Japan earthquake sparks tsunami scare

A 7.3 magnitude quake has struck off Japan’s eastern coast, triggering a small tsunami and sparking evacuations.

A one-meter wave hit Ishinomaki in Miyagi Prefecture and many people heeded calls to move to higher ground before all alerts were later lifted.

The quake epicenter was about 245km (150 miles) south-east of Kamiashi at a depth of about 36km, the US Geological Survey said, according to BBC.

Miyagi was hit by a devastating earthquake and tsunami in March 2011.

The US-based Pacific Tsunami Warning Center had said there was no threat to the wider Pacific Ocean but had warned a local tsunami could be destructive for local coastlines.

There have been no reports of deaths or injuries, and all tsunami warnings were cancelled at 19:20 local time (10:20 GMT), broadcaster NHK said.

Warnings of the tsunami height had varied between 50cm and 2m.

The BBC’s Rupert Wingfield Hayes in Tokyo says any such height would represent a far lower risk of devastation than the tsunami of up to 11 meters that struck in 2011 but that, since then, the country has clearly become jittery about any shaking of the earth.

The tsunami warnings had extended from the top of the main island of Honshu down towards Tokyo and evacuations were ordered from some of the affected areas.

With Japan’s early warning system, NHK was able to break off its regular programming and issue an alert about the earthquake shortly before it struck.

A presenter on state broadcaster NHK then told viewers: “Remember last year’s quake and tsunami. Call on your neighbors and flee to higher ground now!”

Friday’s earthquake has been a showcase for Japan’s early warning system, first tested in 2004. Many on the ground say they received warning alerts on their mobile phones tens of seconds before the earthquake hit.

Japan’s network of seismometers detects the arrival of one of two types of quake waves – the faster-moving but much less damaging “P waves”. That surely allows precious seconds to seek shelter but in reality it is only detecting a quake, not predicting one.

The science behind longer-term predictions – hours, days or weeks in advance – is the subject of intense research. This ranges from using satellites to detect tiny deformations of the Earth’s surface through purely mathematical approaches to harnessing animals’ purported ability to sense coming quakes. But scientists are still some way from making reliable predictions – and avoiding the damaging risk of false alarms.

Prime Minister Yoshihiko Noda cancelled campaigning for the 16 December election to return to his office.

Jamie El-Banna, founder of It’s Not Just Mud – a volunteer disaster relief organisation – said he joined the evacuation in Ishinomaki.

He told the BBC: “We live less than a kilometre from the water so we went calmly as far back from the water as possible, which is what the advice is if you can’t get to higher ground. Everyone evacuated in a calm, orderly way.”

The USGS reported three aftershocks in the same area, of 6.2, 5.5 and 4.7 magnitudes.

The 9.0 magnitude quake that struck on 11 March 2011 caused a devastating tsunami and left more than 15,000 people dead, with more than 3,200 missing.

That quake triggered a meltdown of fuel rods at the Fukushima nuclear plant, causing radiation leaks and mass evacuations.

R.S