But in Haast, residents took it all in their stride, describing it as "short and sharp" - if they felt it at all.
"The cats came screaming inside and a couple of glasses were rattling," Fantail Cafe owner Aly Brown said. "It was a mild, light shake that went on for a while."
Lee Rasmussen said, "I heard there was one," but he was asleep at the time and did not feel much. Nothing fell over or fell off the walls in his house.
Further north at the Waita River, Tony Kerr only found out about the quake when a radio station called to ask him about it.
"We were up, doing our usual thing. I was on the phone to my mother at about 7.30 and didn't feel anything."
Others told him later they felt the jolt, but for the most part it was a minor event.
"That's South Westland for you. We roll with the punches."
John Duberly, of Waiatoto River Safari, said: "It was just a jolt, and 10 or 15 seconds after that, a few tremors".
His double-storey house did not shake much and no pictures came off the walls.
"I didn't get out of bed, let me put it that way."
Close to the epicentre, Merv Velenski of Jackson Bay was surprised at the reports of a severe quake.
"Buggered if it felt like 5.3 to me. I'd have said half that.
"It only lasted a couple of seconds - a bit of a rumble and a bang, and then it was gone.
"There wasn't a plate rattled here or nothing."
He did not notice any large waves in the bay after the quake.
Haast police said no damage had been reported.
- The Greymouth Star
