The residents of the small village of Grímsey, the most remote and the northernmost settlement in Iceland experienced yet another intense earthquake swarm overnight. The small island, which is located on the Tjörnes fracture zone, a highly active area off the north coast of Iceland, has seen several earthquake swarms in the past weeks.
According to the Seismic Monitoring System of the Icelandic Meteorological Office nearly 120 quakes, most between 1 and 2 on the Richter scale, were recorded in the intense swarm which began yesterday noon and lasted until shortly after midnight.
Read more: Why the constant earthquakes? Iceland is slowly being torn apart
Öræfajökull volcano was also hit with a sharp 3.6 magnitude quake early morning. The quake, which had an epicenter near the surface at a depth of only 100 m (330 ft), hit at 5:07 am, the IMO reports. Öræfajökull, which has been dormant for more than 200 years, has been showing signs of increasing activity in recent months. The summit of Öræfajökull is Hvannadalshnjúkur, the tallest peak in Iceland, standing at an elevation of 2,110 meters (6.920 ft).
Unconnected events
The quakes in Grímsey and Öræfajökull are unconnected and caused by two different forces. Grímsey is located on the Tjörnes rift zone, which is part of the North Atlantic Ridge. The area known for high geological activity, including geothermal and volcanic activity caused by the North American and Eurasian tectonic plates drifting in opposite directions. Energy builds up along the rift zone which is then released in earthquake swarms like the one which we saw yesterday.
The quakes in Öræfajökull volcano are of a different nature, and are caused by magma which is being thrust up toward the earth's surface. Unlike Bárðarbunga volcano, which has been very active in recent years, Öræfajökull does not have a large magma chamber close to the surface to store the magma. Scientists have therefore kept the volcano under close surveillance, as the activity is feared to signal growing likelihood of an eruption.
Iceland's second deadliest volcano
Öræfajökull covers a giant volcano which last erupted in 1727. A giant steam-blast eruption, also known as phreatic or ultravolcanian eruption, in 1362 eruption in Öræfajökull was the second deadliest eruption in Icelandic history. One of the best known steam-blast eruptions in history is the 1883 Krakatoa eruption. Steam-blast eruptions occur when magma heats ground water, creating a near-instantaneous evaporation and explosion which can eject enormous quantities of ash, rock and volcanic material which is then deposited over surrounding areas.
Read more: Emergency evacuation plan in case of eruption in Öræfajökull glacier
The 1362 Öræfajökull eruption destroyed one of the most prosperous farmland regions in South Iceland, killing all inhabitants and livestock at 20-40 farms in a region which was known then as Litla-hérað. Following the eruption, which deposited 10 cubic kilometers of volcanic material over fields and farms in the region, it's name changed to Öræfi, which translates as Wasteland in modern Icelandic.
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. The last eruption in 1727-28 was far smaller and caused only three fatalities.
The residents of the small village of Grímsey, the most remote and the northernmost settlement in Iceland experienced yet another intense earthquake swarm overnight. The small island, which is located on the Tjörnes fracture zone, a highly active area off the north coast of Iceland, has seen several earthquake swarms in the past weeks.
According to the Seismic Monitoring System of the Icelandic Meteorological Office nearly 120 quakes, most between 1 and 2 on the Richter scale, were recorded in the intense swarm which began yesterday noon and lasted until shortly after midnight.
Read more: Why the constant earthquakes? Iceland is slowly being torn apart
Öræfajökull volcano was also hit with a sharp 3.6 magnitude quake early morning. The quake, which had an epicenter near the surface at a depth of only 100 m (330 ft), hit at 5:07 am, the IMO reports. Öræfajökull, which has been dormant for more than 200 years, has been showing signs of increasing activity in recent months. The summit of Öræfajökull is Hvannadalshnjúkur, the tallest peak in Iceland, standing at an elevation of 2,110 meters (6.920 ft).
Unconnected events
The quakes in Grímsey and Öræfajökull are unconnected and caused by two different forces. Grímsey is located on the Tjörnes rift zone, which is part of the North Atlantic Ridge. The area known for high geological activity, including geothermal and volcanic activity caused by the North American and Eurasian tectonic plates drifting in opposite directions. Energy builds up along the rift zone which is then released in earthquake swarms like the one which we saw yesterday.
The quakes in Öræfajökull volcano are of a different nature, and are caused by magma which is being thrust up toward the earth's surface. Unlike Bárðarbunga volcano, which has been very active in recent years, Öræfajökull does not have a large magma chamber close to the surface to store the magma. Scientists have therefore kept the volcano under close surveillance, as the activity is feared to signal growing likelihood of an eruption.
Iceland's second deadliest volcano
Öræfajökull covers a giant volcano which last erupted in 1727. A giant steam-blast eruption, also known as phreatic or ultravolcanian eruption, in 1362 eruption in Öræfajökull was the second deadliest eruption in Icelandic history. One of the best known steam-blast eruptions in history is the 1883 Krakatoa eruption. Steam-blast eruptions occur when magma heats ground water, creating a near-instantaneous evaporation and explosion which can eject enormous quantities of ash, rock and volcanic material which is then deposited over surrounding areas.
Read more: Emergency evacuation plan in case of eruption in Öræfajökull glacier
The 1362 Öræfajökull eruption destroyed one of the most prosperous farmland regions in South Iceland, killing all inhabitants and livestock at 20-40 farms in a region which was known then as Litla-hérað. Following the eruption, which deposited 10 cubic kilometers of volcanic material over fields and farms in the region, it's name changed to Öræfi, which translates as Wasteland in modern Icelandic.
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. The last eruption in 1727-28 was far smaller and caused only three fatalities.
