Jan Mayen Seismic station

 

The stratovolcano Beerenberg, is the northernmost active subaerial volcano on Earth.
The upper part of Beerenberg is covered by an ice cap, which sends glacial tongues in all directions.
Several of these are typical outlet glaciers and 5 of them calve into the sea, 2 on the eastern coast and 3 on the northwestern coast.

Map based on
Imsland (1986)
Map based on
Sylvester (1975)
Eruption areas
1970/1985


Beerenberg is in a fairly unusual tectonic setting near the intersection of the
Jan Mayen Fracture Zone (a transform fault) and the Mohns mid-ocean ridge.
The Kolbiensey Ridge is 170 km to the east.

Beerenberg has erupted six times between 1732 and 1985. All of these eruptions were on flank vents and produced lava flows and scoria cones. The most recent eruptions were in 1970, 1973, and 1985.

The 1970 eruption began on September 18 and continued to January, 1971. Intense storms hid the onset of the eruption. A commercial pilot spotted the eruption cloud on September 20.
It was the only historic eruption witnessed in modern times. The eruption was large, erupting at least 0.5 km³ of basalt from a 6 km long fissure that ran from sea-level to an elevation of 1,000 m. There were at least five active craters.

Photos from the 1970 eruption

Photo: C.A. Gløersen Photo: C.A. Gløersen Photo: C.A. Gløersen Photo: C.A. Gløersen
22-23 Sep. 1970
22-23 Sep. 1970
22-23 Sep. 1970
22-23 Sep. 1970
Photo: C.A. Gløersen Photo: C.A. Gløersen Photo: C.A. Gløersen Photo: C.A. Gløersen
22-23 Sep. 1970
+30C warm sea !
Radarmap after
the eruption
22-23 Sep. 1970

The 1985 eruption began on January 6, 1985 and lasted only 35-40 hours. In that brief time about 7 million m³ of lava was erupted (enough to bury a football field in 1400 m of lava!).
Earthquakes, with magnitudes up to 5, occurred during the eruption. The eruption was thought to be from a leaky fracture zone not the Jan Mayen magma system proper (Imsland, 1986). The vent was 35 km from the settlement.

The Department of Earth Science, University of Bergen has operated seismic stations on Jan Mayen (as part of the National Seismic Network of Norway) since 1961 http://www.geo.uib.no/Seismo/ The 3 stations on Jan Mayen (Olonkin City , Ulla and Liberg) are use to make daily locations of the local seismicity as well as recording far away earthquakes http://www.geo.uib.no/Seismo/nnsn/index.html The seismic network on Jan Mayen serves as an important monitor of the activity of Beerenberg and surrounding area.

Also other field expeditions visited Jan Mayen in August 1973 in connection with  search for magma chambers beneath the island.
http://www.geol.ucsb.edu/faculty/sylvester/JAN%20MAYEN/JanMayenHome.html

 Photo: Per-Einar Dahlen - September 2002
Ulla: Antenna, sensor and radio hut.
Solar panel and wind generator charges 315AH/12V battery.


Norsar logo
NORSAR has been established as the Norwegian National Data Center (NDC) for treaty verification for the Comprehensive Nuclear-Test-Ban treaty (CTBT). Seismic datas are sent continiously from Jan Mayen to Norsar. Here is last seismic activity at JMI.

Photo: Stein Henrik Olsen - 2000. Top of Beerenberg 2277m asl Seismoroom - (Bent Eirik Pedersen) Photo by Gunnar Utkilen Photo by Børre Nilsen
Sentralkrateret
Seismoroom
(2000)
Digging...
(2000)
Beerenberg smoke
(1985)