Overview
Among the oldest Japanese entries in the significant-earthquake catalogue, the shock of 12 May 701 carries a magnitude of 7.0 and a location in what is now Kyoto Prefecture, at 35.7 N, 135.4 E. The position lies on the Sea of Japan side of central Honshu, a belt of active crustal faulting well inland of the Nankai Trough, where ruptures break the upper plate rather than the subduction interface. No focal depth, intensity rating, or casualty figure accompanies the entry. Magnitudes for events of this antiquity are estimates back-calculated from the geographic spread of reported damage rather than measurements, and their uncertainty is correspondingly wide. The date falls in the first year of the Taiho era, at the beginning of Japan's continuous written record.
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Energy Released
31.8 atomic bombs
About This Earthquake
701 Japan, Kyoto Prefecture: M7.0 earthquake, shallow crustal focus. No fatalities recorded. Pacific Ring of Fire subduction zone.
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Frequently Asked Questions
The largest earthquake ever recorded was the 1960 Valdivia earthquake in Chile, at magnitude 9.5. It generated a tsunami that traveled across the Pacific Ocean and caused damage as far away as Hawaii and Japan. The earthquake killed approximately 1,655 people and left 2 million homeless.
The deadliest earthquake in recorded history was the 1556 Shaanxi earthquake in China, estimated at magnitude 8.0-8.3, which killed approximately 830,000 people. Many casualties resulted from the collapse of yaodong (cave dwellings) carved into loess cliffs. The 2010 Haiti earthquake (M7.0, ~316,000 deaths) was the deadliest in modern times.
Pre-instrumental earthquake magnitudes are estimated from written accounts of damage, felt reports, geological evidence such as fault scarps and liquefaction features, and tsunami records. These methods provide approximate magnitudes with typical uncertainties of 0.3-0.5 magnitude units.
QuakeFYI's historical database covers earthquakes from approximately 2150 BC to the present, with over 5,700 significant events. Written records from ancient China, Greece, and the Middle East provide some of the earliest accounts. Instrumental recording began around 1900 with the first standardized seismographs.
An earthquake swarm is a sequence of many earthquakes occurring in a localized area over weeks to months without a clear mainshock. Unlike aftershock sequences where one large event is followed by smaller ones, swarms have no single dominant event. They are often associated with volcanic activity or fluid migration in the crust.