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| Titel |
A simple semi-empirical approach to model thickness of ash-deposits for different eruption scenarios |
| VerfasserIn |
A. O. González-Mellado, S. Cruz-Reyna |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 10, no. 11 ; Nr. 10, no. 11 (2010-11-08), S.2241-2257 |
| Datensatznummer |
250008495
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| Publikation (Nr.) |
 copernicus.org/nhess-10-2241-2010.pdf |
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| Zusammenfassung |
The impact of ash-fall on people, buildings, crops, water resources, and
infrastructure depends on several factors such as the thickness of the
deposits, grain size distribution and others. Preparedness against tephra
falls over large regions around an active volcano requires an understanding
of all processes controlling those factors, and a working model capable of
predicting at least some of them. However, the complexity of tephra
dispersion and sedimentation makes the search of an integral solution an
almost unapproachable problem in the absence of highly efficient computing
facilities due to the large number of equations and unknown parameters that
control the process. An alternative attempt is made here to address the
problem of modeling the thickness of ash deposits as a primary impact factor
that can be easily communicated to the public and decision-makers. We develop
a semi-empirical inversion model to estimate the thickness of non-compacted
deposits produced by an explosive eruption around a volcano in the distance
range 4–150 km from the eruptive source.
The model was elaborated from the analysis of the geometric distribution of
deposit thickness of 14 world-wide well-documented eruptions. The model was
initially developed to depict deposits of potential eruptions of
Popocatépetl and Colima volcanoes in México, but it can be applied to
any volcano. It has been designed to provide planners and Civil Protection
authorities of an accurate perception of the ash-fall deposit thickness that
may be expected for different eruption scenarios. The model needs to be fed
with a few easy-to-obtain parameters, namely, height of the eruptive column,
duration of the explosive phase, and wind speed and direction, and its
simplicity allows it to run in any platform, including a personal computers
and even a notebook. The results may be represented as tables, two
dimensional thickness-distance plots, or isopach maps using any available
graphic interface. The model has been tested, with available data from some
recent eruptions in México, and permits to generate ash-fall deposit
scenarios from new situations, or to recreate past situations, or to
superimpose scenarios from eruptions of other volcanoes. The results may be
displayed as thickness vs. distance plots, or as deposit-thickness scenarios
superimposed on a regional map by means of a visual computer simulator based
on a user-friendly built-in computer graphic interface. |
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