Mount Fuji is not only a national symbol for Japan, but also an active volcano that last erupted in 1707

Mount Fuji In ‘Critical State’: Eruption Possible?

Japan’s iconic Mount Fuji is in a “critical state,” according to researchers, leading to fears that an eruption may be imminent.

The highest point on the Japanese archipelago and a national symbol, Mount Fuji is constantly monitored by the government, due to its nature as an active volcano. Fujisan, as the Japanese call it, has rarely stirred in modern times, but researchers claim that the Tohoku earthquake of 2011 has increased subterranean pressure below the mountain, which sits at the meeting point of three tectonic plates.

Researchers used a novel technique, according to a report in The Guardian, to echo-scan the bowels of the Earth under Mount Fuji. With 800 sensors, Japan’s seismic network is one of the densest in the world, and by focusing on signals commonly known as “seismic noise,” which are the result of constant interaction between ocean swell and solid earth, scientists were able to map geological disturbances caused by the earthquake’s seismic waves.

According to Florent Brenguier, a researcher at the Institute of Earth Sciences and the lead author of a study on the findings, “Seismic waves travel a very long way, going round the world several times. Their movement makes the Earth’s crust vibrate, and rather like a shock wave this produces breaks or cracks in the rock.” As io9 relates, Brenguier’s team discovered that the greatest disturbances were centered in the bedrock under Mount Fuji. The volcanic regions “are the ones where the fluids trapped in the rock – boiling water, gas, liquid magma, which cause an eruption when they rise to the surface – exert the greatest pressure,” according to Brenguier, who pointed out that “the seismic waves add to this pressure, causing even more disturbance.”

While the pressure under Mount Fuji is building, Brenguier posits that scientists have no way of knowing when, or even if, and eruption could take place:

“We cannot establish a direct relation of cause and effect between quakes and volcanic eruptions, even if statistically the former lead to an increase in the latter. All we can say is that Mount Fuji is now in a state of pressure, which means it displays a high potential for eruption. The risk is clearly higher.”

Recently, The Inquisitr has reported on heightened fears that a dormant super-volcano under Yellowstone Park in the United States may be showing signs of life, as evidenced by increased thermal activity in the region. While the two events are not thought to be connected, the techniques developed by Brenguier and his team could be used to examine other areas of seismic and volcanic interest, such as Yellowstone.

Mount Fuji last erupted in 1707, an event preceded by a magnitude 8.7 quake to the south of Japan, 49 days earlier, that generated a tsunami which claimed 5,000 lives. While the Tohoku earthquake and its attendant tidal wave are three years in the past, researchers caution that elapsed time does not necessarily mean Mount Fuji is slumbering.

[Image via TNW]

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