Our Beautiful Planet: Nature after volcano eruptions
Melanie Hall
May 18, 2018
Their destructive power sweeps away everything in their path – but what volcano eruptions leave behind is a fertile environment that bursts forth with life.
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When you think of a volcano eruption, destruction and devastation, recently witnessed in Hawaii, spring to mind. Although their catastrophic power isn't doubted, the positive ecological benefits of the aftermath, and nature’s ability to return, shouldn't be underestimated either.
A large variety of animals and plants, killed by the lava and the ensuing volcanic ash, can quickly return to the volcano area and rebuild the ecosystem, even after a huge eruption.
Lava can be a rich source of nutrients, including iron, potassium and sodium, so soil consisting of volcanic rocks and ash is extremely fertile, boosting vegetation growth. It also makes for prime agricultural land.
One of the first ways life returns to areas destroyed by a volcano eruption is often through small plants like mosses, which help break down rock into soil for other plants grow in.
Mount St. Helen's, in the state of Washington, is the deadliest and most economically-destructive volcanic eruption in US history to date – and is a good example of nature's incredible ability to bounce back following disaster.
Its eruption in 1980, triggered by a 5.2-magnitude earthquake, buried the 200-feet-deep Spirit Lake under layers of ash and mud within hours of it blowing its top. So much water was displaced by the avalanche that hit the lake that huge waves washed over the mountainside.
Although the old lake was gone, a new lake started to take shape as runoff drained into the same place. The new, wider and shallower lake is rich in aquatic life – with signs of life emerging as soon as within a year. It has also benefited from the lack of huge trees that used to block out the sun, leading to more insects and bigger fish including rainbow trout.
As for the vast expanse of forest which was destroyed, life there, too, has returned – in some ways even richer than before. The eruption had devastated the area's wildlife – not a single tree was left standing within a 6-mile radius of the summit. An estimated 7,000 big game animals were killed.
But in the first weeks after the disaster, life was already returning. Charlie Crisafulli, an ecologist with the U.S. Forest Service Pacific Northwest Research Station, has previously said how he saw ants on the ground and pocket gophers digging through the ash in search of food, while fallen trees became homes for insects and gave nutrients back to the soil.
The new landscape gave rise to a whole new ecosystem, with huge swathes of land once dominated by tall trees now exposed to sunlight. This meant a range of plants, insects, small mammals and birds could move in.
The conifer forest, meanwhile, was replaced by deciduous woodland. The new burst in plant growth also encouraged the arrival of elk, which increased to record numbers.
The explosion in nature around Mount St. Helen’s, more diverse than before the eruption, is testament to how tenacious life can be.
Fire-spewing mountains
Four years since the volcano Eyjafjallajökull erupted and disrupted European air traffic for days, the earth in Iceland is rumbling anew. But what's is actually happening deep beneath the surface?
Image: picture-alliance/dpa
Volcano rumbles under glacier
The highest warning level, red, has been declared for the Bardarbunga volcano in Iceland. The volcano is nearly invisible, hidden well beneath the Vatnajokull glacier. The weather office says nearly 2,500 earthquakes have been registered in the last few days. Signs of magma movement have also been detected.
Image: Reuters
Remembering Eyjafjallajökull
Four years ago, the eruption of Icelandic volcano Eyjafjallajökull disrupted European air traffic for six days. More than 10 million air travelers were affected, and the disruption resulted in $1.7 billion ( 1.3 billion euros) in lost business. Bardarbunga is even larger than Eyjafjallajökull and would release much more magma during an eruption.
Image: AP
Natural phenomenon or catastrophe?
Worldwide there are at least 500 to 600 active volcanoes. Every year about 50 of them erupt. Volcanic eruptions are fascinating as natural phenomena, but when humans are endangered, things can quickly turn catastrophic. Huge lava streams and pyroclastic flows can engulf entire villages without warning.
Image: picture-alliance/Sebastian Widmann
From scorching lava to lush green
Shorty after such a violent explosion, however, life returns. First, plants regrow and people return to rebuild their destroyed towns at the foot of the volcano. They do so despite the danger, because they know that volcanic ash makes for very fertile soil and thus good harvests. It is rich in phosphorus, potassium and calcium.
Image: Fotolia/Daniel Strauch
The most volcanic island on earth
With an area of around 103,000 square kilometers (40,000 square miles) and about 30 active volcanoes, Iceland is considered the largest volcanic island in the world. Eyjafjallajökull in April 2010 and Grímsvötn in May 2011 are two of the most famous eruptions. The record-breaking volcanoes are, however, not in Iceland.
Image: picture-alliance/dpa
The most active volcano
Kilauea in Hawaii is the most active volcano on earth. It releases the most magma but is normally not explosive. The name of the volcano in the Hawaiian language therefore means "spitting" or "lots of spreading." Lava isn't released explosively, but springs forth from the earth's interior and is released in lavaflows. On January 3, 1983, an eruption began that has persisted until this day.
Image: picture alliance/dpa
The largest volcano
The largest volcano is also found in Hawaii: Mauna Loa. It is 4169 meters tall (13,700 feet), and, when measured from sea level, it is one of the tallest mountains in the world. Measured from the ocean floor, its actual height is about 10,000 meters (32,800 feet). Mauna Loa last erupted on March 25, 1984 and is currently dormant.