AGAVE2007
A lonely seismic station on an ice floe
Our pilot study during AMORE2001 showed that it is possible to record microearthquakes with land seismometers deployed on drifting ice floes. As only one seismic arrays was used for the tests during the AMORE cruise, the accuracy of earthquake epicentre locations remained limited. The project MOVE now undertakes a systematic analysis of the microearthquake activity of Gakkel Ridge to study its active magmatic and tectonic processes. To improve the detection and location capabilities, we use a network of three arrays and aim at recording times of at least 14 days per rift segment.
As part of an international IPY project, the Arctic Gakkel Vents Expedition 2007 (AGAVE2007) onboard the Swedish icebreaker ODEN investigated two hydrothermal vent sites at the ultraslow-spreading Gakkel Ridge: a peridotite hosted site in the Sparsely Magmatic Zone near 7°E and the prominent volcanic complex at 85°E active in 1999 and 2001 (see AMORE2001).
Installing a seismometer station on an ice floe
While the ship operations were dedicated to the vent exploration, we used the ship's helicopter to install three seismological arrays on ice floes in the rift valley around the vent sites. On each ice floe, four short-period three-component seismometers were mounted on wooden plates, sheltered with a bucket and covered with a heap of snow. A battery powered data logger with GPS time and position recorded continuously the ground motion. An ARGOS satellite transmitter on each ice floe allowed us to track the position of the ice floes as they drifted through the survey area and guaranteed safe recovery of the stations.
The data set includes a variety of local and regional earthquakes which we have now started to analyse.
