New Zealand was reportedly hit by an aftershock west of Christchurch, scene of a 6.3-magnitude earthquake in February that killed 181 people.
No serious damage or injuries were reported from the 5.5-magnitude quake that according to the U.S. Geological Survey struck Monday morning, 13 miles west of Christchurch at a depth of 2 miles.
The Canterbury Quake Live website reported the shake was the sixth largest since a 7.1-magnitude quake that struck New Zealand last September, the BBC reports.
That quake — the same magnitude as the earthquake that flattened much of Port-au-Prince, Haiti, in January 2010 — released roughly 11 times the energy of the February quake, but killed no one, according to the CSM.
Scores of aftershocks have followed the devastating February earthquake, the AP reports. The quake was also New Zealand's most expensive natural disaster, costing an estimated $15 billion.
Monday's quake, which knocked goods off supermarket shelves, has increased nervousness in the city, the BBC reports.
The BBC interviewed Fay Burson, manager of bottle store Henry's in Rolleston, as saying she had probably lost more stock in the latest shock than in February. "It was a very severe initial jolt after a bit of a lull."
Spectators and players at a rugby tournament, meanwhile, reported seeing the ground "roll."
"Everyone stopped and looked, then carried on. Everyone's come to expect them now," Rolleston Rugby Club president David Egan said, the BBC reported.