SINGAPORE - A powerful earthquake of magnitude 6.8 struck northeast of the South Pacific island nation of Tonga on Tuesday, the United States Geological Survey said, but a destructive tsunami was not expected.

The quake's epicenter was recorded 195 km (120 miles) east-northeast of the Tongan capital Nuku'Alofa at a depth of 61 km (38.5 miles), it said.

There were no immediate tsunami warnings issued, according to websites for the USGS (www.here) and the Hawaii-based Pacific Tsunami Warning Center (PTWC) (www.prh.noaa.gov/ptwc/).

Based on all available data, a destructive Pacific-wide tsunami is not expected and there is no tsunami threat to Hawaii, the PTWC said in a statement.

There were also no reports of damage or injury about half an hour after the quake was recorded at 1247 GMT, or about 2.47 a.m. on Wednesday local time.

Tonga was one of three South Pacific nations hit by four tsunamis generated by 8.0 magnitude quake in late September. Almost 200 people were killed in Samoa, American Samoa and Tonga, the majority in Samoa.

Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire, a zone of frequent earthquakes and volcanic eruptions.

It is the location of the 10 strongest earthquakes in the world since 1900, all of which registered a magnitude of 8.5 or above.

Tsunami Earthquake Quake