Home Geography Seismic Japan
Genroku, 1703 (Genroku 16)/11/23
The M7.9–8.2 Genroku earthquake occurred at about 2 a.m. on December 31, 1703, resulting in over ten thousand deaths. It was an ocean trough earthquake originating somewhere between Sagami Bay and the area off the southern shore of the Bōsō Peninsula. It was the same type as the Great Kantō Earthquake of 1923, one of the M8 class earthquakes whose origins are the ocean troughs caused by the Philippine Sea Plate subducting beneath the Eurasian Plate and the North American Plate. These earthquakes typically are damaging in and of themselves, and they usually generate tsunamis. In the case of the Genroku earthquake, tsunamis of between 2 and 10.5 meters in height struck the coast between Shimoda and Inuboesaki, washing approximately six hundred to their deaths near Kamakura. The total death toll from the seismic sea waves probably numbered in the thousands. Shaking could be felt as far away as the Kinki region, and the earthquake and tsunami destroyed over twenty-eight thousand structures. This earthquake caused uplift in the southern part of the Bōsō Peninsula by as much as 5.5 meters. Daimyō mansions on solid ground such as the Yamanote area suffered relatively light damage, whereas alluvial areas of Shitamachi suffered severe damage. This earthquake prompted a change of era name from Genroku to Hōei.
Hoei, 1707 (Hoei 4)/10/4
The change of era names, however, did not mollify the cosmic forces. On October 28, 1707, nearly the entire Nankai Trough plate boundary ruptured at once. Until March 11, 2011, many specialists regarded the resulting M8.4 Hōei earthquake as the strongest seismic event to shake Japan. It caused at least five thousand deaths and possibly as many as fifteen thousand. It generated tsunamis from the Izu Peninsula to Kyushu, and the waves reached heights of five to eight meters in Shikoku. They washed away nearly eighteen thousand homes and destroyed some three thousand boats and ships. Uplift and subsidence were common throughout Shikoku. Tsuro and Murozu harbors in Murodozaki (Tosa) experienced about 1.8 meters of uplift, and a twenty-square-kilometer area near Kōchi sank by about 2 meters.
Sanjo(Echigo), 1828 (Bunsei 11)/11/12
At about 7 a.m. on a market day, December 18, 1828, the earth around Sanjō in Echigo (Niigata Prefecture) began to shake. The M6.9 inland, shallow-focus earthquake caused liquefaction (many buildings sank about one meter into the earth), landslides, and fissures in the earth from which water and sand flowed. The earthquake caused 1,443 deaths, collapsed 9,808 structures, and burned 1,204 more. The shaking began just after many merchants in the marketplace had started their fires to prepare food, and many fled without extinguishing them. Soon the whole town was ablaze, and the cries of trapped victims mingled with cries of those chanting the
Kyoto, 1830 (Bunsei 13/Tenpo1)/7/2
At roughly 4 p.m. on August 19, 1830, an inland earthquake of approximately M6.5 shook Kyoto. The epicenter was slightly to the northwest of the city. Kyoto's death toll in 1830 was between two and three hundred. Heavy shaking was limited to the city itself, although some outlying areas experienced minor damage and the earthquake was felt in nearby cities such as Osaka. Destruction of storehouses was widespread, but destruction of houses was relatively modest. Nijō Castle suffered serious damage, and liquefaction was widespread throughout the city. As was usual by this time, there were reports of light flashes in the sky and bursts of light issuing forth from the earth.
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