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Overview map around Cotopaxi volcano, showing exposed elements (human settlements, roads, airports), the hazard scenario used throughout this study (isomass map for an ERS of VEI 4-50 % probability of occurrence; Biass and Bonadonna, this volume) and the topographic context. The population density is inferred from the LandScan 2005 dataset. This area of Ecuador is divided into three regions: (i) La Sierra (central, orange), (ii) La Costa (west, purple) and (iii) La Amazonia (east, green)
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In order to develop efficient strategies for risk mitigation and emergency management, planners require the assessment of both the expected hazard (frequency and magnitude) and the vulnerability of exposed elements. This paper presents a GIS-based methodology to produce qualitative to semi-qualitative thematic risk assessments for tephra fallout ar...
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Context 1
... to tephra fallout able to combine geological and geographical datasets of varying precision and scales. Where the method is not able to quantify the expected losses, it still provides qualitative indications of the potential impact of tephra fallout. As an example, this strategy was applied to the area located around Cotopaxi volcano, Ecuador (Fig. ...
Context 2
... In order to present the method in a concise way, this paper illustrates two vulnerability themes (i.e. economic and physical) with one medium intensity eruptive scenario. The eruptive scenario chosen as an example is an ERS for VEI 4, with plume heights and erupted masses varying between 15 and 30 km and 1 -10 9 10 11 kg, respectively (Fig. 1). Hazard maps for all eruption scenarios can be found in Online Resource 1 of Biass and Bonadonna (this volume). Vulnerability and risk maps for all eruption scenarios and vulnerability themes are available in Online Resource 1 and 2 of this ...
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... resulting risk maps show a higher risk in administrative units located in the proximal and downwind areas and decreases away from the vent (Fig. 3b), which do not contain high densities of population (Fig. 1). Figure 3b is the resulting physical risk map considering an ERS of VEI 4 where the two closest parishes (Mulalo and Machachi) have values of building collapse of 2246 and 6221, respectively, corresponding to a loss of 100 % of the buildings in both cases. Physical risk maps for all eruptive scenarios are shown in the Online Resource ...
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... developed a method for a fast and remote qualitative assessment of the vulner- ability and the risk related to tephra fallout. The methodology was applied to Cotopaxi volcano, for which a thorough hazard assessment is described in Biass and Bonadonna (this volume). In this paper, we propose the use of isomass maps for a given probability (e.g. Fig. 1) when combining probabilistic hazard modelling and vulnerability assessments. In fact, isomass maps for given probability levels (e.g. 50 %) make the evaluation of the exposure clearer to decision-makers and the identification of the potential losses faster for governments. The acceptable levels of risk required to compile isomass maps ...
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... Areas between * 300 and * 18,000 km 2 (ERS for VEIs 3 and 5, respectively) could be affected by an accumulation of tephra of 10 kg/m 2 (about 1 cm). As shown in Fig. 1, the area most likely to be impacted is located west of the volcano, along the direction of prevailing winds, with consequences on (1) the important Panamerican Highway, which connects the Southern towns and cities of the Interandean valley to Quito and (2) the rural areas located around the town of Latacunga. The tephra threshold of ...
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Citations
... The use of GIS during post-disaster reconstruction (PDR) not only supports community participation and stakeholder engagement (Ali et al. 2020, Tafti andTomlinson 2015) but also facilitates emergency response planning (Dunn and Gonzalez-Otalora 2021) and provides timely and reliable information on infrastructure damages (Qi et al. 2021). Furthermore, GIS and remote sensing play a crucial role in conducting effective risk and vulnerability assessments, as well as implementing mitigation strategies (Biass et al. 2012, Mahmood et al. 2019. GIS also contributes to the improvement of land use patterns, offering opportunities to reduce vulnerabilities and enhance the design of the built environment (Gigović et al. 2017, Yau et al. 2014. ...
... Travel time or access penalties have been used to explore road vulnerability to volcanic hazards (e.g. Biass et al. 2012;Mossoux et al. 2019), whereby a hazard or impact threshold is used to reduce the functionality of a road. Scoring systems (such as those used in some index models to combine different types of vulnerability) have also been used to identify potential network disruption hotspots or to provide an overall score of system functionality for comparison across volcanoes, eruption scenarios or hazards (Galderisi et al. 2013;Bonadonna et al. 2021;Nieto-Torres et al. 2021;Hayes et al. 2022). ...
... Landslide risk assessments are complex tasks which involve geographic data of large areas of surface such as: land use, road network, human settlements, topography, temporal data, wind speed and patterns and variation in population density. Such data can come from diverse sources (El Morjani et al., 2007;Biass et al., 2013). The main limitations of the application of geo-informatics are: (1) the high demand and cost of data, (2) the need for multivariate / multi-format analysis, (3) the need for frequent updates of said data, and (4) databases and parameters relevant to the assessment of social vulnerability are difficult to map (Ebert et al., 2009). ...
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... Copyright Iste 2022 / File for personal use of Alessandro Tadini only isomass maps involves the same considerations as for isopach maps, and isomass maps could also be used to obtain the dispersion axis and the dispersal area (see previous section). Mass loading is an important parameter for defining the stability of roofs under tephra load and for determining mass loading threshold values that impact different elements at risk (Biass et al. 2013), both in real time (syn-eruptive conditions) and for long-term hazard and risk studies (post-eruptive conditions). ...
“Pyroclastic fallout” is the process of fallout of the particles, which is one of the most common processes in volcanology and is generally associated with all types of explosive eruptions. This chapter shows how the study and monitoring of pyroclastic fallout products play a key role in volcanic risk assessment. The pyroclastic fallout process is, in its simplest formulation, the sedimentation of pyroclasts through the atmosphere and their deposition on the Earth's surface. For fallout deposits, the subdivision into proximal, medial or distal deposits depends on the size of the eruption considered. During eruptive crises a sampling of the eruptive products is generally carried out in the hours following the beginning of each eruption. Geochemical and petrographic analysis of pyroclasts can constrain the initial conditions from the magma chamber to the surface via the conduit. Total grain size distribution represents the theoretical eruptive mixture injected into the atmosphere during volcanic explosive eruptions.
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... Le processus de dérivation des cartes d'isomasse implique les mêmes considérations que pour les cartes d'isopaque, et les cartes d'isomasse pourraient également être utilisées pour obtenir l'axe et la zone de dispersion (voir la section précédente). La charge massique est un paramètre important pour définir la stabilité des toitures sous l'effet des retombées et pour déterminer les valeurs seuils de la charge massique qui impactent différents éléments à risque (Biass et al. 2013), à la fois en temps réel (conditions syn-éruptives) et pour les études à long terme sur les dangers et les risques (conditions post-éruptives). ...
Des téphras (ou pyroclastites) couvrant une large gamme de granulométries sont éjectés par tous les types d'éruptions. Ils engendrent de nombreux aléas. Leurs retombées peuvent être étudiés après, mais aussi durant, les éruptions. Les techniques d'étude ont beaucoup évolué et sont devenues plus quantitatives. Ceci donne accès à un nombre croissant d'informations sur les mécanismes et la dynamique des éruptions. Ce chapitre décrit les approches modernes de ces études.
Tephras (or pyroclastites) covering a wide range of grain sizes are ejected by all types of eruptions. They generate many hazards. Their fallout can be studied after, but also during, the eruptions. Study techniques have evolved a lot and have become more quantitative. This gives access to a growing amount of information on the mechanisms and dynamics of eruptions. This chapter describes modern approaches to such studies.
... Copyright Iste 2022 / File for personal use of Alessandro Tadini only isomass maps involves the same considerations as for isopach maps, and isomass maps could also be used to obtain the dispersion axis and the dispersal area (see previous section). Mass loading is an important parameter for defining the stability of roofs under tephra load and for determining mass loading threshold values that impact different elements at risk (Biass et al. 2013), both in real time (syn-eruptive conditions) and for long-term hazard and risk studies (post-eruptive conditions). ...
... These volcanoes showed different eruptive styles and eruption durations and led to different impacts on the population: Guagua Pichin-cha's eruption mainly resulted in ashfall on the capital city of Quito and the consequences (especially on the younger population) lasted for a few months [Naumova et al. 2007]; Tungurahua's eruption lasted 16 years with explosions that occasionally caused significant ash emissions and pyroclastic density currents (PDC) that impacted local communities in various forms [Few et al. 2017]; El Reventador and Sangay volcanoes continue to erupt almost without interruption to this day, with outbursts of explosions and small to medium PDCs and a relatively rapid landscape change [Ortiz et al. 2021;Valverde et al. 2021]; Cotopaxi volcano's brief reactivation in 2015 lasted for a few months with a paroxysm with a volcano explosivity index (VEI) of 2 and a lowlevel ash plume that caused social distress in nearby (∼14 km) communities [Hidalgo et al. 2018;Gomez-Zapata et al. 2021]. The high spatial density of active Holocene volcanoes and associated volcanic hazards has impacted pre-Columbian populations [Isaacson and Zeidler 1999;Hall and Mothes 2008;Vallego Vargas 2011;Le Pennec 2013] and continues to impact contemporary populations Biass et al. 2012;Le Pennec et al. 2012] in the region. Population growth, particularly in the large urban centres of the Inter-Andean Valley [Villacís et al. 2011], is increasing exposure to volcanic hazards and thus there is a need for more effective and continuously evolving hazard and risk communication, especially with vulnerable communities. ...
Hazard and risk communication requires the design and dissemination of clear messages that enhance people's actions before, during, and after volcanic crises. To create effective messages, the communication components such as message format and content, must be considered. Changes in technology are changing the way people communicate at an ever-increasing pace; thus, we propose revising the basic components of the communication process to improve the dialogue between scientists and the public. We describe communication issues during and outside volcanic crises in Ecuador and assess possible causes and consequences. These ideas were discussed during the short-duration "Volcano Geophysical Principles and Hazards Communications" Workshop in Baños, Ecuador in 2019. We review and propose communication strategies for volcanic hazards and risks that resulted from the workshop discussions and experiences of experts from the Instituto Geofísico (IG-EPN), local and international professors involved in volcano research and communication, and students from universities across Ecuador.
... The data needed to fully analyse volcanic risks are often insufficiently or inaccurately catalogued or even totally lacking, while it is also true that the risks are dynamic and constantly shifting during volcanic unrest, eruption and after the eruption [63]. In addition, no comprehensive methods for vulnerability and risk assessment are widely accepted and, while some models identify individual interactions between the volcanic hazards and physical vulnerability [64][65][66], the limited analyses on the multiple dimensions of vulnerabilities obscures our understanding of the real volcanic risks [67]. ...
Muography uses muons naturally produced in the interactions between cosmic rays and
atmosphere for imaging and characterization of density differences and time-sequential
changes in solid (e.g. rocks) and liquid (e.g. melts±dissolved gases) materials in scales from tens of metres to up to a few kilometres. In addition to being useful in discovering the secrets of the pyramids, ore prospecting and surveillance of nuclear sites, muography successfully images the internal structure of volcanoes. Several field campaigns have demonstrated that muography can image density changes relating to magma ascent and descent, magma flow rate, magma degassing, the shape of the magma body, an empty conduit diameter, hydrothermal activity and major fault lines. In addition, muography is applied for long-term volcano monitoring in a few selected volcanoes around the world. We propose using muography in volcano monitoring in conjunction with other existing techniques for predicting volcanic hazards. This approach can provide an early indication of a possible future eruption and potentially the first estimate of its scale by producing direct evidence of magma ascent through its conduit in real time. Knowing these issues as early as possible buy critically important time for those responsible for the local alarm and evacuation protocols.
... Bonadonna et al. 2018), the integration of hazard and vulnerability assessments for a comprehensive evaluation of risk remains elusive. Pioneering works in quantitative risk assessment include the analyses of Spence et al. (2005), Biass et al. (2012Biass et al. ( , 2016aBiass et al. ( , 2016bBiass et al. ( , 2017, Scaini et al. (2014) and Thompson et al. (2016) for tephra fallout, Alberico et al. (2008) for pyroclastic density currents (PDCs), Bonne et al. (2008) and Favalli et al. (2009) for lava flows, and Lavigne (2000), Leung et al. (2003), and Mead and Magill (2017) for lahars. In addition, some examples of multi-hazard risk assessment also exist (e.g. ...
... Nonetheless, such a distribution of hazard intensity can be based on a probabilistic analysis addressing the epistemic and aleatoric uncertainties associated with the choice of eruptive scenarios (e.g. probabilistic isomass maps; Biass et al. 2012). ...
Risk assessments in volcanic contexts are complicated by the multi-hazard nature of both unrest and eruption phases, which frequently occur over a wide range of spatial and temporal scales. As an attempt to capture the multi-dimensional and dynamic nature of volcanic risk, we developed an integrAteD VolcanIc risk asSEssment (ADVISE) model that focuses on two temporal dimensions that authorities have to address in a volcanic context: short-term emergency management and long-term risk management. The output of risk assessment in the ADVISE model is expressed in terms of potential physical, functional, and systemic damage, determined by combining the available information on hazard, exposed systems and vulnerability. The ADVISE model permits qualitative, semi-quantitative and quantitative risk assessment depending on the final objective and on the available information. The proposed approach has evolved over a decade of study on the volcanic island of Vulcano (Italy), where recent signs of unrest combined with uncontrolled urban development and significant seasonal variations of exposed population result in highly dynamic volcanic risk. For the sake of illustration of all the steps of the ADVISE model, we focus here on the risk assessment of the transport system in relation to the tephra fallout associated with a long-lasting Vulcanian cycle.
Supplementary information:
The online version contains supplementary material available at 10.1186/s13617-021-00108-5.
