A tsunami is a series of ocean waves generated by sudden displacements in the sea floor, landslides or volcanic activity. In the deep ocean, the tsunami wave may only be a few inches high. In 1868, a tsunami struck the coast from Hilo to South Cape, being most destructive at Keauhou, Puna and Honuʻapo; 180 houses were washed away and 62 lives were lost to the wave alone. Maximum wave heights were 65 feet, the highest observed on Hawaiʻi to date.
Other significant tsunami include, 1946 was generated by a magnitude 7.1 earthquake in the Aleutian Islands, This tsunami struck the Big Island of Hawaii on April 1st; on November 4, 1952 a tsunami was generated by a magnitude 8.2 earthquake on the Kamchatka Peninsula in the USSR; on March 9, 1957 a tsunami was generated by a magnitude 8.3 earthquake in the Aleutian Islands; the tsunami of May 23, 1960 was generated by a magnitude 8.3 earthquake in Chile; on November 29, 1975, an earthquake occurred off the coast of the Big Island of Hawaii; and an earthquake measured at 9.0 magnitude, the sixth biggest since 1900, struck Japan on March 11, 2011.