Last month, ash plumes emitted by the Eyjafjallajökull volcano in Iceland at one point forced the closing of airports in 28 countries, and has resulted in over $17 billion in economic losses -- considerably exceeding the costs for grounding carriers immediately after the 9/11 terrorist attacks on the U.S.
The chaos wreaked by the Iceland volcano serves as a reminder to scientists that Japan's largest volcano, Mt Fuji, is by no means extinct. And at 3,776 meters in height, Fuji is not only considerably bigger than the 1,666-meter Eyjafjallajökull, but is also located relatively close to major population centers.
Writing in Shukan Toyo Keizai (May 15), earth science professor Hiroki Kamata of Kyoto University supposes if Fuji were to erupt of the same scale as its last recorded eruption in 1707, the destruction would be far greater this time.
The 1707 eruption, from craters on the east-northeast flank of the mountain, released an estimated 800 million cubic liters of ash, which accumulated to a depth of 10 cm in Yokohama and 5 cm in Edo (present-day Tokyo). So thick was the ash that the skies darkened at midday.
People in 1707 did not have to worry about computers, whose power supply and air vents may be especially vulnerable to fine dust particles. A modern-day eruption could very likely wreak havoc with the nation's business and communications.
Airborne ash particles would also clog the air filters of cars and trucks, causing vehicle traffic to grind to a halt. For those that keep running, driver visibility would likely be affected. Using windshield wipers to clear airborne grit would cause permanent scratches to be gouged into the glass. And after a rain, the water and ash mixture might make roads so dangerously slick that the Tomei and other expressways would have to shut down until the paving could be swept clean.
Needless to say, should the ash travel eastward, flights to and from both Haneda and Narita airports would be grounded for the duration.
Likewise, the toll on human health would be immense: respiratory complaints such as asthma and bronchitis would almost certainly soar, along with eye irritation.
In June 2004, Japan's cabinet office made public a hypothetical calculation for the economic impact based on a Mt Fuji eruption of the same scale as the one in 1707. The damage projections reached 2.7 trillion yen.
But how worried should we be? Professor Kamata notes that current magma activity under Mt Fuji is low and no precursors foreshadowing an eruption are evident. However, once an eruption were to begin, Tokyo and environs would be paralyzed for several months.
Volcanos are the Godzillas of the global environment. Kamata notes that eruption in Iceland in 1783 killed three-fourths of that nation's livestock population due to lack of feed, and one-quarter of the country's human population expired from starvation. Sulfur emissions combined with water created a "blue haze" that blocked sunlight, causing Europe's average temperatures to drop by 1 degree Celsius for the next decade.
The 1991 eruption of Mt Pinatubo in the Philippines had a similar, albeit smaller, impact on climate in the region.
At least modern-day volcanologists have developed methods for detecting when eruption is imminent, such as by gauging the depth of tremors beneath the mountain and using devices that measure outward swelling on the slopes. The Meteorological Agency is then alerted and warnings issued, hopefully minimizing the extent of damage. Waiting until volcanic ash fills the skies, warns Kamata, is already too late.
No one knows when Mt Fuji will erupt again, but unlike earthquakes, it will give out clear warnings well beforehand. Harnessing the latest technology and adopting proactive measures is an absolute "must" for future disaster management.© Japan Today