The 1707 H?ei earthquake causes more than 5,000 deaths in Japan.

The 1707 H?ei earthquake was one of the most powerful and destructive earthquakes in Japanese history, striking southern Japan on 28 October 1707 during the Edo period. Estimated to have had a magnitude of approximately 8.6 to 8.7, the earthquake occurred along the Nankai Trough, a major submarine fault system where the Philippine Sea Plate is being forced beneath the Eurasian margin. The earthquake ruptured an exceptionally long section of this plate boundary, affecting a vast area stretching from the Kii Peninsula to Shikoku and Kyushu. Violent shaking was experienced across much of central and southwestern Japan, destroying buildings, damaging roads and triggering widespread landslides. The earthquake was particularly significant because it appears to have involved the simultaneous rupture of several segments of the Nankai Trough, which have also produced major earthquakes individually throughout Japanese history.

The earthquake generated a devastating tsunami that struck Japan’s Pacific coastline, particularly the coastal regions of Shikoku, the Kii Peninsula and the T?kai region. In some locations, tsunami waves reached heights exceeding 20 metres, sweeping away entire settlements, destroying fishing vessels and flooding agricultural land with seawater. The combined effects of the earthquake and tsunami caused thousands of deaths, with historical estimates commonly placing the death toll at more than 5,000, although the precise number remains uncertain. The disaster also caused extensive economic damage, destroying homes, warehouses, temples and important infrastructure. Coastal communities suffered particularly severe losses as farmland became contaminated with salt, fishing industries were disrupted and survivors struggled to rebuild their livelihoods. The enormous geographical extent of the destruction made the H?ei earthquake one of the most significant natural disasters experienced by Japan during the Edo period.

One of the most remarkable consequences associated with the H?ei earthquake was the eruption of Mount Fuji on 16 December 1707, just 49 days after the earthquake. This eruption, known as the H?ei eruption, was Mount Fuji’s last recorded eruption and sent enormous quantities of volcanic ash and rock into the atmosphere, with ash falling as far away as Edo, modern-day Tokyo. Scientists believe that the immense stresses generated by the earthquake may have disturbed the magma system beneath Mount Fuji, helping to trigger the eruption, although the precise relationship remains a subject of scientific investigation. The 1707 H?ei earthquake remained Japan’s largest known historical earthquake until the magnitude 9.0 T?hoku earthquake in 2011. Today, the H?ei disaster is an important reference point for Japanese earthquake research and tsunami preparedness, particularly because the Nankai Trough remains capable of producing similarly devastating earthquakes in the future.