southern and Snaefellsnes volcanic areas are clear examples of the so-called
Katla is one of the
largest calderas of the country, 700 metres deep and 110 kilometres
square. It is situated at the southern end of the Eldgja volcanic
system. During eruptions,
tephra mixed with water has three escape routes from the volcanic areas,
through the so-called Entugja gorge down to the outwash plain
Markarfljotsaurar, under the Solheimajokull glacier tongue as well as
down the Myrdalís sander outwash plain.
Katla has only produced lahar floods, up to 1 km≥ in volume.
The magma chamber under the volcano is estimated to be at the
depth of 1-1Ĺ kilometres. Its highest part therefore might lie above sea level, which
makes it the shallowest one in the country.
It contains 30-40 km≥ of magma.
main structure of the archipelago is alkaline rock, similar to the
structure of the Snaefellsnes peninsula.
After the Surtsey eruption 1963-1967, and the Heimaey eruption in
1973, scientists have come to the conclusion, that igneous rock weathers
the southwestern lowlands is a so-called Transform Fault, which is about
80 km long and 10 km wide.
The northern edge of the fault moves west and the southern one to
movement creates small crevices in the centre of the zone, and small
mounds are created between their ends.
This development is very obvious in the landscape, such as in the
# 1 lies through a part of this zone, which stretches between the Olfus
County and the Selsund area near Mt. Hekla. The most recent
earthquake activity started around 4 o'clock in the afternoon of the
17th of June 2000 and has damaged a few houses in the Southwestern
Lowlands. On the 21st another equally strong, but shorter earthquake
struck the same area. Its epicentre was south of Mt. Hestfjall,
near the crossing of road #1 and the Skeid road. This one caused
much less property damage. The scientists are still waiting for
continuation. There have been no casualties.
a part of a much longer row of moraines pushed up by the Ice Age
glaciers about 9500 years ago.
Thjorsa Lava Field
about 7800 years old, 920 kilometres square, and 21 cubic kilometres in
is the largest lava field created during the last 10.000 years on the
earth and was emitted from craters in the Heljargja Area in the
the southernmost point of the country.
It was created in a similar way as the Island Surtsey and was
attached to the mainland with alluvium during the second latest warm
epoch of the Ice Age. On
the eastern part of the promontory, crater plugs are obvious.
Before this vast alluvial plain was
gradually created, a big and 250 m deep bay cut in between the
mountains. Two freestanding
hillocks, Stora- and Litla Dimon, were islands.
Grimsnes Lava Field was created during an extended volcanic period.
Ten lava fields were created at the time.
One of the craters, Kerid, looks like an explosion crater, but is
most probably a slag crater, which collapsed when the magma subsided at
the end of the eruption. Despite its small lake, it is not one of the Maar-craters.
Eyjafjallajokull erupted the last time 2010
and 1821-1823 and flooded the alluvial plain
following places appear in the Travel- and Angling Guides: