NH
Natural Hazards

Volcanic hazard

Stromboli: The Lighthouse of the Mediterranean

Stromboli: The Lighthouse of the Mediterranean

In the last months two paroxysmal explosive eruptions took place at Stromboli volcano: the first one, totally unexpected, on 3rd July (Video 1) that sadly cost the life of a person and the second and, currently, last one about three weeks ago, on the 28th August (Video 2).

Today we try to answer a couple of questions about Stromboli and its eruptions. Are these paroxysmal eruptions common or rare at Stromboli volcano? What are the hazards associated with these eruptions in the context of Stromboli’s island?

The volcanic activity at Stromboli

Stromboli, a volcano located on its homonymous island in the South of the Tyrrhenian Sea, is considered one of the most active volcanoes in the world. Already famous for its persistent explosive character during the Roman ages, they named Stromboli ‘the Lighthouse of the Mediterranean’.

The ordinary eruptive activity of Stromboli is characterised by mild yet spectacular explosions, which eject gas, volcanic ash (i.e. tiny rock particles) and incandescent shreds of magma of decimetric size, i.e. pyroclasts. The latter is particularly capable of putting on a real fireworks display (like in Figure 1), and it is attracting many curious visitors; among them volcanologists, who find Stromboli the perfect natural laboratory where to collect numerous observations.
[Read More]

Let the ash fall, but get ready for its consequences

Let the ash fall, but get ready for its consequences

The past 18th May marked 39 years since one of the most emblematic volcanic eruptions in historic times: the 1980 Mt St Helens explosive eruption. With a death toll of 57 victims, it is the deadliest volcanic event in U.S. history. If that wasn’t enough, it also destroyed hundreds of houses and roads. When we think about explosive volcanic eruptions what commonly comes in our minds about the possible related hazards are impressive Pyroclastic Density Currents (PDC) or Lahars (a glossary below), mainly because of their quick deadly potential, moving ashfall to a secondary role in producing hazards to population.

However, ashfall can be hazardous too even affecting people’s health in the long term and in distal areas from the volcano itself. In today’s post, we will go through how the fall of volcanic ash can be a hazard that must be taken into account by people living in the close (and sometimes not-too-close) neighbourhood of an active volcano. [Read More]

The CRED presents the bill: the socio-economic cost of natural disasters.

The CRED presents the bill: the socio-economic cost of natural disasters.

Which type of natural disaster is the most frequent? And which one causes the largest economic losses? Which populations are mainly affected? What are the necessary steps to reduce natural disasters’ impact? If you have ever wondered about any of these questions, you’d be interested to know that there is an institute answering all of them with a series of reports and ad hoc publications.

We are talking about the Centre for Research on the Epidemiology of Disasters (CRED). The CRED is based, since 1973, at the Université Catholique de Louvain in Belgium and since 1980 it’s a collaborator of the World Health Organization (WHO). Their main goal? Study public health during a mass emergency as well as the structural and socio-economic impact of natural and technological disasters and human conflicts. They maintain the world’s most comprehensive database (EM-DAT) on occurrence and effects of technological and natural disasters from 1900 to the present day: more than 22,000 events and counting. [Read More]

The collapse of Anak Krakatau volcano: a scenario envisaged

The collapse of Anak Krakatau volcano: a scenario envisaged

Krakatoa or Krakatau, in Indonesia, is part of the Ujung Kulon National Park, a UNESCO World Heritage property, and among the most (in)famous volcanoes in the world. From a geological point of view, it is part of the Indonesian island arc system generated by the north-eastward subduction of the Indo-Australian plate (Figure 1). Krakatau is now a caldera type of volcano thanks to the 1883 eruption, one of the most destructive and deadliest volcanic events in historical records causing a total of around 36000 deaths[1, 2, 3]. During this event, up to the 70% of the original island was destroyed, leaving a caldera structure, a ‘bowl-shaped’ depression, leading to a tsunami hitting the coastlines of Java and Sumatra and conspicuous tephra falling over the nearby inhabited islands.

[Read More]