Major 7.4-magnitude quake hits near Japanese islands: USGS

December 22, 2010

– Tue Dec 21, 2:21 pm ET

TOKYO (AFP) – A major 7.4-magnitude quake struck southern Japan Wednesday, the

US Geological Survey said, with people in nearby coastal regions told to

evacuate as a foot-high tsunami rolled in.

The quake hit at 2:19 am local time (1719 GMT Tuesday), 153 kilometres (95

miles) east of Chichi-shima in Japan's remote Bonin island region and at a

shallow depth of just 14 kilometres.

There were no immediate reports of damage or injury but a tsunami of 30

centimetres (one foot) hit the island chain, according to Japanese television

broadcasts.

The meteorological agency had warned that two-metre waves were expected to hit

the archipelago, known locally as the Ogasawara islands, and told people living

near the coast to evacuate to higher ground.

But Japan later downgraded the alert to a warning of small waves.

The Bonin island chain, made up of more than 30 subtropical and tropical islets

some 1,000 kilometres south of Tokyo and 240 kilometres north of Iwo Jima, have

a population of just 2,700, according to the 2005 national census. The

Hawaii-based Pacific Tsunami Warning Center said there was no threat of a

destructive widespread tsunami and no nearby islands are thought to be in the

tsunami danger zone.

But it warned in a bulletin: " Earthquakes of this size sometimes generate local

tsunamis that can be destructive along coasts located within 100 kilometres of

the earthquake epicentre.

" Authorities in the region of the epicentre should be aware of this possibility

and take appropriate action. "

The quake was followed just over 20 minutes later by two aftershocks, a minute

apart, of 5.6-magnitude just 10 kilometres deep, followed by two of

5.4-magnitude soon after, the USGS said.

Around 20 percent of the world's most powerful earthquakes strike Japan, which

sits on the " Ring of Fire " surrounding the Pacific Ocean.

In 1995 a magnitude-7.2 quake in the port city of Kobe killed 6,400 people.

But high building standards, regular drills and a sophisticated tsunami warning

system mean that casualties are often minimal.

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