Publication Date:
2017-04-04
Description:
Pyroclastic density currents (PDCs) are gravitydriven
hot mixtures of gas and volcanic particles which can
propagate at high speed and cover distances up to several tens
of kilometers around a given volcano. Therefore, they pose a
severe hazard to the surroundings of explosive volcanoes able
to produce such phenomena. Despite this threat, probabilistic
volcanic hazard assessment (PVHA) of PDCs is still in an
early stage of development. PVHA is rooted in the quantification
of the large uncertainties (aleatory and epistemic)
which characterize volcanic hazard analyses. This quantification
typically requires a big dataset of hazard footprints obtained
from numerical simulations of the physical process. For
PDCs, numerical models range from very sophisticated (not
useful for PVHA because of their very long runtimes) to very
simple models (criticized because of their highly simplified physics). We present here a systematic and robust validation
testing of a simple PDC model, the energy cone (EC), to
unravel whether it can be applied to PVHA of PDCs. Using
past PDC deposits at Somma-Vesuvius and Campi Flegrei
(Italy), we assess the ability of EC to capture the values and
variability in some relevant variables for hazard assessment,
i.e., area of PDC invasion and maximum runout. In terms of
area of invasion, the highest Jaccard coefficients range from
0.33 to 0.86 which indicates an equal or better performance
compared to other volcanic mass-flow models. The p values
for the observed maximum runouts vary from 0.003 to 0.44.
Finally, the frequencies of PDC arrival computed from the EC
are similar to those determined from the spatial distribution of
past PDC deposits, with high PDC-arrival frequencies over an
∼8-km radius from the crater area at Somma-Vesuvius and
around the Astroni crater at Campi Flegrei. The insights derived
from our validation tests seem to indicate that the EC is a
suitable candidate to compute PVHA of PDCs.
Description:
Published
Description:
79
Description:
3V. Dinamiche e scenari eruttivi
Description:
JCR Journal
Description:
restricted
Keywords:
Pyroclastic density currents
;
Probabilistic hazard assessment
;
Energy cone
;
Somma-Vesuvius
;
Campi Flegrei
;
04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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