The Storfjorden, Svalbard, Earthquake Sequence 2008–2020: Transtensional Tectonics in an Arctic Intraplate Region

Abstract An earthquake sequence in the Storfjorden offshore area southwest of Spitsbergen Svalbard archipelago initiated with a 21 February 2008 magnitude Mw 6.1 event. This had previously not produced any significant earthquakes, but between and 2020, total ?2800 earthquakes were detected, ?16 them being moderate size (ML?4.0). Applying double-difference relocation to improve relative locations reveals that activity is linked several subparallel faults striking southwest–northeast extend across entire crust. The trend also found as possible fault plane from regional moment tensor inversion. solutions range oblique normal center cluster pure strike slip farther away are consistent compressional ?1 axis roughly east–west direction plunging 57°, extensional ?3 subhorizontal trending north–south. mainshock steeply dipping southeast, other appear be near vertical. existence oblique, right-lateral strike-slip motion on southwest–northeast-trending component faulting events suggests transtensional tectonics around result activation complex system.