Tsunami watch cancelled in Indian Ocean following two earthquakes April 11, 2012

These quakes were off the coast of northern Sumatra in Indonesia, where a 9.1-magnitude quake on December 26, 2004 triggered a tsunami that killed 230,000 people.

The Pacific Tsunami Warning Center in Hawaii has now cancelled the tsunami watch issued earlier today (April 11, 2012) after an 8.7 magnitude earthquake and 8.2 magnitude aftershock in the Indian Ocean. These two large earthquakes took place off the west coast of northern Sumatra in Indonesia. The first quake struck at 8:38 UTC today. The aftershock, which was south of the first quake, struck at 10:43 UTC. The Pacific Tsunami Warning centered was quoted by the BBC as saying:

…the threat has diminished or is over for most areas.

The Pacific Tsunami Warning Center cancelled the watch at 12:36 UTC today. They had previously issued the watch for Indonesia, India, Sri Lanka, Australia, Myanmar, Thailand, the Maldives and other Indian Ocean islands, Malaysia, Pakistan, Somalia, Oman, Iran, Bangladesh, Kenya, South Africa and Singapore. A “watch” means there is the potential for a tsunami. The Pacific Tsunami Warning Center never issued a “warning” for this event, which would have meant a tsunami was imminent, but the governments of some coastal nations surrounding the Indian Ocean did issue tsunami warnings. There has been no report of major destruction from coastal tsunamis or any deaths. However, many media reported there was “panic” in coastal areas in Sumatra, as residents packed the roads attempting to flee to higher ground.

Read tsunami watch cancellation issued 12:36 UTC today from the Pacific Tsunami Warning Center

According to the Washington Post, the earthquake was felt in Singapore, Thailand, Bangladesh, Malaysia and India.

Here are the specifics of the 8.7 magnitude earthquake, according to the U.S. Geological Survey (USGS):

Date/Time Wednesday, April 11, 2012 at 08:38:38 UTC
Wednesday, April 11, 2012 at 02:38:38 PM at epicenter
Location 2.348°N, 93.073°E
Depth 33 km (20.5 miles)
Region OFF THE WEST COAST OF NORTHERN SUMATRA
Distances
434 km (269 miles) SW of Banda Aceh, Sumatra, Indonesia
550 km (341 miles) SW of Lhokseumawe, Sumatra, Indonesia
963 km (598 miles) W of KUALA LUMPUR, Malaysia
1797 km (1116 miles) WNW of JAKARTA, Java, Indonesia

Here are the specifics of the 8.2 magnitude earthquake, according to USGS:

Date/Time Wednesday, April 11, 2012 at 10:43:09 UTC
Wednesday, April 11, 2012 at 04:43:09 PM at epicenter
Location 0.773°N, 92.452°E
Depth 16.4 km (10.2 miles)
Region OFF THE WEST COAST OF NORTHERN SUMATRA
Distances
618 km (384 miles) SSW of Banda Aceh, Sumatra, Indonesia
712 km (442 miles) W of Sibolga, Sumatra, Indonesia
1062 km (659 miles) WSW of KUALA LUMPUR, Malaysia
1773 km (1101 miles) WNW of JAKARTA, Java, Indonesia

The 8.7 magnitude quake took place 434 kilometers (269 miles) from Banda Aceh in Sumatra, Indonesia, the site of three-quarters of the deaths from the 2004 earthquake and tsunami in Indonesia.

Bottom line: An 8.7 magnitude earthquake in the Indian Ocean today (April 11, 2012) triggered a tsunami watch, but Pacific Tsunami Warning Center officials said later that the tsunami, although measurable, “does not look major.” An 8.2 magnitude aftershock followed the original quake by just over two hours. A watch means there is the potential for a tsunami, not that one is imminent. The quake happened the same area where a 9.1-magnitude earthquake in late 2004 caused a tsunami that killed 230,000 people.

Deborah Byrd

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