New Zealand was rattled by aftershocks Friday following a 7.8-magnitude earthquake earlier this week. Two aftershocks, measuring 5.3 and 5.6, shook residents awake early Friday at the south end of the South Island, according to New Zealand's GNS Sciences, which monitors quakes. Wednesday's quake, the largest recorded in New Zealand in 80 years, was centered off the west coast of the South Island at a depth of only 7.5 miles (12 kilometers). No major damage has been found in the sparsely populated Fiordland on the west coast of the South Island. Martin Reyners, principal scientist for GNS Sciences, said a shallow temblor of such magnitude would typically cause widespread damage and loss of life. Wednesday's quake, however, occurred in soft rocks'' between two tectonic plates, muffling its power. Reyners said the rocks lurched rather than snapped, causing a low-frequency rolling rather than the high-frequency waves which damage buildings. It's a good reminder to New Zealanders that we have had earthquakes this size in the past ... and sooner or later we will have one in a more populated area,'' he said.