BackgroundHekla is located near the southern end of the eastern rift zone. It sits on a rift-transform junction, and has produced basaltic andesites, in contrast to the tholeiitic basalts typical of Icelandic rift zone volcanoes. Hekla's tephras are generally rich in flourine, which is very hazardous to grazing animals.
The elongated shape of the volcano is caused by a 5.5-km-long fissure, Heklugjá, that cuts across the volcano and is often active along its full length during major eruptions. Repeated such eruptions, oblique to most rifting structures in the eastern volcanic zone, have created Hekla's elongated ENE-WSW profile.
Frequent large explosive eruptions during historical times have deposited tephra throughout Iceland and provide important time markers that can be used to date eruptions from other volcanoes in Iceland.
See also: Sentinel hub | Landsat 8