Powerful earthquake off Indonesia triggers brief tsunami alert

[News_Editor]

Powerful earthquake off Indonesia triggers brief tsunami alert

2012-01-11 10:09:07 GMT+7 (ICT)

JAKARTA (BNO NEWS) -- A powerful earthquake struck off the Indonesian island of Sumatra on early Wednesday morning, seismologists said, prompting a brief tsunami alert but causing no damage.

The 7.1-magnitude earthquake at 12.37 a.m. local time (1837 GMT Tuesday) was centered about 423 kilometers (262 miles) southwest of Banda Aceh, the capital of Aceh province on the northern tip of Sumatra. It struck about 10 kilometers (6.2 miles) deep, making it a shallow earthquake, according to Indonesia's seismological agency (BMKG).

The United States Geological Survey (USGS) measured the strength of the earthquake at 7.3 on the regional moment magnitude (Mw) scale with a depth of 29.1 kilometers (18.1 miles). BMKG initially measured the quake at 7.6 on the Richter scale but later revised it downwards.

Tremors could be felt in Banda Aceh where residents fled from buildings and rushed to higher ground as BMKG issued a tsunami warning for local coastlines. The warning was canceled about two hours later when no unusual waves were observed.

Provincial officials said there were no immediate reports of damage, and most people returned to their homes when the tsunami warning was canceled. The USGS estimated that approximately 882,000 people in the region may have felt light to moderate shaking.

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 the region.

On December 26, 2004, one of the most powerful earthquakes ever recorded struck off the west coast of Sumatra in Indonesia. The 9.1-magnitude earthquake unleashed a deadly tsunami, striking scores of countries in the region. In all, at least 227,898 people were killed.

Most recently, on October 25, 2010, a powerful 7.7-magnitude earthquake struck just off the Mentawai Islands off the western coast of Sumatra. As a result, a wall of water killed at least 435 people on the islands and impacted more than 20 villages.

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