"This is the biggest earthquake on Norwegian territory in history," the institute said in a statement, adding that the quake occurred at sea, about 10 km (6 miles) below the surface.
Anne-Karin Bekken, one of roughly 2,000 residents of the archipelago's main town Longyearbyen, said she and her boyfriend were jolted awake by the earthquake.
"We woke up and everything was shaking. It was a bit scary," she told Reuters over the telephone.
"Before I realized what it was, it was over. I thought it was the blizzard blowing the house into pieces," said Bekken, a consultant at the local coal mine.
Norsar said Svalbard registered several aftershocks, and predicted there would be more.
