Houses (botttom R) are seen near by a landslide caused by an earthquake in Kurihara, Miyagi prefecture, on June 14, 2008. A powerful earthquake struck northern Japan killing three people, injuring more than 100. Photo courtesy AFP.Quake warning system in action in Japan
The world’s first earthquake early warning system was used in Japan on Saturday, giving residents a few seconds to prepare for aftershocks that followed a strong quake. The warning system, launched in October, kicked in for the quake in northern Japan, which registered 7.2 on the Richter scale and struck at 8:43 am (2343 GMT). The Japan Meteorological Agency said the first warning was issued four seconds after seismic waves were first detected. But in Tokyo, some 500 kilometres (300 miles) from the epicentre, an alert was flashed on public broadcaster NHK moments before residents of the capital felt a tremor. The agency issued warnings in time for aftershocks, including a 5.6-magnitude quake. A small window alerting residents opens on the NHK screen each time the meteorological agency issues a warning. Japan, where 20 percent of the world’s major quakes take place, developed the system largely to provide advance notice to nuclear power plants, railways and other infrastructure that can automatically shut down. The agency has said advance warning is easier to issue further from the epicentre.
  

by Staff Writers
Tokyo (AFP) June 15, 2008

A powerful earthquake in Japan struck at a previously unknown faultline, raising new alarm that the dreaded “Big One” could hit anywhere in the country experts said Sunday.
The 7.2-magnitude quake Saturday was the most powerful to strike inland Japan in eight years, killing at least nine people and triggering massive landslides.
“Seismically speaking, major earthquakes can strike anywhere and anytime in Japan,” said Ryohei Morimoto, a seismologist and honorary professor at the University of Tokyo.
“Therefore, it would be no surprise if another earthquake matching the one on Saturday occurs in any part of the country in the near future,” Morimoto said.

The meteorological agency said it had predicted an offshore jolt could strike near the region, in the north of Japan’s main island of Honshu, but admitted it did not consider the inland area at major risk.

“We had not been aware of faults in the area where the earthquake occurred this time,” Takashi Yokota, a senior official of the agency’s earthquake and tsunami monitoring bureau, told a news conference.

Experts said that the quake, whose focus was located a shallow eight kilometres (five miles) deep, was triggered due to the build-up of pressure where the Pacific Plate meets the Japanese archipelago.

Japan, which lies at the crossing of four tectonic plates, experiences 20 percent of the world’s powerful earthquakes and is constantly striving to protect against major tremors.

Japan has started a world-first early warning system for earthquakes by monitoring seismic waves. The system kicked in on Saturday, offering alerts several seconds in advance.

But much about earthquakes have yet to be understood, experts said.

“A lot of questions have not been answered,” said Yoshimasu Kuroda, honorary professor of geology and geochemistry at Shinshu University in Nagano, central Japan.

“We have to face this reality,” Kuroda said. “All we can do is to collect as much information as possible from the latest one and analyse it for better understanding of the Earth.”

Despite the massive strength of the tremor, damage to facilities and casualties were limited as it hit rural areas. About 9.7 million people live in the rice-growing region, accounting for seven percent of Japan’s population.

By contrast, a government study in 2006 warned that a 7.3 Richter-scale earthquake in Tokyo would kill 4,700 people and damage 440,000 buildings.

The last giant tremor in Tokyo was the Great Kanto Earthquake of 1923, which left 142,807 people dead.

The 1995 Kobe earthquake, which measured 7.3 on the Richter scale, killed 6,434 people. It caused 200 billion dollars in economic damage, considered the highest ever to a single country from a disaster.

(The same AFP report also appears as “Japan threatened by ‘Big One'”, Japan Times June 21, 2008)

 

 

 

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