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- A tsunami warning was issued as an undersea quake which measured 7.5 on the Richter scale struck -

The quake occured in The Talaud Islands near the Philippine island of Mindanao, Jakarta. It occurred beneath the ocean at a depth of 20 miles (33 km).

The meteorology agency released the news on Thursday and warnings were put in place. Earthquakes of this magnitude can often trigger local tsunamis which can affect coastal areas within 100km of the quake’s epicentre.

The U.S. Pacific Tsunami Warning centre said they did not consider there to be a danger of widespread tsunami threat and lifted the warning an hour later.

“Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Such large vertical movements of the earth’s crust can occur at plate boundaries.

Subduction earthquakes are particularly effective in generating tsunamis, and occur where denser oceanic plates slip under continental plates in a process known as subduction”.

The country is prone to seismic upheaval due to its location on the so-called Pacific “Ring of Fire”, an arc of volcanoes and fault lines around the Pacific Basin”.

The means for measuring the intensity of an earthquake was invented by Charles F. Richter, a U.S. seismologist in the 1900’s. It works on a scale which ranges from 1to 10; 10 being the most intense.

So this quake at 7.5 was quite a high intensity and “Japan’s meteorological agency may issue tsunami messages for countries in the northwest Pacific and South China Sea.

If the information was conflicting, the more conservative information should be used for safety purposes”.

The 2004 Indian Ocean earthquake was an undersea earthquake that occurred at 00:58:53 UTC on December 26, 2004, with an epicentre off the west coast of Sumatra, Indonesia.

It triggered a series of devastating tsunamis along the coasts of most landmasses bordering the Indian Ocean, killing more than 225,000 people in eleven countries, and inundating coastal communities with waves up to 30 meters (100 feet) high.

It was one of the deadliest natural disasters in recorded history. Indonesia, Sri Lanka, India, and Thailand were hardest hit. The Asian Tsunami, or Boxing Day Tsunami, was one of the most severe in living memory.

With a magnitude of between 9.1 and 9.3, it is the second largest earthquake ever recorded on a seismograph and triggered other earthquakes as far away as Alaska.

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