5. Mount Fuji – Honshu, Japan
Little more than 95 miles from Tokyo stands the iconic Mount Fuji – a volcano that, the Japan Meteorological Agency warns, is under threat of erupting. Worryingly, as maintained by a July 2014 paper researched by experts in Japan and France, the peak is also “under great pressure” following 2011’s devastating magnitude-nine Tohoku earthquake. Dr. Florent Brenguier, the paper’s principal writer, claimed that while “it is not possible” to predict the timing or scale of an eruption using the findings, he is expecting “a new earthquake” in the volcano’s vicinity – something that would further increase the risk of Fuji blowing its top. Indeed, Fuji’s last explosion in 1707 followed an 8.7-magnitude quake.
That most recent eruption saw nearby municipalities bombarded by burning cinders and the location of modern-day Tokyo enveloped in nearly two inches of ash. Today, a comparable level of destruction would cost more than $30 billion to rectify, while three-quarters of a million people would be driven from their homes. Meanwhile, still bigger potential eruptions could grind Tokyo’s economy to a dead stop and jeopardize road and rail connections to the heart and western part of Japan, paralyzing the country’s manufacturing industry.
4. Katla – Iceland
Back in 2010, gigantic volumes of ash from southern Iceland’s exploding Eyjafjallajökull volcano closed swathes of European airspace. However, just over 17 miles from its crater is another, far more menacing volcano: Katla. In fact, the potential power of this threat is such that the Eyjafallajökull experience may only be a tenth as damaging as Katla’s next eruption. And according to University of Iceland geophysicist Páll Einarsson, history dictates that when Eyjafjallajökull blows, Katla is unlikely to be far behind. In fact, Katla generally rouses approximately every 80 years, and its last blowout was in 1918.