A tremendous eruption started on March 29, 1875 in Askja, in Northeast Iceland, north of Vatnajökull gacier and south of Heiðubreið mountain. The volcanic ash was heavy enough to poison the land and kill livestock, especially in the East Fjords of Iceland. The ash from the eruption was carried with the wind to Norway and Sweden.
The eruption is thought to have contributed to a wave of emigration from Iceland to North America. In the 1875 eruption a new lake was formed, Öskjuvatn. It is the deepest lake in the country, possibly with the exception of Jökulsárlón glacial lagoon.
Lake Öskjuvatn. Photo: Benedikt Jóhannesson.
Askja erupted again on October 26, 1961 but this was a minor eruption and lasted only a few days. Askja is at the northern end of the intrusive dike stretching from Bárðarbunga through Holuhraun.
In 1907, the German scientists Walter von Knebel and Max Rudloff visited Askja to study the caldera. While exploring Öskjuvatn in a small boat, they disappeared without a trace. Von Knebel's fiancée Ina von Grumbkow led an expedition to search for them, but no indication of what happened to them was ever found.
Recent observations on the effects of a landslide, on July 21, 2014, has led to renewed speculation that the scientists were killed by a similar sudden event, as the result of a massive wave similar to the one seen in 2014, which was estimated to be 50 metersn (164 feet) high.