Magnitude-6.4 earthquake hits off Tonga, no tsunami threat

A strong earthquake with a preliminary magnitude of 6.4 has struck
the Pacific Ocean off Tonga, U.S. seismologists say. Damage is not expected and no tsunami warnings have been issued.

The earthquake, which struck at 12:08 p.m. local time on Monday, was centered about 84 kilometers (52 miles) north of Nuku’alofa, the kingdom’s capital. It struck at a depth of 100 kilometers (62 miles), making it a relatively deep earthquake.

The United States Geological Survey (USGS) put the preliminary magnitude of 6.4. Because of the location and depth of the earthquake, serious damage and injuries is unlikely.

Computer models from the USGS estimate that up to 129,000 people could have felt the earthquake, including 1,000 people who may have felt “moderate” shaking and 91,000 who may have felt “light” shaking.

No tsunami alerts were issued after the earthquake, which was initially measured at 6.5.

Tonga is on the so-called ‘Pacific Ring of Fire,’ an arc of fault lines circling the Pacific Basin that is prone to frequent and large earthquakes. Volcanic eruptions also occur frequently in the region, which is one of the most geologically active parts in the world.

Tonga, with a total population of around 104,000 people, is made up of 169 islands sprinkled over the Pacific Ocean about one-third of the way from New Zealand to Hawaii. Only thirty-nine of the islands are inhabited, but many of its residents live in structures that are vulnerable to earthquakes.

On September 29, 2009, an 8.1-magnitude earthquake struck 185 kilometers (115 miles) east-northeast of Hihifo on Tonga, unleashing large tsunamis that killed nearly 200 people and injured hundreds more in Tonga, American Samoa, Samoa, and other nearby island nations.