scholarly journals Thematic vent opening probability maps and hazard assessment of small-scale pyroclastic density currents in the San Salvador Volcanic Complex (El Salvador) and Nejapa-Chiltepe Volcanic Complex (Nicaragua)

2020 ◽  
Author(s):  
Andrea Bevilacqua ◽  
Alvaro Aravena ◽  
Augusto Neri ◽  
Eduardo Gutiérrez ◽  
Demetrio Escobar ◽  
...  
Keyword(s):  
El Salvador ◽  
Small Scale ◽  
Volcanic Complex ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Thematic Maps ◽  
Eruption Style ◽  
San Salvador ◽  
Low Intensity ◽  
Probability Maps

Abstract. San Salvador Volcanic Complex (El Salvador) and Nejapa-Chiltepe Volcanic Complex (Nicaragua) have been characterized by a significant variability in eruption style and vent location. Densely inhabited cities are in their surroundings, including the metropolitan areas of San Salvador (~2.4 M people) and Managua (~1.4 M people), respectively. In this study we present novel vent opening probability maps for these volcanic complexes, which are based on a multi-model approach that relies on kernel density estimators. Our volcanological dataset includes: (1) the location of past vents, (2) the mapping of the main fault structures, and (3) the eruption styles of past events, obtained from the critical analysis of literature and/or inferred from volcanic deposits and morphological features observed remotely and in the field. In particular, we present thematic vent opening maps, i.e. we consider different hazardous phenomena separately, including lava emission, small-scale pyroclastic density currents, ejection of ballistic projectiles, and low-intensity pyroclastic fallout. To illustrate the effects of considering the expected eruption style in the construction of vent opening maps, we focus on the analysis of small-scale pyroclastic density currents derived from phreatomagmatic activity or from low-intensity magmatic volcanism. For the numerical simulation of these phenomena we adopted the recently developed branching energy cone model by using the program ECMapProb. Our results show that the implementation of thematic maps of vent opening can produce significantly different hazard levels from those estimated with traditional, non-thematic, maps.

scholarly journals Thematic vent opening probability maps and hazard assessment of small-scale pyroclastic density currents in the San Salvador volcanic complex (El Salvador) and Nejapa-Chiltepe volcanic complex (Nicaragua)

2021 ◽  
Vol 21 (5) ◽  
pp. 1639-1665
Author(s):  
Andrea Bevilacqua ◽  
Alvaro Aravena ◽  
Augusto Neri ◽  
Eduardo Gutiérrez ◽  
Demetrio Escobar ◽  
...  
Keyword(s):  
El Salvador ◽  
Small Scale ◽  
Volcanic Complex ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Eruption Style ◽  
San Salvador ◽  
Low Intensity ◽  
Probability Maps ◽  
Cone Model

Abstract. The San Salvador volcanic complex (El Salvador) and Nejapa-Chiltepe volcanic complex (Nicaragua) have been characterized by a significant variability in eruption style and vent location. Densely inhabited cities are built on them and their surroundings, including the metropolitan areas of San Salvador (∼2.4 million people) and Managua (∼1.4 million people), respectively. In this study we present novel vent opening probability maps for these volcanic complexes, which are based on a multi-model approach that relies on kernel density estimators. In particular, we present thematic vent opening maps, i.e., we consider different hazardous phenomena separately, including lava emission, small-scale pyroclastic density currents, ejection of ballistic projectiles, and low-intensity pyroclastic fallout. Our volcanological dataset includes: (1) the location of past vents, (2) the mapping of the main fault structures, and (3) the eruption styles of past events, obtained from critical analysis of the literature and/or inferred from volcanic deposits and morphological features observed remotely and in the field. To illustrate the effects of considering the expected eruption style in the construction of vent opening maps, we focus on the analysis of small-scale pyroclastic density currents derived from phreatomagmatic activity or from low-intensity magmatic volcanism. For the numerical simulation of these phenomena we adopted the recently developed branching energy cone model by using the program ECMapProb. Our results show that the implementation of thematic vent opening maps can produce significantly different hazard levels from those estimated with traditional, non-thematic maps.

scholarly journals Scenario-Based Pyroclastic Density Current Invasion Maps at Poorly Known Volcanoes: A Case Study from Changbaishan (China/North Korea)

2020 ◽  
Vol 10 (7) ◽  
pp. 2622
Author(s):  
Anna Maria Lombardi ◽  
Pierdomenico Del Gaudio ◽  
Zhengfu Guo ◽  
Maoliang Zhang ◽  
Guoming Liu ◽  
...  
Keyword(s):  
North Korea ◽  
Density Current ◽  
Rapid Evaluation ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Eruptive History ◽  
Probability Maps ◽  
Changbaishan Volcano ◽  
Global Datasets

Changbaishan volcano (China/North Korea; last eruption in 1903 AD) was responsible for a Volcanic Explosivity Index (VEI) 7 eruption in 946 AD. Approximately 186,000 people live around Changbaishan and 2,000,000 tourists/year visit the volcano. An unrest occurred between 2002 and 2006. Despite the relevant hazard, the eruptive history is poorly known, a condition common to many volcanoes worldwide. Here, we investigate the extension of the areas potentially affected by pyroclastic density currents (PDCs) in case of future eruptions following a scenario-based approach. We perform energy cone runs referred to four scenarios from columns of height 3, 10, 20 and 30 km at different vents. By using global datasets on PDCs, we produce spatial probability maps of PDCs invasion. Empirical laws between covered areas, PDC travelled distances, and heights of collapse are provided. In scenarios 3 and 4, PDCs expand at distances up to 42 km and 85 km, respectively. In scenarios 1 and 2, PDCs invade the touristic area and few main roads. Severe effects emerge from scenarios 3 and 4 with the interruption of the China–North Korea land and aerial connections and PDC. Our approach may serve as guide for the rapid evaluation of the PDC-related hazard at poorly known volcanoes.

scholarly journals Volcanic monitoring and hazard assessment in El Salvador

Volcanica ◽  
2021 ◽  
Vol 4 (S1) ◽  
pp. 183-201
Author(s):  
Rodolfo Antonio Castro Carcamo ◽  
Eduardo Gutiérrez
Keyword(s):  
El Salvador ◽  
Volcanic Hazard ◽  
Volcano Monitoring ◽  
Volcanic Complex ◽  
Civil Protection ◽  
Hazard Maps ◽  
Volcanic Arc ◽  
San Salvador ◽  
The Pacific ◽  
Volcanic Monitoring

The Salvadorean volcanic range forms part of Central America Volcanic Arc and is located on the Pacific ring of fire. El Salvador is a country with at least twenty Holocene-active volcanic structures and where most of the population, including the metropolitan area of San Salvador, live near a volcanic complex. Currently, there are six active volcanoes that are continuously monitored by the Observatorio de Amenazas y Recursos Naturales, which is part of the Ministerio del Medio Ambiente y Recursos Naturales. Volcano monitoring involves seismic, geochemical, and visual monitoring techniques, among others. In addition to volcano monitoring and with the aim of early warning of future eruptions, volcanic hazard maps and networks of local observers have been developed. These initiatives together with the general directorate of civil protection, seek to meet the goal of reducing risk from volcanic activity in El Salvador.  La cadena volcánica salvadoreña forma parte del Arco Volcánico de América Central y está localizada dentro de la zona conocida como cinturón de fuego del Pacífico. El Salvador es un país donde se encuentran al menos 20 estructuras volcánicas que han estado activas durante el Holoceno y donde la mayor parte de la población, incluyendo la ciudad capital San Salvador, está ubicada en las proximidades de algún complejo volcánico. Actualmente, seis volcanes activos son continuamente monitoreados por el Observatorio de Amenazas y Recursos Naturales, que es parte del Ministerio del Medio Ambiente y Recursos Naturales. El monitoreo volcánico se realiza mediante técnicas de monitoreo sísmicas, geoquímicas, visuales, entre otras. Como complemento del trabajo de monitoreo, se han desarrollado mapas de amenaza volcánica y redes de observadores locales constituyendo así sistemas de alerta temprana ante futuras erupciones. Estas iniciativas, en conjunto con la dirección general de la protección civil, persiguen el objetivo de reducir el riesgo por actividad volcánica en El Salvador.

scholarly journals Effectiveness of cartographic presentation methods applied within small-scale thematic maps in the press and on the Internet

2015 ◽  
Vol 47 (1) ◽  
pp. 5-17
Author(s):  
Jolanta Korycka-Skorupa
Keyword(s):  
Graphic Design ◽  
Small Scale ◽  
The Internet ◽  
Thematic Maps ◽  
The Press ◽  
Presentation Methods ◽  
Written Word ◽  
Selection Of ◽  
Better Than

Abstract The author discuss effectiveness of cartographic presentations. The article includes opinions of cartographers regarding effectiveness, readability and efficiency of a map. It reminds the principles of map graphic design in order to verify them using examples of small-scale thematic maps. The following questions have been asked: Is the map effective? Why is the map effective? How do cartographic presentation methods affect effectiveness of the cartographic message? What else can influence effectiveness of a map? Each graphic presentation should be effective, as its purpose is to complete written word, draw the recipients’ attention, make text more readable, expose the most important information. Such a significant role of graphics results in the fact that graphic presentations (maps, diagrams) require proper preparation. Users need to have a chance to understand the graphics language in order to draw correct conclusions about the presented phenomenon. Graphics should demonstrate the most important elements, some tendencies, and directions of changes. It should generalize and present a given subject from a slightly different perspective. There are numerous examples of well-edited and poorly edited small-scale thematic maps. They include maps, which are impossible to interpret correctly. They are burdened with methodological defects and they cannot fulfill their task. Cartography practice indicates that the principles related to graphic design of cartographic presentation are frequently omitted during the process of developing small-scale thematic maps used – among others – in the press and on the Internet. The purpose of such presentations is to quickly interpret them. On such maps editors’ problems with the selection of an appropriate symbol and graphic variable (fig. 1A, 9B) are visible. Sometimes they use symbols which are not sufficiently distinguishable nor demonstrative (fig. 11), it does not increase their readability. Sometime authors try too hard to reflect presented phenomenon and therefore the map becomes more difficult to interpret (fig. 4A,B). The lack of graphic sense resulting in the lack of graphic balance and aesthetics constitutes a weak point of numerous cartographic presentations (fig. 13). Effectiveness of cartographic presentations consists of knowledge and skills of the map editor, as well as the recipients’ perception capabilities and their readiness to read and interpret maps. The qualifications of the map editor should include methodological qualifications supported by the knowledge of the principles for cartographic symbol design, as well as relevant technical qualifications, which allow to properly use the tools to edit a map. Maps facilitate the understanding of texts they accompany and they present relationships between phenomenon better than texts, appealing to the senses.

scholarly journals Development of a Nationwide, Low-Level Wind Shear Mosaic in France

2013 ◽  
Vol 28 (5) ◽  
pp. 1241-1260 ◽  
Author(s):  
Clotilde Augros ◽  
Pierre Tabary ◽  
Adrien Anquez ◽  
Jean-Marc Moisselin ◽  
Pascal Brovelli ◽  
...  
Keyword(s):  
Wind Shear ◽  
Propagation Speed ◽  
Horizontal Wind ◽  
Small Scale ◽  
Wind Gust ◽  
Density Currents ◽  
Use Of Data ◽  
Low Levels ◽  
Cell Propagation ◽  
Convective Cells

Abstract An algorithm for the detection of horizontal wind shear at low levels was developed. The algorithm makes use of data collected by all radars from the Application Radar à la Météorologie Infra-Synoptique (ARAMIS) operational network, in order to build a complete mosaic of wind shear over metropolitan France. The product provides an estimation of the maximum horizontal wind shear detected in the low levels, between 0 and 2 km AGL. Examination of the wind shear mosaic for different cases shows that the product is able to retrieve small-scale wind shear signatures that can be linked to either convergence lines ahead of convective cells, which are indicative of gust fronts, or strong convergence areas inside intense cells. A statistical evaluation of the wind shear mosaic was performed, by comparing horizontal wind shear observed inside the area defined by convective objects with wind gusts recorded along their trajectory by weather stations. A link between those different observations was clearly established. Therefore, the use of wind shear for wind gust prediction was tested in combination with other parameters: an estimation of the energetic potential of density currents, the cell surface with reflectivity over 51 dBZ, relative helicity, and cell propagation speed. Different wind gust warning rules were tested on 468 convection nowcasting objects (CONOs). The results clearly highlighted the benefits of using wind shear for wind gust estimation, and also demonstrated the improvement in forecasting skill when combining different parameters. The wind shear mosaic will be produced operationally before the end of 2013 and will be used to improve wind gust warnings provided to end users.

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