area. Run-up is accurately calculated by means of numerical models, but these models require high-resolution topobathymetric data, which are not always available, and long computational times. These drawbacks restrict the application of these models to the assessment of small areas. As an alternative method, to address large areas, empirical formulae are commonly applied to estimate run-up. These formulae are based on numerical or physical experiments on idealized geometries. In this paper, a new methodology is presented to calculate tsunami hazard at large scales. This methodology determines the tsunami flooding by using a coupled model that combines a nonlinear shallow water model (2D-H) and a volume-of-fluid model (RANS 2D-V) and applies the optimal numerical scheme in each phase of the tsunami generation-propagation-inundation process. The hybrid model has been widely applied to build a tsunami run-up database (TRD). The aim of this database is to form an interpolation domain with which to estimate the tsunami run-up of new scenarios without running a numerical simulation. The TRD was generated by simulating the propagation of parameterized tsunami waves on real non-scaled profiles. A database and hybrid numerical model were validated using real and synthetic scenarios. The new methodology provides feasible estimations of the tsunami run-up; engineers and scientists can use this methodology to address tsunami hazard at large scales.

scholarly journals TSUNAMI HAZARD ASSESSMENT IN THE CASPIAN SEA

2019 ◽  
Vol 47 (5) ◽  
pp. 74-88
Author(s):  
E. A. Kulikov ◽  
A. Yu. Medvedeva ◽  
I. V. Fine
Keyword(s):  
Hazard Assessment ◽  
Caspian Sea ◽  
Water Area ◽  
Tsunami Hazard ◽  
Estimation Of Parameters ◽  
The Caspian Sea ◽  
Tsunami Waves ◽  
The North ◽  
Tsunami Hazard Assessment ◽  
Run Up

The article describes the tsunami hazard assessment for the coast of the Caspian Sea, in particular for the Absheron Peninsula. Due to the high socio-economic load on the coast of this region by electric power and oil production industries requirements, it is necessary to take into account risks even for such extremely rare natural phenomena like tsunamis. An earthquake with M = 8 ± 0.2 can occur throughout the Caspian Sea region, including land, once every 216 years, while for the water area the frequency of occurrence of such an event is 1620 years. The article presents the results of a tsunami hazard assessment based on a deterministic approach for the Absheron Peninsula. This approach of the tsunami hazard assessing of an arbitrary part of the coast consists of selecting of the strongest observed (or hypothetical) tsunami event from a neighborhood and from a distant zone, of the subsequent estimation of parameters for model sources and, finally, of the numerical modeling of tsunami generation and propagation from these sources. It was obtained that with the propagation of tsunami waves from the north to the coast of the Absheron Peninsula, its height can reach 3‒4 m for some parts of the coast with run-up 500‒1500 m.

scholarly journals Reconstructing Flood Events in Mediterranean Coastal Areas Using Different Reanalyses and High-Resolution Meteorological Models

2020 ◽  
Vol 21 (8) ◽  
pp. 1865-1887
Author(s):  
A. Senatore ◽  
S. Davolio ◽  
L. Furnari ◽  
G. Mendicino
Keyword(s):  
High Resolution ◽  
Climate Models ◽  
Hydrological Model ◽  
Numerical Models ◽  
Heavy Precipitation ◽  
High Impact ◽  
Added Value ◽  
Distributed Hydrological Model ◽  
The Impact ◽  
Small Catchments

AbstractReliable reanalysis products can be exploited to drive mesoscale numerical models and generate high-resolution reconstructions of high-impact weather events. Within this framework, regional weather and climate models may greatly benefit from the recent release of the ERA5 product, an improvement to the ERA-Interim dataset. In this study, two different convection-permitting models driven by these two reanalysis datasets are used to reproduce three heavy precipitation events affecting a Mediterranean region. Moreover, different sea surface temperature (SST) initializations are tested to assess how higher-resolution SST fields improve the simulation of high-impact events characterized by strong air–sea interactions. Finally, the coupling with a distributed hydrological model allows evaluating the impact at the ground, specifically assessing the possible added value of the ERA5 dataset for the high-resolution simulation of extreme hydrometeorological events over the Calabria region (southern Italy). Results, based on the comparison against multiple-source precipitation observations, show no clear systematic benefit to using the ERA5 dataset; moreover, intense convective activity can introduce uncertainties masking the signal provided by the boundary conditions of the different reanalyses. The effect of the high-resolution SST fields is even more difficult to detect. The uncertainties propagate and amplify along the modeling chain, where the spatial resolution increases up to the hydrological model. Nevertheless, even in very small catchments, some of the experiments provide reasonably accurate results, suggesting that an ensemble approach could be suitable to cope with uncertainties affecting the overall meteo-hydrological chain, especially for small catchments.

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