Three undersea quakes hit southern Philippines

Three strong undersea tremors struck several parts of southern Philippines on Thursday but there were no reported damages and no tsunami alerts issued either, according to the United States Geological Survey ( USGS).

The latest 4.5-magnitude earthquake, with a depth of about 620. 9 km, occurred around 7:30 p.m. and was traced 110 km southwest of southern city of Cotabato.

Barely three hours before that, a 5.1-magnitude earthquake with a depth of 623.1 km and with epicenter of 110 km southwest of Cotabato jolted the cities of Pagadian and Zamboanga, the USGS reported.

At around 3:30 p.m., a 6.4-magnitude tremor traced about 150 km south of Pagadian City with a depth 618.8 km jolted several parts of Mindanao.

There were no tsunami alerts issued by the Pacific Tsunami Warning Center based in Hawaii.

Philippine Institute of Volcanology and Seismology director Renato Solidum said the three quakes were almost not felt by people because it was too deep to cause any damages.

He said Thursday's tremors were also part of aftershocks of July 24 strong quakes within Moro gulf off Mindanao Island.

Mindanao was frequently hit by earthquakes in the last few days.

On Saturday, three major earthquakes occurred in the south with more than 200 aftershocks but there were no reported damages.

The Philippines sits on the Pacific "Ring of Fire" where continental plates collide causing frequent seismic and volcanic activity.

The deadliest earthquake in the country happened on August 16, 1976 when a tsunami caused by the quake killed between 5,000 and 8, 000 people in the Moro Gulf region in southern Philippines.

Source: Xinhua