[3] The 8.5 magnitude earthquake occurred at 19:32 (local time) on June 15, 1896, approximately 166 kilometres (103 mi) off the coast of Iwate Prefecture, Honshu.

[2] The unusual disparity between the magnitude of the earthquake and the subsequent tsunami may be due to a combination of factors:[2] Scientists believe the effect of subducted sediment beneath the accretionary wedge was responsible for a slow rupture velocity.

The effects of a 20° dipping fault along the top of the subducting plate was found to match both the observed seismic response and tsunami, but required a displacement of 10.4 m.[2] The displacement was reduced to a more reasonable value after the extra uplift caused by the deformation of sediments in the wedge and a shallower fault dip of 10° was considered.

[1] On the evening of June 15, 1896, communities along the Sanriku coast in northern Japan were celebrating a Shinto holiday and the return of soldiers from the First Sino-Japanese War.

[3] Nevertheless, the earthquake of 11 March 2011 caused a huge tsunami that resulted in thousands of deaths across the same region and the nuclear disaster at Fukushima.