Apr 19, 2007 9:36 pm US/Pacific
(CBS 5 / AP) TOKYO A series of strong earthquakes rattled southwestern Japan on Friday morning, prompting the government to warn of a possible tsunami that ultimately never came.
There were no immediate reports of major damage or injuries from the quakes.
The Meteorological Agency issued a tsunami advisory for southwestern Japan after an earthquake with preliminary magnitude 6.7 struck.
The notice covered islands around Miyakojima, part of the Ryukyu island chain that stretches southwest toward Taiwan.
A tsunami advisory is used when waves are forecast to be no more than 18 inches tall, agency official Yuji Nishimae said. The agency issues a warning when the waves are forecast to be 3 to 6 feet high, and warns of a large tsunami when higher waves are expected, he added.
The agency lifted its advisory about an hour after issuing it. No tsunami was detected, agency official Kana Akiyama said.
The 6.7-magnitude quake came shortly after a tremor with a preliminary 6.2 magnitude quake struck the same area. A third quake, also with a preliminary 6.2 magnitude, followed later in the morning.
People living on the island were warned to stay away from the coast as a precaution.
"I could feel a little bit of shaking, but it wasn't strong enough to rattle cups on desktops and the like," local policeman Takumi Higa said.
Japan is one of the world's most earthquake-prone countries because it sits atop four tectonic plates. A magnitude 5.5 earthquake jolted northern Japan early Thursday, but there were no reports of injuries or damage.
Miyakojima, part of the state of Okinawa, is about 1,130 miles southwest of Tokyo.
Seismic hazard map of the strongest earthquake of 6.1 magnitude. According to the USGS numerous earthquakes ranging from magnitudes 5.1 to 6.1 have been reported off the western coast of Japan, prompting tsunami warnings to be issued. The warnings were lifted a short time later.

The first quake, a 6.0 magnitude, was reported at 9:26 a.m. local time (00:26 UTC), 165 km (105 miles) north, north east of Ishigaki-jima, in the Ryukyu Islands in Japan.

The second quake of 5.6 magnitude struck just five minutes after the first and a 6.1 magnitude quake struck just over an hour later, followed by a magnitude 5.9 about 15 minutes later.

Japan's weather agency says the first and last quakes were actually 6.7 magnitude.

Three smaller quakes ranging from 5.1 to 5.3 magnitudes shortly followed.

The tsunami warnings were issued only after Japan's weather agency said that an 18-inch (46cm) wave could be a possibility.

There are no reports of damage, injuries, deaths or tsunamis.