Grimsvotn (Iceland's Deadliest Volcano) is in the middle of Vatnajokull Glacier
Posted by JAC on 4/18/2010, 7:36 pm



http://en.wikipedia.org/wiki/Gr%C3%ADmsv%C3%B6tn

http://www.volcano.si.edu/world/volcano.cfm?vnum=1703-01=&volpage=erupt


Grímsvötn, Iceland's most frequently active volcano in historical time, lies largely beneath the vast Vatnajökull icecap.

The caldera lake is covered by a 200-m-thick ice shelf, and only the southern rim of the 6 x 8 km caldera is exposed.

The geothermal area in the caldera causes frequent jökulhlaups (glacier outburst floods) when melting raises the water level high enough to lift its ice dam. Long NE-SW-trending fissure systems extend from the central volcano.

The most prominent of these is the noted Laki (Skaftar) fissure, which extends to the SW and produced the world's largest known historical lava flow during an eruption in 1783.

The 15-cu-km basaltic Laki lavas were erupted over a 7-month period from a 27-km-long fissure system.

Extensive crop damage and livestock losses caused a severe famine that resulted in the loss of one-fifth of the population of Iceland.










Grimsvotn is basically just an enormous pit, a 5 mile (8 km) diameter caldera located near the center of the Vatnajokull icefield.

An ice-covered lake fills the lowest southern part of the caldera, and the steep escarpment of Grimsfjall rises over 1200 ft (360 m) above it to the summit.

Vatnajokull is the largest icefield in Europe, over 3200 square miles (8300 sq km) in area, and the traverse on skis is a classic multiday adventure.

The north-south distance is about 50 miles (80 km), while east-west it is over 75 miles (120 km), and the several possible traverse routes all converge at a hut located on Grimsfjall.

Several other huts are located near the north, south, east, and west edges of the icefield for use by traverse expeditions.

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Iceland earthquakes - CypressTX, 4/18/2010, 5:12 pm
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