Curious news - Mt. Fuji showing signs of life
From
Volcano Discovery:
Mt Fuji Volcano (Japan): increase of pressure in the magma chamber as a sign of an impending eruption
Scientists have discovered signs of a possible imminent eruption of Japan's most famous volcano, Mount Fuji on Honshu. At least this is what many headlines in the press read.
According to an article of the Japanese news agency Kyodo the pressure in the magma chamber beneath the volcano Mt Fuji has drastically increased after the tsunami in March 2011 and a magnitude 6.4 quake near the volcano four days later, and is currently higher than it was before the last eruption in 1707 some 300 years ago.
Scientists at the National Research Institute for Earth Science and Disaster Prevention have calculated that the tectonic shifts in the past year caused an increase in pressure to 1.6 megapascals. That is sixteen times as much as the threshold of 0.1 megapascals needed for an eruption, they said.
Such statements should be viewed with caution, because the figures are obtained by indirect calculations, which may be subject to very large errors. Secondly, pressure data for magma chambers inside a volcano without an associated depth profile have little significance. Pressure inside a volcano, as everywhere, increases naturally with depth. What matters is the difference between the lithostatic pressure (weight of the volcanic edifice) and the gas pressure of the gases in the magma. If this difference becomes greater than the tensile strength of the rock, it can open cracks and let the magma erupt.
I don't know how built-up the area is surrounding Fuji -- considering its most recent eruption was 1708, the collective consciousness of the people nearby might have forgotten that their neighbor is very very active. Judging from
these images it seems to still be very rural.
Posted by DaveH at September 10, 2012 6:55 PM