induce changes in either strain throughout the eastern Nagano Akita

After an earthquake off the northeast and east by another aftershock, magnitude (M) 5 ~ earthquakes have occurred in a series of six classes.
At around 3:00 am on 59, 12 and M6.7 earthquake in the northern part of Nagano Prefecture earthquake, seismic intensity 6 shaking observed in the prefecture Sakaemura. M5 occurred at around 5:00 42 4:00 31 at around the same class as aftershocks were recorded at intensity 6 lower Sakaemura both. 47 minutes around 4:00 also said that the epicenter was also an M6.4 earthquake off the coast of Akita.
Yokoyama Hirobumi tsunami monitoring section chief of the Meteorological Agency, the relationship between earthquake off the northeast while unknown, so far as no cases occurred frequently in the past "is a wide ranging impact of Kina Hiroshi deformation. Happening almost is likely to induce an earthquake possible in general, "explained.
Nagoya University Prof. K. Yamaoka spring (seismology), even earthquakes in northern Nagano Prefecture, Akita Prefecture earthquake off "potential impact of earthquakes induced by both the earthquake off the northeast can not be denied, must be considered There will. are very similar to the strain concentration zone occurs in a relatively unlikely to be coincidental, "he said.
Earthquake off the coast of Akita Prefecture, Japan Sea Earthquake tsunami in 1983 accompanied by 10 meters near the Sea of ​​Japan (M7.7) occurred in the vicinity and found the source area. According to Prof. Yamaoka, and is generally earthquake-induced (a) more power to slide against the fault plane (2) reduce the friction force fault - it refers to action. After an earthquake off the coast of the Tohoku Geographical Survey Institute of GPS (Global Positioning System) was observed in the crustal movement "(the earthquake) and gave the change in strain across the East no doubt," explained.
Meanwhile, the weather bureau after an earthquake off the northeast announced EEW 12 times 9:00 am, 12 cases have been on the wrong areas and caused large.Shinetsu region after the earthquake and the earthquake, and that the aftershocks occurred about the same each time, it has failed many seismic earthquake off the northeast of the epicenter can not know exactly. Mr. Yokoyama said, "some may fail to properly announce early warning, evacuation want to take just in case" and has called for. 


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東北沖大地震の発生後、東日本では余震とは別に、マグニチュード（Ｍ）５～６クラスの地震が相次いで発生している。

　１２日午前３時５９分ごろ、長野県北部を震源とするＭ６．７の地震があり、同県栄村で震度６強の揺れを観測。Ｍ５クラスの余震が同４時３１分ごろと同５時４２分ごろに発生し、いずれも栄村で震度６弱を記録した。また同４時４７分ごろには、秋田県沖を震源とするＭ６．４の地震も発生した。

　気象庁の横山博文・地震津波監視課長は、東北沖大地震との関連は不明としながらも、ここまで多発した例は過去にないとして「大きな地殻変動の影響が広域に及んでいる。もう少しで起きそうな地震を誘発することは一般的にありうる」と説明する。

　山岡耕春・名古屋大教授（地震学）も、長野県北部の地震と、秋田県沖の地震について「両地震が東北沖大地震の影響で誘発された可能性は否定できず、検討する必要があるだろう。比較的良く似たひずみ集中帯で発生しており、偶然とは思えない」と話す。

　秋田県沖の地震は、日本海側に１０メートル近い津波を伴った１９８３年の日本海中部地震（Ｍ７．７）の震源域付近で起きたとみられる。　山岡教授によると、一般的に地震の誘発とは（１）断層面に対して滑らせる力が増える（２）断層面の摩擦力を減らす－－という作用を指す。東北沖大地震後、国土地理院がＧＰＳ（全地球測位システム）で観測した地殻変動から「（同地震が）東日本全体にひずみの変化を与えたのは間違いない」と説明する。

　一方、気象庁は東北沖大地震発生後、１２日午前９時までに１２回の緊急地震速報を発表したが、規模や発生地域を誤るケースが相次いでいる。同地震や信越地方の地震発生後、それぞれの余震がほぼ同時刻に発生したことや、東北沖大地震で多くの地震計が故障したことで、震源を正確に把握できないためという。横山課長は「緊急地震速報を適切に発表できない恐れもあるが、念のため避難行動を取ってほしい」と呼びかけている。