Brief Communication &amp;quot;Rain effect on the load of tephra deposits&amp;quot;

Macedonio, Giovanni; Costa, Antonio

doi:10.5194/nhess-12-1229-2012

Cited by 42 publications

(45 citation statements)

References 10 publications

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“…An estimation of the contribution of the rain to the deposit load, applied to the pyroclastic deposits in the Neapolitan area was considered by Macedonio and Costa (2012) that account for the statistics of the rains in the Neapolitan area (Fiorillo and Wilson 2004;Macedonio and Costa 2012). In order to estimate the maximum tephra load, Macedonio and Costa (2012) assumed that the deposit absorbs all the water up to the limit of remobilization or up to the maximum available water. In the latter case, they considered the maximum events of rain in the Neapolitan area during the last century (about 200 mm of rain per month, and the extreme event of 500 mm).…”

Section: Discussionmentioning

confidence: 99%

Effects of eruption source parameter variation and meteorological dataset on tephra fallout hazard assessment: example from Vesuvius (Italy)

et al. 2016

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In this study, using the tephra dispersal model HAZMAP, we investigate the effect of using different meteorological datasets and eruption source parameters on tephra fallout hazard assessment for a sub-Plinian eruption of Vesuvius, which is considered as a reference case for hazard assessment analysis. We analyze the effect of using different meteorological data, from: i) radio-sounding carried out at the meteorological station of Brindisi (Italy) between 1962 and 1976 and between 1996 and 2012, and at Pratica di Mare (Rome, Italy) between 1995 and 2013; ii) meteorological models of the National Oceanic and Atmospheric Administration (NOAA), and of the European Centre for Medium-Range Weather Forecasts (ECMWF). Furthermore, we consider the effects of perturbing reference eruptive source parameters. In particular, we vary the total mass, the total grain-size distribution, the column height, and the effective atmospheric diffusion coefficient to evaluate how these parameters affect the hazard probability maps. Moreover, the effect of the seasonal variation of the wind field and the effect of the rain on the deposit loading are considered. Results show that the parameter that mostly affects hazard maps is, as expected, the total erupted mass; furthermore, keeping constant the erupted mass, the most important control on hazard is due to the particle terminal settling velocity distribution which is a function of the total grain-size distribution, particle density and shape. Within the considered range variations, the hazard depends less on the use of different meteorological datasets, column height and effective diffusion coefficient.

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Section: Discussionmentioning

confidence: 99%

Effects of eruption source parameter variation and meteorological dataset on tephra fallout hazard assessment: example from Vesuvius (Italy)

et al. 2016

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“…This hazard can, in turn, be modified by the adsorption of water within the porosity of the tephra deposit resulting from rainfall. Macedonio and Costa (2012) formalized a simple approach to estimate the additional water load based on the saturation of the total porosity. Following the values proposed by Fiorillo and Wilson (2004) for the Vesuvius region, we use total porosities of 0.67 and 0.68 for Vulcanian and sub-Plinian deposits, respectively.…”

Section: Impact Of Rainfallmentioning

confidence: 99%

Probabilistic evaluation of the physical impact of future tephra fallout events for the Island of Vulcano, Italy

et al. 2016

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A first probabilistic scenario-based hazard assessment for tephra fallout is presented for La Fossa volcano (Vulcano Island, Italy) and subsequently used to assess the impact on the built environment. Eruption scenarios are based upon the stratigraphy produced by the last 1000 years of activity at Vulcano and include long–lasting Vulcanian and sub-Plinian eruptions. A new method is proposed to quantify the evolution through time of the hazard associated with pulsatory Vulcanian eruptions lasting from weeks to years, and the increase in hazard related to typical rainfall events around Sicily is also accounted for. The impact assessment on the roofs is performed by combining a field characterization of the buildings with the composite European vulnerability curves for typical roofing stocks. Results show that a sub-Plinian eruption of VEI 2 is not likely to affect buildings, whereas a sub-Plinian eruption of VEI 3 results in 90 % of the building stock having a ≥12 % probability of collapse. The hazard related to long-lasting Vulcanian eruptions evolves through time, and our analysis shows that the town of Il Piano, located downwind of the preferential wind patterns, is likely to reach critical tephra accumulations for roof collapse 5–9 months after the onset of the eruption. If no cleaning measures are taken, half of the building stock has a probability >20 % of suffering roof collapse

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“…All these studies emphasise the need to focus on static load rather than ash thickness as wet and dry densities of ash can vary widely from about 500 to 2000 kg/m 3 (Shipley, S.and Sarna-Wojcicki, A 1982;Blong 1984;Spence et al 2005;Macedonio & Costa 2012;Jenkins et al 2014).…”

Section: Building Vulnerability To Ash Fallmentioning

confidence: 99%

“…This is important as wet ash can achieve bulk densities and ash loads about double that of dry ash (cf. Blong, 2003;Macedonio and Costa 2012). Figure 1 shows vulnerability functions for eight building types based on the combined and considered view of all 'experts' present at the Geoscience Australia GAR workshop.…”

Section: Building Vulnerability To Ash Fallmentioning

confidence: 99%

Estimating building vulnerability to volcanic ash fall for insurance and other purposes

Blong¹,

Grasso²,

Jenkins

et al. 2017

J Appl. Volcanol.

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Volcanic ash falls are one of the most widespread and frequent volcanic hazards, and are produced by all explosive volcanic eruptions. Ash falls are arguably the most disruptive volcanic hazard because of their ability to affect large areas and to impact a wide range of assets, even at relatively small thicknesses. From an insurance perspective, the most valuable insured assets are buildings. Ash fall vulnerability curves or functions, which relate the magnitude of ash fall to likely damage, are the most developed for buildings, although there have been important recent advances for agriculture and infrastructure. In this paper, we focus on existing vulnerability functions developed for volcanic ash fall impact on buildings, and apply them to a hypothetical building portfolio impacted by a modernday Tambora 1815 eruption scenario. We compare and contrast the different developed functions and discuss some of the issues surrounding estimation of potential building damage following a volcanic eruption. We found substantial variability in the different vulnerability estimates, which contribute to large uncertainties when estimating potential building damage and loss. Given the lack of detailed and published studies of building damage resulting from ash fall this is not surprising, although it also appears to be the case for other natural hazards for which there are far more empirical damage data. Notwithstanding the potential limitations of some empirical data in constraining vulnerability functions, efforts are required to improve our estimates of building damage under ash fall loading through the collection of damage data, experimental testing and perhaps theoretical failure analysis. For insurance purposes, the current building typologies provided for use with vulnerability functions are too detailed to map to the relatively limited information on building types that is typically available to insurers. Thus, efforts to provide vulnerability functions that can be used where only limited information is available regarding building types would also be valuable, both for insurers and for at-risk areas that have not been subject to detailed building vulnerability surveys.

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Brief Communication "Rain effect on the load of tephra deposits"

Cited by 42 publications

References 10 publications

Effects of eruption source parameter variation and meteorological dataset on tephra fallout hazard assessment: example from Vesuvius (Italy)

Effects of eruption source parameter variation and meteorological dataset on tephra fallout hazard assessment: example from Vesuvius (Italy)

Probabilistic evaluation of the physical impact of future tephra fallout events for the Island of Vulcano, Italy

Estimating building vulnerability to volcanic ash fall for insurance and other purposes

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