Volcanoes

Volcanoes are the plumbing system of the Earth and are an ever present danger. Currently, most thinking is around the threat of a massive volcanic eruption, However, a team of experts now argues that too much focus is on the risks of these rare volcanic explosions, while far too little attention is paid to the potential domino effects of moderate eruptions in key parts of the planet.

Researchers at the University of Cambridge’s Centre for the Study of Existential Risk (CSER) have identified seven “pinch points” where clusters of relatively small but active volcanoes sit next to vital infrastructure that, if paralyzed, could have catastrophic global consequences.

A team of geologists and geophysicists, led by the University of Geneva, Switzerland, has studied what causes a volcano to erupt and why some erupt regularly, while others remain dormant for thousands of years. They determined that most of the magma rising from depth actually does not cause a volcanic eruption.

Magma is molten rock that rises from tens of kilometers deep to the Earth’s surface. “During its journey, magma can get trapped in reservoirs within the Earth’s crust, where it may stagnate for thousands of years and potentially never erupt,” says Meredith Townsend, a researcher at the Department of Earth Sciences of the University of Oregon.

The nature and growth of magmatic plumbing systems are very important to geology. Traditionally, magma chambers have been viewed as bodies of molten rock or partially crystallized ‘magma mush’ connected to the surface by a narrow cylindrical conduit. 

Recent data suggest, however, that magma chambers beneath volcanoes are formed gradually through the union of smaller conduits. 

Although they don’t occur very frequently, the threat of a supervolcano eruption is ever present. Supervolcanoes are defined as a volcano that has at least one explosion of magnitude 8. This is the highest ranking of the Volcanic Explosivity Index, or VEI, meaning it has released more than 1000 cubic kilometers of material.

When these huge volcanic eruptions explode, the associated super eruption represents the most catastrophic of events caused by a natural hazard, resulting in widespread ash-fall blankets and pyroclastic flows, which can be hundreds of meters thick, covering thousands to tens of thousands of square kilometers.