1200 years after the Tencho Earthquake 　 　Of the 39 damaging earthquakes that have occurred in and around Akita Prefecture since recorded history, including those with a magnitude (M) of 6 or less, the Tencho earthquake that occurred in 830 is the oldest. The earthquake was a shallow-type earthquake with a magnitude of 7.0 … Continue reading 1200 years after the Tencho Earthquake (1) Akita Castle →