Localization of microearthquakes recorded at 8°E on Gakkel Ridge, Arctic Ocean, by seismic arrays on drifting ice floes

Seismic activity on mid-ocean ridges is often relatd to active tectonic, magmatic or hydrothermal processes. The investigation and localization of seismic activity on mid-ocean ridges is therefore an established geoscientific approach to better understand the active processes of crustal generation on mid-oceanic ridges. In the summer 2007, during the AGAVE (Arctic Gakkel Vents Expedition) 12 seismometers were deployed for 4 days on drifting ice floes above the Arctic Gakkel Ridge around 8°E. The recorded seismic data contained 55 microearthquakes that could be localized in the survey area. The important sources of localization uncertainties are discussed and it was found that the accuracy of the localization results greatly depends on the quality of the seafloor batyhmetric data available. The localization results are geologically interpreted on the basis of seafloor topography. It was found that the seismicity is symmetrically distributed on both sides of the central rift valley and most of the events are originated in shallow source depths.The results of this study will complement the results of similiar projects, conducted at other segments of the Gakkel Ridge.