One of these, the 30 km-long row of craters, Lakag gar, with about 100 separate craters, erupted in 1783. The lava flow from this eruption is the largest recorded in the world, covering 565 square km. The gases and ash from this eruption poisoned the grasslands, causing tremendous havoc to the countryside. The resulting damage to the farmland brought widespread famine to Iceland resulting in the deaths of tens of thousands through starvation. Shield volcanoes of the Hawaiian type, like Skjaldbrei ur near ingvellir, are also numerous, but the only one active in historical times was the new Surtsey volcano.
Craters created by volcanic explosion are also quite common.
The most famous Icelandic volcano is Hekla, which was renowned throughout the Catholic world in the Middle Ages as the abode of the damned. Since its first recorded eruption in 1104, which destroyed vast areas, including the j rs rdalur settlement, Hekla proper has erupted 17 times in historic times, continually causing damage to the surrounding countryside. At the beginning of its eruption in March 1947, columns of smoke and ash rose to 100,000 feet. The eruption lasted 13 months. In May 1970, a number of small craters in Hekla erupted, the lava flow lasting for a couple of months.