In the shadow of Mount Vesuvius

My first field trip of 2025 was to Naples, for a fascinating day and a half of visits to volcanic sites.?

In Naples, volcanoes are ever present in the public consciousness. From archival paintings dating from the 18th century to decorative art in restaurants and shops, Mount Vesuvius is the most iconic image of modern Naples.?

My Italian colleagues gave me a crash course on managing the city’s disaster risks – most notably the presence of a live volcano. ?I was treated to fascinating insights from volcanologists, seismologists, meteorologists, hydrologists, structural engineers, civil protection officers, psychologists, and risk communicators – including Chiara Cardaci from Italian Civil Protection and Mauro Di Vito, the director of the Italian National Institute of Geophysics and Volcanology (INGV). ?

Our detailed and interesting discussions taught me a lot about volcano risk. ?Here are my highlights:?

1. Every volcano has a unique personality. ?

Not all volcanoes are iconic towering landmarks like Japan’s Mount Fuji, Indonesia’s Mount Merapi, Italy’s Mount Vesuvius, or the Philippines’ Mount Pinatubo. In Naples itself, the Campi Flegrei caldera may not look like it to an untrained visitor, but it is a very active volcanic site. ?? ?

Each volcano has a different style – some are explosive, and others erupt more slowly (“effusive” in volcanologists’ terminology). ?Some have a different character at different times?– sometimes explosive, sometimes effusive. As a result, the hazard potential of every individual active volcano is quite unique. ?

2. Early warning for volcanic eruptions is inherently challenging?

An effective early warning would require that we are able to predict and convey the time, location and nature of eruption at a volcanic site. But this is difficult – especially with sufficient lead time. Probabilistic risk assessments, however, are possible – so we can estimate the likelihood of eruption over 10 years, 50 years and so on. Scenarios can be developed for these likely eruptions. ?

While the science of estimating volcanic risk is seated primarily in the domain of volcanology, it also draws on other disciplines: ?meteorology (to determine which way the wind will carry the volcanic ash), hydrology (to work out how the ground water could be affected), anthropology (to analyze how people may perceive and respond to risk), communication science (to determine the best way to communicate risk). For each scenario, preparedness plans for evacuation and other response measures need to be developed and practised.?

3. Ultimately it is human actions that increase or decrease risk ?

The presence of people, capital assets, and economic activity (e.g. tourism, agriculture) around volcanic sites has steadily increased over the years, sometimes without attention to risk-sensitive land-use planning. ?Some of these areas are experiencing gradual uplift of the ground, a phenomenon known as bradyseism. ? ?

Despite this, human settlements continue to grow – and even flourish – in these areas. This is a major driver of risk. In such areas, we must replan, redevelop and explore adaptive infrastructure that can be modified over time to suit the changing conditions and minimize the risks from seismic events?

4. Historic eruptions can present new risks ?

Signatures of past eruptions are all around volcanic sites, and can become new hazards. ? ?

For example, slopes around volcanic sites have ash deposits from eruptions that may have taken place centuries ago. Extreme rainfall on and around these slopes may cause large and sudden mudslides (lahars) with devastating consequences for nearby human settlements. To manage these risks, we need to adopt a multi-hazard approach.?

5. Volcanoes are resources as well as hazards ?

Volcanic ash from previous eruptions often provides fertile soils for cultivation; many of the rocks around volcanic sites have excellent strength and geotechnical properties that are suitable as construction materials; volcanic sites offer great potential for geothermal energy; and many volcanic sites are picturesque, with fascinating geothermal activity, making them attractive tourist destinations. ?

Because of these features, any human settlement around volcanic sites needs to be carefully managed to maximize the potential benefits and minimize the potential harm.?

The government and people of Italy set an inspiring example in their pursuit of disaster risk reduction. They have made long-term investment in continuous improvements of understanding disaster risk, communicating risk to the population, and co-creating risk management plans with all stakeholders.?