Aftershock or not ?

February 17, 2015

Two quakes shake Tohoku; small tsunami hits coast

http://www.japantimes.co.jp/news/2015/02/17/national/tsunami-advisory-issued-6-9-magnitude-quake-hits-iwate/#.VOOP7S51Cos

JIJI, Reuters, AFP-JIJI, Staff Report

An earthquake measuring upper-5 on the Japanese seismic intensity scale of 7 shook Aomori Prefecture and other parts of the north on Tuesday afternoon, hours after another temblor triggered a small tsunami.

The second instance did not result in a tsunami alert.

The quake struck at 1:46 p.m. The Japan Meteorological Agency described it as magnitude 5.7, with an epicenter around 50 km off the coast of Iwate Prefecture and 50 km deep.

One of the hardest-hit districts was the town of Hashikami, where upper-5 was recorded. It registered as 5-weak in the village of Fudai in Iwate Prefecture.

There were no reported problems at nuclear plants in the area, Kyodo reported.

Earlier in the day, a small tsunami struck the coast of Iwate Prefecture, with a maximum surge of 20 cm recorded at one location.

The tsunami was triggered by a subsea quake with an estimated magnitude of 6.9. It struck on Tuesday morning about 210 km east of the city of Miyako and 10 km deep, the agency said.

Sirens sounded as residents sought higher ground. The largest tsunami waves were measured between 8:35 a.m. and 9:07 a.m. at a port in the city of Kuji, and a 10-cm surge was recorded in Miyako. A smaller tsunami reached the city of Kamaishi, the agency said.

Evacuation orders were issued for residents in coastal districts of Kuji and the town of Otsuchi, and evacuation advisories for the cities of Ofunato and Rikuzentakata as well as Kamaishi.

The Iwate Prefectural Government reported no damage from the waves.

The quake hit at 8:06 a.m. It measured 4 on the Japanese seismic intensity scale of 7 in Iwate and three other prefectures in Tohoku — Aomori, Akita and Miyagi.

The quake was believed to be an aftershock of the 9.0-magnitude earthquake that hit the Tohoku region on March 11, 2011, the meteorological agency said.

Tohoku Electric Power Co., which operates the Onagawa and Higashidori nuclear plants in nearby Miyagi and Aomori prefectures, said it saw no irregularities at the facilities after the quake.

All 48 of Japan’s workable nuclear reactors remain offline after the March 2011 earthquake and tsunami triggered the Fukushima No. 1 plant meltdown disaster.

A spokesman for Tokyo Electric Power Co., the operator of Fukushima No. 1 and Fukushima No. 2 nuclear plants, said there were no irregularities at the plants. The quake was felt only weakly in the area, he said.

Unlisted Japan Nuclear Fuel Ltd. also said there were no irregularities recorded at its nuclear fuel reprocessing facility or other plants in Aomori.

East Japan Railway Co. briefly halted Tohoku Shinkansen bullet trains between Furukawa Station in Miyagi and Shin-Aomori Station in Aomori amid a power failure.

The evacuation instructions and advisories were lifted at 10:20 a.m.

Large areas of the coastline covered by Tuesday’s warning were damaged by the 2011 quake and tsunami that killed more than 18,000 people and triggered a nuclear disaster.

Earthquakes are common in Japan, one of the world’s most seismically active areas. The nation accounts for about 20 percent of the world’s earthquakes of magnitude 6 or greater.

See also :

http://enenews.com/quake-magnitude-7-hits-northeast-japan-strongest-hit-country-2013-felt-along-entire-pacific-coastline-1000-km-followed-multiple-aftershocks-one-centered-japan-trench-official-event-related

Japanese coastal towns evacuated as earthquake hits Pacific

Tsunami warning issued by Japan Meteorological Agency as residents of Iwate prefecture are cleared from homes, though no damage or injuries reported

http://www.theguardian.com/world/2015/feb/17/japanese-towns-evacuated-earthquake-tsunami-warning

Evacuations were ordered for towns closest to the coast in Iwate prefecture in Japan early on Tuesday morning after a strong earthquake with a preliminary magnitude of 6.9 was recorded off the country’s coast.

The Japan Meteorological Agency issued a tsunami warning and Japanese broadcaster NHK warned residents a one metre-high wave was expected to hit the coast of Iwate. The quake was measured at a depth of about six miles and shook much of north-east Japan even being felt in Tokyo, 430 miles away.

There were no immediate reports of damage or injuries. The Pacific Tsunami Warning Center in Hawaii said there was no danger of a Pacific-wide tsunami.

NHK later said that small tsunamis of about 10 centimetres were recorded about 45 minutes after the quake hit and warned people to stay away from the shore.

Tohoku Electric Power Co and Tokyo Electric Power Co, both of which operate nearby nuclear plants, reported no irregularities at their facilities after the quake. Unlisted Japan Nuclear Fuel Ltd also said there were no irregularities recorded at its nuclear fuel reprocessing facility or other plants in Aomori.

All 48 of Japan’s nuclear reactors remain offline after a March 2011 earthquake and tsunami, which triggered the Fukushima nuclear disaster in north-east Japan.

6.7 Earthquake Jolts Northern Japan, Triggers Tsunami Warning

http://www.nbcnews.com/news/world/6-7-earthquake-jolts-northern-japan-triggers-tsunami-warning-n307196

TOKYO — A shallow 6.7-magnitude earthquake jolted northern Japan early Tuesday, triggering a tsunami warning and advisories cautioning people to stay away from the coast. The warning and advisories ended later Tuesday.

The quake on Tuesday struck off the coast of Iwate Prefecture, where authorities had issued a tsunami warning and expected 3-feet-high waves. The quake's epicenter was 50 miles north of Miyako and 330 miles north of Tokyo, at a depth of 14 miles, according to the U.S. Geological Survey.

No damages or injuries were reported.

Onagawa Nuclear Power Plant in Miyagi Prefecture said there haven't been any disruptions or damage from the quake and bullet trains were running on regular schedules, Japan's NHK television reported.

Japan's Meteorological Agency cast the quake as an aftershock of the 9.0 temblor that rocked Japan on March 11, 2011, killing at least 15,800 people and caused the meltdown of three reactors at the Fukushima Daiichi Nuclear Power Plant.

"Because the 3/11 earthquake had such a strong impact, and because it's an area where it was affected by the 3/11 Earthquake, we are describing this as an 'aftershock,'" said agency seismologist, Yasuhiro Yoshida.

Japan regularly experiences moderate size earthquakes in the area of the 2011 temblor several times a month, and JMA attributes most of them to the 2011 quake.

USGS wasn't characterizing Tuesday's quake as an aftershock, considering it a separate event.