Norway

Norway's seismicity is low overall, though not entirely negligible given the country's size and the diversity of its geological environments. Two main mechanisms drive Norwegian earthquakes: postglacial rebound (isostatic adjustment following deglaciation ~10,000 years ago) generates scattered shallow events on ancient crystalline basement faults, particularly in northern and central Norway; and passive margin tectonics produce occasional events along the Norwegian continental shelf and the Jan Mayen Fracture Zone in the Arctic. The strongest Norwegian earthquakes in the instrumental record have occurred offshore: the 1904 Oslofjord earthquake (M 5.4) was the largest historical event near the Norwegian mainland and caused minor damage in the Oslo area. Svalbard, in the high Arctic, is occasionally affected by Arctic Ocean seismicity.

Paleoseismic investigations along Norwegian coasts have identified large postglacial faults — including the Stuoragurra Fault in Finnmark, one of the longest postglacial fault scarps in the world — that ruptured in events estimated at M 7+ in the early Holocene as the ice sheet retreated. These dramatic ruptures occurred as the sudden release of glacial loading stress allowed accumulated tectonic strain to be released in single events; they are not expected to recur at such large [[magnitude]] under present-day loading conditions.

Norway's seismic hazard is generally low enough that building codes do not require seismic design for most ordinary structures outside a few zones on the west coast and in the north. The country operates a national seismic network (NNSN) and participates actively in monitoring Arctic seismicity, which has additional relevance for Norway's offshore petroleum infrastructure.