Powerful earthquake hits Tonga; tsunami advisory issued

WELLINGTON, New Zealand (AP) — A powerful underwater earthquake has struck off Tonga in the southern Pacific, prompting authorities to issue a tsunami advisory. The U.S. Geological Survey says the magnitude 7.3 quake was centered east-southeast of Neiafu, Tonga, at a depth of 15 miles. It predicted strong shaking but said the probability of serious damage or casualties was small. The U.S. Tsunami Warning System issued a tsunami advisory, which is one step below a tsunami warning. An undersea volcano erupted in Tonga in January, killing three people, blanketing its main island with a thick layer of volcanic ash and shooting millions of tons of water vapor high up into the atmosphere.