Lloyd Busch is the author of "Passive Resistance", a book on non-violent action, and has been published in the "Journal of Theoretics".
Katla Volcano: An Earth-Altering Eruption
Katla is perhaps the most dangerous volcano in Iceland. It produces large eruptions every 50 to 100 years with an average of 80 years between eruptions. The last major eruption to break through the glacial ice cap was in 1918; the ash plume reached 14km into the atmosphere and the eruption lasted for 24 days.
The 9-mile wide caldera of the volcano is located deep underneath a glacier. When an eruption occurs, all of that ice will rapidly melt, creating a Jökulhlaup, the Icelandic term for a glacial outburst flood. These outbursts create deadly lahars (torrents of mud and volcanic ash). Lahars extended the southern Icelandic coastline by 5 km during the 1918 eruption.
NASA's Earth Observatory has documented dramatic reductions in the ice cap over Katla in recent years as a result of an increase in smaller volcanic episodes and geothermal heat. In recent years hundreds of micro-earthquakes have been detected around the area of the caldera. Most of us still remember the infamous eruption of Eyjafjallajökull in 2010 that created the transportation nightmare throughout Europe. Well, several previous eruptions of Eyjafjallajökull were followed by eruptions at Katla, though the link between the two volcanoes is not understood.
The 1918 eruption of Katla produced five times as much ash as Eyjafjallajökull did in 2010. An eruption of Katla in 934 A.D. had a Volcanic Intensity Index (VEI) of 6, producing some 5 cubic km of tephra, or ejected material, and 18 cubic km of lava. The combination of flash floods, lahars, and ash would prove deadly for the people of Iceland; the eruption would destroy and poison large areas of agriculture within Iceland.
While the inevitable eruption of Katla would prove disastrous for Iceland, its potential effects could be felt globally, and not just from transportation disruption. The coming eruption has the potential to create a global cooling effect on Earth's climate called a volcanic winter. While this might seem like a good thing, considering global warming, the cooling would far outpace recent warming trends. The eruption in 1783-1784 from the fissures of Laki, part of the same volcanic system as Katla, cooled the temperatures in the northern hemisphere by 3º C. When the next eruption occurs at Katla, the enormous amount of ash produced would likely cause a similar cooling effect on Earth's climate, potentially leading to famines that could kill hundreds of thousands of people worldwide.
1918 Eruption of Mount Katla
Mount Fuji: 300 Years Overdue
Japan's Mt. Fuji is perhaps one of the most recognized volcanoes in the world; its utter beauty and symmetry have made it a popular tourist destination for over 200,000 people every year. Yet beneath this beauty lies a sleeping giant whose fury only grows the longer it slumbers.
The last eruption of Mt. Fuji was in 1707 and sent ash as far away as Tokyo and up to 280 km over the Pacific Ocean. During this eruption, ash rained down on Tokyo for two straight weeks. The eruption was preceded by an 8.4 earthquake which devastated Honshu Island. Recent research has concluded that the eruption of 1707 was likely triggered by the earthquake that preceded it.
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According to one of Japan's leading volcano experts, Shigeo Aramaki, in the last 2,200 years Fuji has erupted 75 times, giving an average 30-year interval between eruptions. Mt. Fuji has now been silent for over 300 years, ten times the average lull between eruptions. Hiromu Okada of Hokkaido University, who helped predict the eruption of Mount Usu, states that “If some magmatic system is ready or nearly due to erupt, an earthquake could be an effective trigger”.
The entire Japanese archipelago is a very active earthquake zone as it sits on the convergence of four separate tectonic plates including the infamous Ring of Fire. With Mt Fuji constantly building pressure, all it could take to send it over the edge is a powerful earthquake. It is estimated that an eruption would cause $21 billion in damages. The potential for heavy loss of life is extremely worrisome as Tokyo with its population of over 37 million people sits directly in Mt. Fuji's cross-hairs.
In recent years there has been an increase in smaller earthquakes at Mt. Fuji which could indicate the movement of magma underground inside the volcanic system. This could be a sign that the volcano is preparing for another eruption. Mathematical models indicate that the pressure inside Mount Fuji's magma chamber may be greater now than it was before the eruption in 1707.
An interesting note is that Mount Fuji is the point where three separate tectonic plates converge: the Amurian Plate, the Okhotsk Plate, and the Filipino Plate. It just so happens that not only is Japan overdue for an eruption at Mount Fuji, but it is also overdue for a major mega-thrust earthquake along the Nankai Trough. This fault is expected to rupture sometime in the near future, producing an earthquake of 9.0 or larger, more than enough to trigger nearby Mt. Fuji. Such a sequence would create a perfect storm of apocalypse for the people in the area: a major mega-thrust 9.0 earthquake, a resulting mega-tsunami which would strike the area before evacuations could begin, and then a major eruption at Mt. Fuji that would hamper any recovery operations. Dark times are indeed ahead.
Iceland's Volcanic System
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© 2016 Lloyd Busch
Comments & Thoughts
Joseph Ritrovato from Vancouver, WA (nextdoor to Portland, OR) on March 22, 2017:
Excellent hub! I just want to mention a few things related to Fuji's last eruption. The earthquake that preceded it on 28 or 29 October 1707, was considered the largest in Japan's historical record until the 11 March 2011 earthquake occurred. That earlier quake, although not as large (estimated to have been 8.6-8.7 in magnitude), was much closer to Fuji than the more recent 9.0 magnitude seismic event. Not only is Fuji long over-due for an eruption, but a repeat of the 1707 earthquake could occur at any time as well. However, more likely would be two separate ruptures, occurring within days (such as happened on 23 & 24 December 1854; which produced two 8.4 magnitude quakes) or in years (such as happened in December of 1944 and 1946; resulting in two 8.1-8.3 magnitude events).