A:The largest documented tsunamion record occured in the Ryukyu Islands of Southern Japan in 1971, when a tsunami raised the normal sea level by 85 metres. The heights of tsunami are reported in vertical distances and reflect the amount of water level rise above normal sea level. In low-lying coastal area, such a vertical rise can extend inland many kilometres, causing flooding and widespread damage. The most deadly tsunami was probably the tsunami in 1703 that hit Aura, Japan, and was responsible for an estimated 100,000 deaths. Perhaps it is not surprising that thw record height was noted in Japan, because Japan's proximity to subduction zones causes that country to endure more tsunamis than any other place on Earth( followed by Chile and Hawaii).