There was no tsunami threat for Tonga following a powerful earthquake east of the Fiji islands this morning, the Tonga Meteorological Office advised. The earthquake has been rated by Global tectonic reports among the largest deep focus earthquakes ever observed and was one of ten earthquakes over M 4.3 recorded in the region east of Fiji today.

The earthquake with a preliminary Magnitude of 8.1 occurred at 5:18 am (Tonga time) today, September 7, located 118km ESE of Suva at a depth of 669.1km.

"There is no tsunami threat because the earthquake is located too deep inside the earth," the NWS Pacific Tsunami Warning Center at Ewa Beach, Hawaii stated.

According to a United States Geological Service tectonic summary, the large earthquake just offshore of the islands of Fiji, about 900km to the west of the Tonga Trench, occurred in response to stresses generated by the slow distortion of the Pacific plate at depth. They noted that a similar large earthquake on August 19 was followed by about 150 aftershocks.

This morning's Fiji earthquake was similar in size to the largest observed deep focus earthquakes. (The largest deep-focus earthquake ever recorded was an M 8.3 event in 2013 off Russia.)

"Over the past century, 96 earthquakes with a magnitude of M 7+ have occurred at depths greater than 300 km globally; six of these were located in the same region as the September 6 [7], 2018, event. The largest nearby event at these depths was a M 8.2 earthquake on August 19, 2018.

Deep-focus earthquakes cause less damage on the ground surface above their foci than similar-magnitude shallow-focus earthquakes, but large deep-focus earthquakes may be felt at great distance from their epicenters.