Publication Date:
2017-04-04
Description:
Tephra fall is a relevant hazard of Campi Flegrei caldera (Southern Italy), due to the
high vulnerability of Naples metropolitan area to such an event. Here, tephra derive from
magmatic as well as phreatomagmatic activity. On the basis of both new and literature
data on known, past eruptions (Volcanic Explosivity Index (VEI), grain size parameters,
velocity at the vent, column heights and erupted mass), and factors controlling tephra
dispersion (wind velocity and direction), 2D numerical simulations of fallout dispersion
and deposition have been performed for a large number of case events. A bayesian
inversion has been applied to retrieve the best values of critical parameters (e.g., vertical
mass distribution, diffusion coefficients, velocity at the vent), not directly inferable by
volcanological study. Simulations are run in parallel on multiple processors to allow a
fully probabilistic analysis, on a very large catalogue preserving the statistical proprieties
of past eruptive history. Using simulation results, hazard maps have been computed for
different scenarios: upper limit scenario (worst-expected scenario), eruption-range
scenario, and whole-eruption scenario. Results indicate that although high hazard
characterizes the Campi Flegrei caldera, the territory to the east of the caldera center,
including the whole district of Naples, is exposed to high hazard values due to the
dominant westerly winds. Consistently with the stratigraphic evidence of nature of past
eruptions, our numerical simulations reveal that even in the case of a subplinian eruption
(VEI = 3), Naples is exposed to tephra fall thicknesses of some decimeters, thereby
exceeding the critical limit for roof collapse. Because of the total number of people
living in Campi Flegrei and the city of Naples (ca. two million of inhabitants), the tephra
fallout risk related to a plinian eruption of Campi Flegrei largely matches or exceeds
the risk related to a similar eruption at Vesuvius.
Description:
Published
Description:
B07203
Description:
4.3. TTC - Scenari di pericolosità vulcanica
Description:
JCR Journal
Description:
reserved
Keywords:
the Neapolitan area
;
Campi Flegrei eruptions
;
04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
