貞じょう観がん地じ震しんじ字FuriganaMeanings1nounJōgan earthquake; Sanriku earthquake of 869 CEhistorical termHistorical term for a major earthquake that struck the Sanriku coast in 869 CE during the Jōgan era.貞じょう観がん地じ震しんは869年ねんに三さん陸りく沖おきで発はっ生せいした巨きょ大だい地じ震しんである。The Jōgan earthquake was a massive earthquake that occurred off the Sanriku coast in 869.