Amid rumors of a 2nd nuclear test, now we find this:

http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/ustrb2.php#details

Magnitude 5.8 (Moderate)
Date-Time Tuesday, October 10, 2006 at 23:58:07 (UTC)
= Coordinated Universal Time
Wednesday, October 11, 2006 at 9:58:07 AM
= local time at epicenter Time of Earthquake in other Time Zones
 
Location 37.252°N, 142.722°E
Depth 30.1 km (18.7 miles) set by location program
Region OFF THE EAST COAST OF HONSHU, JAPAN
Distances 165 km (100 miles) E of Iwaki, Honshu, Japan
195 km (120 miles) SE of Sendai, Honshu, Japan
205 km (130 miles) ESE of Fukushima, Honshu, Japan
320 km (200 miles) NE of TOKYO, Japan
 
Location Uncertainty horizontal +/- 7.7 km (4.8 miles); depth fixed by location program
Parameters Nst=170, Nph=170, Dmin=410 km, Rmss=1.03 sec, Gp=108°,
M-type=moment magnitude (Mw), Version=7  
Source USGS NEIC (WDCS-D)
 
Event ID ustrb2

Quake tremors put Japan on edge

A jittery Japan has apparently mistaken earthquake activity off its own coast for a tremor indicating a second nuclear test in North Korea.

Japan's NHK news service first reported the tremor Wednesday, quoting a Japanese government source saying that it appeared to indicate North Korea had undertaken another nuclear test, just two days after conducting a test that sparked international condemnation.

Japan's meteorological agency reported a magnitude-6.0 earthquake shook northern Japan, according to a report from The Associated Press. Agency spokesman Yukuhiro Watanabe said that quake was being considered separately from reports of new tremors in North Korea.

But South Korea's Yonhap news agency almost immediately quoted that country's officials saying they had registered no seismic activity in North Korea, and the U.S. Geological Survey quickly followed suit.

Japan's Kyodo News reported that Prime Minister Shinzo Abe said he had no information to confirm a second nuclear test.

Then came news from both the Japanese Meteorological Society and USGS of a moderate earthquake -- 5.8 magnitude, according to USGS -- shortly before 10 a.m. Wednesday (8 p.m. ET Tuesday) off the east coast of Japan's Honshu island.

"Apparently the government of Japan is saying that the tremor they registered was from mild earthquake activity in Japan and not North Korea," a Pentagon official told CNN.