Several powerful earthquakes hit near the coast of New Zealand on Thursday night and Friday morning, prompting tsunami warnings for New Zealand and tsunami watches for Hawaii.

The most powerful was an 8.1 quake that hit some 620 miles northeast of New Zealand on Friday morning, the U.S. Geological Survey said. Two earlier quakes registered magnitude 7.4 and magnitude 7.3.

There were no immediate reports of serious damage or casualties.

While the quakes triggered warning systems and caused traffic jams and some chaos in New Zealand as people scrambled to get to higher ground,