The November 29, 1975 event near the Hawaii Island coast had magnitude 7.7, with a maximum Mercalli intensity of VIII, and caused a near-field tsunami reaching about 40 to 47 feet, resulting in two deaths and extensive property loss. The quake produced subsidence and ground cracking on the Big Island, and the tsunami propagated to distant shores, while shoreline changes included notable subsidence. The event is linked to the Hilina Slump source and to earlier and later seismic activity in the region.
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November 29, 2025 marks the 50th anniversary of the M7.7 earthquake that struck just offshore of the southern coast of Hawaii’s Big Island, generating a deadly tsunami.
quakefeed.substack.com80th Governor George R. Ariyoshi and President Gerald R. Ford declared Hawaii County a major disaster area due to an earthquake-tsunami which struck there at 4:48 a.m., Nov. 29, 1975. Within minutes, a tsunami with 40-foot waves followed the earthquake. Two people were killed and approximately $4.1 million in property damage occurred due to the […]
dod.hawaii.govA magnitude 7.7 (revised 2018) earthquake off the coast of the Island of Hawaii (the “Big Island”) on November 29, 1975, was felt throughout the island, as well as on Lanai, Molokai, and Oahu. The quake caused extensive ground cracking and subsidence; in one area, the coast permanently subsided over 11 feet. The quake triggered a near-field tsunami, with waves up to nearly 26 feet in the area of Halape; far-field tsunami waves were recorded in Alaska, California, Japan, and Samoa.
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