WEWAK, PAPUA NEW GUINEA (BNO NEWS) -- A strong earthquake struck off the mainland of Papua New Guinea on late Monday morning, seismologists said. It was not immediately known if there were casualties.

The 6.8-magnitude earthquake at 9.38 a.m. local time (2338 GMT Sunday) was centered about 134 kilometers (83 miles) east of Wewak, the capital of the East Sepik province of Papua New Guinea. It struck about 16.8 kilometers (10.4 miles) deep, making it a shallow earthquake, according to the United States Geological Survey (USGS).

While there were no immediate reports about damage or casualties from the region, the USGS estimated that several hundred people may have felt 'very strong' to 'extreme' damage, which could potentially result in heavy damage. The agency further estimated that around 462,000 others may have felt moderate to strong shaking.

However, earthquakes in the mountainous nation of New Papua Guinea do rarely cause damage or casualties as most structures in the region are light and flexible. This allows them to bend, rather than snap when a major earthquake happens.

Because earthquakes below magnitude 7 do usually not generate tsunamis, no tsunami watches or warnings were issued by the Pacific Tsunami Warning Center (PTWC). It added that there was a small possibility of a local tsunami, a note of caution frequently included in PTWC bulletins.

Papua New Guinea, close to Indonesia, 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 July 1998, a powerful 7.0-magnitude earthquake struck just off the north coast of the country's island of New Guinea, causing a landslide which resulted in a local tsunami. The disaster left at least 2,183 people killed and thousands injured.

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