Strong Quake Hits Northern Japan

At Least 60 Injured; 4-Inch Tidal Surge Hits Northeast Coast

(CBS/AP) 
The quake struck at around 11:46 a.m. (02:46 GMT) and was centered 12.4 miles below the ocean floor about 50 miles off the coast of Miyagi, the Meteorological Agency said. Two 4-inch tsunami waves hit the nearby coast shortly after noon, but officials expected little damage from the waves.

"Typically we find that the big tsunamis, the ones that cause considerable wave heights and travel large distances across the ocean are caused by the earthquakes of perhaps mid-7s or larger," Mike Blanpied of the U.S. Geological Survey told Early Show co-anchor Julie Chen. "Especially when earthquakes get up to the 8 or 8.5 or 9 size, then a considerable amount of the water can be displaced from the sea floor motion and cause large waves to travel out."

The quake was followed by at least four aftershocks, and agency official Yasuo Sekita warned area residents of possible aftershocks of similar strength.

"Please use caution the next few days at least, and beware of danger especially in areas where soil is loosened by rainfalls," he said.

The area is one of Japan's most earthquake-prone regions. Several powerful quakes have struck nearby in the past few decades, and the Education and Science Ministry earlier this year estimated it had a 99 percent chance of suffering a magnitude 7.5 quake in the next 30 years.

In 1995, a magnitude 7.3 quake in the western port city of Kobe killed 6,400 people. The depth and offshore location of Tuesday's quake helped limit the damage that might have occurred had it been centered under a city.

Authorities in Miyagi were still assessing damage.

The quake did not effect a nuclear power plant in neighboring Fukushima prefecture, the National Police Agency said.

Another plant in Onagawa in Miyagi shut down automatically and was being checked for damage, news reports said.

A falling stone lantern broke a 72-year-old man's leg, and two women were hurt when hot oil spilled on them in a supermarket, said Fukushima police spokesman Ichiro Oizumi.

Falling rocks injured a 7-year-old child in the town of Zao, said local official Mitsuharu Shishido.

Japan sits at the juncture of four tectonic plates, or moving slabs of the earth's outer crust, and is one of the world's most quake-prone countries. A magnitude 6.0 quake shook the Tokyo area on July 23, injuring more than two dozen people and suspending flights and trains for hours.

Earlier Tuesday, a 4.9-magnitude earthquake shook Japan's northern island of Hokkaido but did not trigger a tsunami.