The geological processes which dictate volcanic activity go largely unnoticed in every-day life, and it’s only when they erupt do they demonstrate the true power of the Earth. Suffice to say historical accounts, and those who have witnessed such events, help us to not take it for granted and prepare for eruptions to come. Here are 5 of the most impressive volcanoes:
Where better to start than the land of ice and fire? Iceland is home to 30 active volcanic systems and over 130 volcanoes, some of which are predicted to erupt very soon but, despite the potential danger, it is their very presence that could lead Iceland to pioneer a new type of renewable energy.
By Batintherain at English Wikipedia (Transferred from en.wikipedia to Commons.) [Public domain], via Wikimedia Commons
Already bastions of geothermal energy, studies are currently underway as to whether magma pockets near the surface could be tapped for energy upon discovering a magma chamber 2.1km under Iceland’s Krafla volcano. Scientists from the Krafla Magma Testbed Project are seeking to set up the world’s first magma observatory and are looking into the application of volcano energy around the world.
25 institutions are working together to harness this new kind of energy which uses supercritical heat, and could potentially be used to control eruptions. Once the technology is developed the supercritical heat from volcano energy has could produce between 5 and 10 times more energy than regular geothermal, and can be utilised by any country with volcanic activity providing a much needed source of renewable energy.
Nishinoshima Island, Japan
Geology dictates volcanology, which in turn dictates topography. This archaic association is usually played out slowly over millennia making it difficult to visualise over one lifetime, however volcanic eruption gives us this chance by speeding up the process.
Dramatic changes can come about from eruptions, including the creation of entire islands. This was the case for Nishinoshima Island, whose eruption in 2013 birthed a new island 25m above sea level in just under a month.
Flickr | Stuart Rankin
This happened through two types of eruption; the first being what’s known as Surtseyan eruption, the release of boiling lava into cold seawater forming steam and driving molten material upward; and the second, a Strombolian eruption, cascading lava flows from the peak of the island above sea level which build-up and cool down, adding form to the island.
Nishinoshima has remained active since the 2013 and soon after the new island’s creation the two islands became one again. Nishinoshima continues to spew lava creating new land.
The Yellowstone Caldera, USA
Yellowstone National Park has long been considered a dream destination for seismologists and geologists alike as it boasts activity such as tremors, geysers and vibrantly coloured hot springs, including the Grand Prismatic. This concentration of activity is the result of the underground processes of one of the largest volcanoes on Earth.
By David L. Sifry (David L. Sifry) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
One of 20 known supervolcanoes the Yellowstone Caldera has enough magma underneath it to fill the Grand Canyon 11.2 times. Calderas are formed when the outer walls of a volcano mouth collapse in on a rapidly emptied magma chamber, creating a shallow crater.
On average supereruptions occur once every 100,000 years, but by no means should we put them at the back of our minds. Supereruptions are not to be underestimated as just one is the definition of cataclysm; the last time Yellowstone erupted was around 640,000 years ago sending 1000 cubic km of volcanic material into the air, enough to bury a city under a few kilometres of ash.
If Yellowstone were to erupt today it would kill thousands, cause economic instability and potentially trigger a volcanic winter; a global temperature drop caused by ash and sulphuric acid flung high into the atmosphere, blocking out the sun and increasing the reflection of solar heat (otherwise known as the albedo effect).
Kroatoa is a low-lying volcanic island located off the coast of Indonesia and its eruption in 1882 triggered a volcanic winter. The eruption unfolded over the course of two days in August through four distinct explosions. The shockwaves from these were recorded worldwide and the loudest was heard in Australia some 3000 miles away. The island sank upon each eruption causing four subsequent 120ft tall tsunamis.
By flydime [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
The volcanic ejecta consisted of a 275 mile wide ash cloud, completely obscuring the sun in the immediate area. In fact there was so much ash that it changed the colour of the sky at sunset around the world for 3 years; a striking range of blood red tones known as Krakatoa twilights. This ash was also responsible for a global temperature decrease of 1.2°C (eventually righting itself in 1888).
The 1883 eruption was said to have blown 2 thirds of the island away. Since then Kroatoa’s original caldera has raised up through a process called resurgence; a build-up of pressure from the magma chamber causing a new peak to rise. This new volcanic peak is referred to as Anak Krakatoa, translating to “Child of Krakatoa” and has one of the lowest elevations in the world of 813m.
Mount Nyirangogo, Democratic Republic of Congo
Volcanoes aren’t all bad though. The previously mentioned associations influencing the land place geology at the heart of ecology. DCR’s Virunga National Park, the first designated national park in Africa, is home to two of the most active volcanoes on Earth, one of which being Mount Nyirangogo. Though catastrophic in their creation, well established volcanoes become verdant over a longer time frame.
MONUSCO/Neil Wetmore [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
Volcanoes become biological wonders by creating shifts in elevation, climate and substrate as well as ejecting nutritive volcanic minerals to enrich the soil. In fact a correlation can be seen between the most volcanically active areas on Earth and those with the highest biodiversity.
The volcanic nature of the park is part of the reason Virunga holds half of the biodiversity found in all of Sub-Saharan Africa.