Geology

Iceland sits astride the middle of the Mid-Atlantic Ridge, which is an integral part of the global mid-oceanic ridge system. This ridge is a 10,000-mile crack in the ocean floor caused by the separation of the North American and Eurasian tectonic plates. The Mid-Atlantic Ridge has made Iceland into a landmass between the submarine Reykjanes Ridge to the southwest and the Kolbeinsey Ridge to the north, and has been active during the last 20-25 million years, broadly coinciding with the time-span of active volcanism in Iceland.

Accordingly, the western part of Iceland, to the west of the volcanic zones, belongs to the North American plate and the eastern part to the Eurasian plate. Where plates meet, they can rub against each other as they slide in opposite directions; they can collide head-on in a stalemate, pushing each other up or down like two fighting rams; or one might win out and push the other one beneath it. Sometimes, they only move away from each other, releasing pressure and exposing the lava sea between them. This allows the lava to stream to the surface, where it cools down and forms new land. When this happens, the area of separation is called a "constructive junction," and this is precisely what is happening in Iceland.

Eruptions and Earthquakes

Volcanic eruptions and earthquakes follow each other. Parts of Iceland are
frequently shaken by earth tremors. Catastrophic earthquakes occur at longer
intervals than the volcanic eruptions. Some of the worst earthquakes
devastated large areas of southern Iceland in 1784 and 1896. The last
tremors were in 2000 and 2008, causing some structural damage to buildings
but no casualties or serious injuries.

Volcanic Eruption

There are over a hundred volcanos on the central plateau which have not
erupted in the past thousand years and between 30 and 40 that areactive,
meaning that they have erupted within last few centuries. On average,
Iceland experiences a major volcanic event once every 5 years. Since the
Middle Ages, a third of all the lava that has covered the earth's surface
has erupted in Iceland. However, according to a recent geological
hypothesis, this estimate does not include submarine eruptions, which are
much more extensive than those on the land surface.

The most famous and active volcano in Iceland is mount Hekla, which has
erupted 18 times since 1104, the last time in 2000. The eruption caused no
damages, injuries, or casualties. Other active volcanos, measured in terms
of the number of eruptions besides Hekla, are Grímsvötn, Katla, Askja and
Krafla. Katla, has erupted about 20 times since the settlement of Iceland.

Heimaey

A volcano in Heimaey in the Vestmannaeyjar Islands off the south coast,
which was thought to be long extinct as it had not been active for about
5,000 years, suddenly erupted in 1973. Heimaey is the largest of the
Vestmanneyjar Islands, and the only one that is inhabited. The fishing town
of Heimaey, with a population of 5,300, was only 200-300 m away from the
eruption, which began without warning in the volcano Eldfell during the
night of 23 January in 1973.  Nearly all the inhabitants were evacuated to
the mainland by fishing boats and aircraft during the first night, and no
one was injured. Only a few hundred people stayed behind to carry out
necessary work. The eruption lasted 5 months and the village was nearly
destroyed by lava, ash and fire. Miraculously, two-thirds of Heimaey was
saved by using barriers and huge jets of water to cool the lava, which in
turn created a rock damn against the flow. Ironically, by the time the
eruption was over, the town's harbour was even better than before - the new
land provided greater protection from wind and water. After the end of the
eruption, people started to move back and the population is now about
4,900. The
Vestmannaeyjar islands are now a popular tourist location. Promoted as the
Pompei of the North, it is a must-see for geo-tourists!

Surtsey

A typical submarine eruption occurred on the Reykjanes Ridge in 1963,
resulting in a new island, Surtsey, which forms part of the same archipelago
as Heimaey. It emerged from a depth of 130 m during an eruption which lasted
until 1967. At its largest, this new island had an area of 2.8 km², but has
now been reduced by wave action to 1,5 km².

Lakagigar

At numerous times in Iceland's history, volcanos have meant disaster. The
largest recorded lava flow in world history occurred here in the summer of
1783, when a 25-km crater row, Lakagigar, southwest of Vatnajökull, poured
out 3 cubic miles of lava, the greatest lava flow witnessed on Earth, at
least in the last millennium. So much ash was released that the sun was
obscured for a time, and hundreds of thousands of sheep and cattle perished
from the poisonous gases. The ensuing famine led to the death of 20% of the
population, or about 10,000 people. The lava-field created by the eruption
covered 580 km², with a total volume of 12 km³. During the summer of 1783, a
bluish haze from the eruption covered Europe and Western Asia, causing
difficulties in agriculture there.

Volcanos and Energy

 The same geological activity that creates the volcanos provides an endless
supply of geothermal energy. Over 90% of housing in Iceland is heated by
natural geothermal heat - one of the cheapest and cleanest forms of energy
in existence. Hot springs can be found almost everywhere, and the melt water
created by sub-glacial volcanos provides the country with a huge potential
source of of hydroelectric power. All this clean energy has made Iceland the
least polluted country on Earth.

According to researchers at Yale and Columbia universities, Iceland ranks
first out of 163 countries on their Environmental Performance Index, as
reported by Forbes magazine on April 21, 2010. Researchers ranked countries
based on 25 indicators, including water and air quality, greenhouse gas
emissions and the impact of the environment on the health of the population.