Segment?Scale Seismicity of the Ultraslow Spreading Knipovich Ridge

Ultraslow spreading ridges form the slowest divergent plate boundaries and exhibit distinct processes in volcanically active magmatic sections intervening amagmatic sections. Local seismicity studies of ultraslow until now cover only parts segments give insight into at confined locations. Here, we present a microseismicity data set that allows to study on scale entire segments. Our network 26 ocean bottom seismometers covered around 160 km along axis Knipovich Ridge Greenland Sea recorded earthquakes for period about 1 year. We find varying distinctly along-axis. The maximum earthquake depths shallow over distances 70 toward Logachev volcanic center. swarm activity occurs an otherwise aseismic zone. Melts may thus be guided subparallel topography lithosphere-asthenosphere boundary major centers explaining uneven along-axis melt distribution typical ridges. Absence upper 8 lithosphere with band deep underneath offsets presumably melt-poor regions from magma richer Aseismic deformation these indicate weakening mantle rocks by alteration. do not obvious indications detachment faulting characterizes magma-poor some highly oblique reason fine-scale segmentation seismic zones weak possibly indicating transform motion short obliquely oriented faults.