In the city of Karimabad, in Gilgit-Baltistan, a witness who gave his name as Anas told the BBC that the quake had sent a landslide crashing into the Hunza river.
"At first it was as if someone was shaking us. There were about 20 of us and we just held on to each other," he said.
"Right after that we saw a major landslide. Some people say it was a glacier that came down, some people say it was a hill. It fell right in front of our eyes."
Officials said the quake happened at a depth of 212km. The magnitude was initially put at 7.7 but later downgraded.
An aftershock measured at 4.8 magnitude struck shortly afterwards.