New Zealand was under a tsunami warning on Wednesday after a major earthquake with a magnitude of 7.8 struck off the west coast of its South Island, according to the U.S. Pacific Tsunami Warning Center.The quake struck around 8:22 p.m. local time (9:22 a.m. UTC) and its epicenter was located 161 km (100 miles) west of the city of Invercargill, according to the U.S. Geological Survey, which measures earthquakes around the world.The tsunami warning, which was issued as a precaution, applies only to New Zealand. The warning center said it is not known if a tsunami was actually generated by the quake.The tremor shook buildings in Queenstown and scared residents who ran into the streets, according to the New Zealand Herald.The quake, which was felt across South Island, downed power and phone lines, the newspaper reported.”It wasn’t very violent, more of a rolling feel,” Simon Darby, a resident of the inland town of Wanaka, told the Herald.”But it had a power about it, I ran straight outside into the carpark.”