In contrast to Gakkel Ridge, Lena Trough is a very young mid-ocean ridge system that opens obliquely to the orientation of the ridge. The land masses of Greenland and Svalbard are close by and were originally moved laterally past each other along a major shear zone which developed into the modern Spitsbergen Fracture Zone. The opening of Fram Strait and hence the onset of seafloor spreading at Lena Trough about 10 million years ago is of major interest because the deep rift valley constitutes the only deep water passage connecting the Arctic Ocean basin with other oceans. Today, earthquakes still document complicated opening processes: earthquakes are unevenly distributed and scattered far beyond the topographic rift axes. The Spitsbergen Fracture Zone has demonstrated in a recent magnitude 6.5 earthquake in March 2009 that it is capable of very large stress build-up.