Most Dangerous Volcanoes

To most people, a dangerous volcano is the one that’s currently on the news or has just erupted nearby; however, insurance risk experts and scientists use objective criteria to identify the worst threats, even if the volcano might not be erupting just now.

♦ Getting insurance under the volcano

Most people have a pretty good general idea what a volcano can do.  Burning hot lava comes out of it during an eruption, and ash and mud flows may pour down its sides. There are also earthquakes, and sometimes a volcano will even explode as Mount St. Helens did in May of 1980.

The precise science of it gets complicated, but so do the lives of the people nearby during and after the eruption. Insurance helps both individuals and businesses get going again, but property insurers have sometimes withdrawn all policy coverage for volcanic eruptions after a particularly bad one has cost the entire industry a large sum.

That hurts everybody, including the insurance industry, according to the Willis Research Network, one of the top global partnerships between science and insurers. In an April 2010 paper on volcanic risk (link is to a PDF file), they note that this is especially true at tourist destinations around many European volcanoes, where lack of property insurance can affect sales of motor vehicle, aviation, farming, and health insurance.

Rather than completely withdraw from the market, the Willis group asks, why not take into account the duration and variety of impacts that happen during a volcanic disaster and extend the length of the currently 72-hour-long clause covering damage from natural disasters. While it might cost the industry more in high-risk areas, more policies will be sold everywhere, including areas where volcanoes are unlikely to erupt any time soon. It is potentially a win-win situation.

♦ The 10 most dangerous volcanoes in Europe

In identifying high-risk volcanoes for their report, the Willis researchers came up with an assessment system based on how a volcano generally erupts – some, like Piton de la Fournaise, will most often have non-explosive, effusive eruptions. The group also included the most likely hazards from the volcano, such as lava flow, tephra (described by the U.S. Geological Survey in an online PDF children’s outreach brochure as “fragments of volcanic rock and lava of all sizes that are blasted into the atmosphere by explosions or carried upward in eruption columns or lava fountains”), earthquakes, pyroclastic flows, dangerous gases, mud flows, and tsunamis. Finally, they ranked the volcano’s danger according to wind and population data, as well as residential property value at risk.

The top 10 high-risk volcanoes in Europe and its overseas territories, according to the Willis Research Network, are (from 1 to 10):  Vesuvius (Italy), Campi Flegrei or Phlegraean Fields (Italy), Soufriere (Guadaloupe), Etna (Sicily), Agua de Pau (Azores), Soufriere (St. Vincent), Furnace (probably France’s Piton de la Fournaise on Réunion Island), Sete Cidades (Azores), Hekla (Iceland), Mount Pelee (Martinique), Soufriere Hills (Montserrat), Vulcano (Italy), Stromboli (Italy), Tenerife or Teide (Canary Islands), and Katla (Iceland).

In sum, if the research group’s proposal is adopted in some form, most of those living near one of these European volcanoes may be able to get insurance, but it’s going to be expensive

♦ An early warning system for U.S. volcanoes

In June 2005, the U. S. Geological Survey released a report on 169 volcanoes in the United States and called for the formation of a national Volcano Watch Office as part of an early warning system to monitor dangerous U.S. volcanoes around the clock for signs of an impending eruption.

Since 12 of the 16 biggest eruptions over the past 2 centuries have happened at volcanoes that hadn’t had an eruption in recorded history, according to British vulcanologist William McGuire, this is a proposal worth considering.

An estimated half of the country’s most dangerous volcanoes already have at least basic monitoring ongoing now, the Geological Survey says, and a few of these are monitored very closely. There are five volcano observatories in its Volcano Hazards program, one each for volcanoes in Hawaii, the Cascades, Alaska, Long Valley in California and at Yellowstone National Park. As well, the program keeps an eye on volcanoes in the Northern Marianas, which are directly in the path of very heavily traveled air routes.

♦ Very-high-threat volcanoes in the U.S.

The U.S. Geological Survey undertook its volcanic threat assessment (link is to PDF file) by evaluating factors common to all volcanoes, including hazard and exposed population.

Examples of the hazards they are concerned about include the type of volcano, whether there are seismographic or other signs of unrest happening, the general frequency of past eruptions as found by studying local rocks, and the volcano’s tendency to erupt explosively. When studying population exposure, the Survey looked at such things as permanent and transient local population, power generation/transmission and transportation infrastructures and the presence of air traffic through the area.

The result was the identification of these volcanoes as the ones that present the highest threat: in Alaska (where the Alaska Volcano Observatory has webcams pointed at some of the most beautiful mountains in the world), Akutan, Augustine, Makushin, Redoubt, and Spurr; in California, Lassen, Long Valley Caldera, and Shasta; in Oregon, Crater Lake, Hood, Newberry, and South Sister; and in the State of Washington, Baker, Glacier Peak, Rainier, and St. Helens (which was erupting when the report was released).

Here is an illustration of how the factoring systems work. The scientists put Yellowstone volcano in the high-threat category, below Long Valley Caldera, although both are the same sort of “super-volcano” type of system. Per the U.S. Geological Survey report, “The large Long Valley caldera system, which has exhibited recurring signs of unrest for more than two decades and is close to major resort development and transportation infrastructure, also falls in the very-high-threat group.”

Rainier, Vesuvius, Etna, and Tenerife/Teide are also on the Decade Volcanoes list of 16 hazardous volcanoes throughout the world that also serve as good research sites.

Volcanoes may be listed in many different ways. What is always needed is the ability to recognize factors that all volcanoes have in common and then to sort them according to some established human priority. Geologists and insurance risk researchers have each developed useful sets of criteria to identify the most dangerous volcanoes in Europe and the United States far enough in advance so that we can, hopefully, prepare ourselves sufficiently for the next big eruption, wherever and whenever it may occur.