Living at the Edge of an Active Volcano: Risk from Lava Flows on Mount
Etna
Boulder, Colo., USA: On Mt. Etna volcano, inhabited areas have been
inundated repeatedly by lava flows in historical times. The increasing
exposure of a larger population, which has almost tripled in the area
around Mt. Etna during the last 150 years, has resulted from on a poor
assessment of the volcanic hazard and risk, allowing inappropriate land use
in vulnerable areas. Thus, the researchers of the Laboratory of
Technologies for Volcanology (TecnoLab) at the INGV in Catania assessed and
mapped hazard, exposure, and risk for providing a basic broad overview of
the potential effusive eruption impacts on the flanks of Mt. Etna.
Despite our knowledge of volcanic hazards and our capability to monitor
volcanic activity, the possibility that effusive eruptions of Etna volcano
could harm people, properties and services is greater today than ever
before. A 2013 analysis of lava flow hazards and their distribution around
the Etna volcano showed them to be far more dangerous than previously
expected. There is no compelling evidence to think that rates and
magnitudes of volcanism are changing, but, as a consequence of rising
population densities, increasingly sophisticated facilities, and expanding
complex social and economic infrastructure, all communities around Mt. Etna
are becoming more vulnerable to experiencing heavy consequences from
volcanic hazard activity.
The researchers of the TecnoLab assessed the lava flow risk on the flanks
of Mt. Etna by using a GIS-based approach that combines simply the hazard
with the exposure of elements at stake (the vulnerability was not
considered). The hazard, showing the long-term probability related to lava
flow inundation, was obtained by combining three different kinds of
information: the spatiotemporal probability of the future opening of new
flank eruptive vents, the event probability associated with classes of
expected eruptions, and the overlapping of lava flow paths simulated by the
MAGFLOW model. Data including all exposed elements were gathered from
institutional web portals and high-resolution satellite imagery, and
organized in four thematic layers: population, buildings, service networks,
and land use. The total exposure is given by a weighted linear combination
of the four thematic layers, where weights are calculated using the
Analytic Hierarchy Process (AHP).
The resulting risk map shows the likely damage caused by a lava flow
eruption, allowing rapid visualization of the areas in which there would be
the greatest losses if a flank eruption occurred on Mt. Etna. The highest
hazard levels were obtained within the uninhabited Valle del Bove and along
the upper portions of the South and North-East Rifts. Instead, higher
exposure levels were found near the eastern coast where the population is
highly concentrated and, as a consequence, there are wider urban areas and
critical infrastructures. By combining the location of the main population
centers on Etna with those where the hazard is high, we identified the
south-eastern flank as the sector with the highest overall level of risk
due to effusive eruptions from vents located on the volcano flanks.
FEATURED ARTICLE
Living at the edge of an active volcano: Risk from lava flows on Mt.
Etna
Ciro del Negro and colleagues,
https://pubs.geoscienceworld.org/gsa/gsabulletin/article/doi/10.1130/B35290.1/575769/Living-at-the-edge-of-an-active-volcano-Risk-from
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