A sharp earthquake swarm was detected in Öræfajökull, one of Iceland's most powerful volcanoes. More than two dozen tremors have been recorded, including a relatively powerful 3.0 magnitude quake at 21:15 yesterday, Friday evening.
Volcano kept under close surveillance According to the Seismic Monitoring System of the IMO the epicenter of yesterday's quake was in the southeastern part of the volcano's caldera at a depth of only 200 m (660 ft). Historically earthquakes have been extremely rare in Öræfajökull, but recently it has been showing significantly greater levels of activity.
Öræfajökull is the southernmost part of Vatnajökull glacier. Its summit, Hvannadalshnjúkur, is the tallest peak in Iceland, standing at an elevation of 2,110 meters (6.920 ft). Öræfajökull glacier covers a giant volcano which last erupted in 1727. Following this eruption the volcano was completely dormant until a couple of years ago when it started to show activity again.
Öræfajökull erupts in steam-blast eruptions, also known as phreatic eruptions. In addition to the 1727 eruption it has erupted only once since Iceland was settled in the Viking Age. In 1362 Öræfajökull erupted in the second deadliest eruption in Icelandic history, destroying one of the most prosperous farmland regions in South Iceland, killing all inhabitants and livestock at 20-40 farms.
The volcano is not particularly active, erupting at an interval of several hundred years. The 1362 eruption is considered to be the largest tepthra eruption in the world in the last 1000 years.
Photo: SVÍNAFELLSJÖKULL GLACIAL LAGOON One of the outlet glaciers of Öræfajökull. The giant volcano is covered by the southernmost part of Vatnajökull glacier. Photo/Jói K.