An earthquake of 6.2 magnitude -- the biggest in Norwegian history -- jolted the sparsely populated Svalbard archipelago in the Arctic on Wednesday night, the Norsar seismic research institute said on Thursday. "This is the biggest earthquake on Norwegian territory in history," the institute said in a statement. "The earthquake happened at sea about 10 km (six miles) below the surface, and was felt strongly in (the Norwegian town of) Longyearbyen."