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Saturday, October 08, 2011

Reykjanes Ridge Earthquakes Coincide With Rise In Seismic Activity At Katla Volcano

Reykjanes Ridge Earthquakes Coincide With Rise In Seismic Activity At Katla Volcano

By Mark Dunphy - Fri Oct 07, 12:05 pm

Reykjanes Ridge and Katla marked on Google Earth
Reykjanes Ridge and Katla marked on Google Earth

The Reykjanes Ridge, the part of the Mid-Atlantic Ridge that rises up to the ocean surface to the southwest of Iceland, has been hit by a series of earthquakes during the past 48 hours. The quakes have coincided with a surge in seismic activity in the vicinity of the Katla volcano in the south of Iceland.

The European Mediterranean Seismological Center (EMSC) has recorded at least eight subsea earthquakes about 850 kilometres southwest of the Icelandic capital of SW Reykjavík (pop 113,906).

The strongest of the quakes, a magnitude 5.7, was located 892 km southwest of the Icelandic capital Reykjavík. It hit at 00:39 GMT and was measured at a depth of just 10km, according to the EMSC.

Meanwhile, the Icelandic Meteorological Office noted that an earthquake swarm occurred underneath the Mýrdalsjökull glacier in south Iceland on Wednesday and Thursday.

Approximately 30-40 earthquakes were recorded on Wednesday and Thursday. The strongest earthquake measured ML3.55 and was measured to have hit at a depth of 1 kilometre. Seismic activity has since subsided. Only six earthquakes have been recorded at Mýrdalsjökull between 0000hrs and 1200hrs on Friday.

Geophysicist Benedikt Ófeigsson told visir.is said that while the situation is being constantly monitored, it has not been considered necessary to alert Iceland’s Civil Defense Department.

In recent weeks residents of Vik (population 300 approx.), located at the foot of Katla, have participated in emergency evacuation drills in the event of a volcanic eruption and subsequent glacial floods affecting the small coastal town.

Vik, Iceland. Image Progresschrome
Vik, Iceland. Image Progresschrome

About Katla

Katla is located on the Mýrdalsjökull glacier which is the southernmost glacier in Iceland and is almost 600 km2. It is situated to the north of Vík í Mýrdal and to the east of the smaller glacier Eyjafjallajökull, where an eruption in 2010 caused major disruptions to airtraffic throughout western and northern Europe in April and May 2010. The caldera is 10 km (6 mi) diameter and is covered with 200–700 metres (660-2,300 ft) of ice.

Sixteen eruptions have been documented at Katla between 930 and 1918 at intervals of 40–80 years. It has not significantly erupted for 93 years, although there may have been small eruptions that did not break the ice cover in 1955 and 1999. The 1918 eruption resulted in extending the southern coast by 5 km due to laharic flood deposits.

Locations of caldera rim and previous eruptions. Image RicHard-59
Locations of caldera rim and previous eruptions. Image RicHard-59

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