Hawaii gets tsunamis, and it is one of the most tsunami-exposed places in the United States. Situated in the middle of the Pacific Ocean, surrounded by the tectonically active Ring of Fire, the islands face destructive tsunami events roughly every 11 years on average. Since records have been kept, nine major tsunamis have killed 293 people and caused over $625 million in damage (in 2022 dollars).
Where Hawaii’s Tsunamis Come From
Tsunamis reach Hawaii from two distinct sources. The more common and historically deadlier type originates thousands of miles away along the Pacific Rim, where massive earthquakes at subduction zones displace enormous volumes of water. These distant tsunamis (sometimes called teletsunamis) have come from Alaska, Chile, Japan, and other seismically active coastlines. Of the 293 tsunami deaths recorded in Hawaii, 245 were caused by distant sources.
The second type is local. Earthquakes and large-scale ground collapses along the south flank of Kīlauea volcano on the Big Island have generated tsunamis that strike nearby coastlines with almost no warning. The 1975 Kalapana earthquake produced waves with runup heights exceeding 15 meters (about 49 feet) on parts of the Big Island coast. Local tsunamis are less frequent but far more dangerous in terms of response time, since the waves can arrive within minutes rather than hours.
The Deadliest Events
The 1946 tsunami remains the worst in Hawaii’s modern history. A magnitude 8.6 earthquake in the Aleutian Islands sent waves racing across the Pacific, striking the Big Island town of Hilo with devastating force. Runup heights exceeded 15 meters in some locations. The disaster killed 159 people, most of them in Hilo, and became the catalyst for creating the Pacific Tsunami Warning Center.
In 1960, a magnitude 9.5 earthquake in Chile, the largest ever recorded, generated another catastrophic tsunami. Hilo was hit again, this time losing 61 residents. The Big Island has borne the overwhelming majority of Hawaii’s tsunami casualties: 86% of all fatalities occurred there, with 60% concentrated in Hilo alone. The city’s bay funnels incoming wave energy, amplifying heights and making it especially vulnerable.
The most recent significant event came in 2011, when the magnitude 9.1 Tohoku earthquake off Japan sent waves across the Pacific. Maximum wave heights in Hawaii reached about 3.6 meters (12 feet), causing roughly $8.7 million in damage across the counties of Honolulu, Maui, and Hawaii. Over 200 individual waves were recorded at varying heights. No one in Hawaii died, largely because of the warning system and organized evacuations.
How Much Warning You Get
The difference between a distant and local tsunami is measured in hours versus minutes. A tsunami originating in Alaska takes roughly five hours to reach Hawaii. One from Chile takes about 15 hours. One from Japan, as in 2011, takes even longer. That travel time gives authorities the window they need to issue warnings and evacuate coastal areas.
A local tsunami from a Kīlauea flank collapse or a nearby undersea landslide could arrive in minutes. There may be no time for sirens or official alerts. That’s why the guidance for local events is simple: if you feel shaking strong enough to knock you down or make it hard to stand, move to higher ground immediately without waiting for any official notification.
The Warning System
Hawaii uses a tiered alert system for distant tsunamis. At the lowest level, a Tsunami Information Statement means minor waves at most, with no action needed. A Tsunami Watch means the danger level isn’t yet known, and you should stay alert. A Tsunami Advisory means strong currents are likely and you should stay away from the shore. The highest level, a Tsunami Warning, means an inundating wave is possible and full evacuation is recommended.
When a warning is issued, Civil Defense sirens sound at specific intervals: three hours, two hours, one hour, and 30 minutes before the estimated arrival of the first wave. Alerts also go out through the Emergency Broadcast System on radio and television. One important detail: the sirens are never used to signal an all-clear. You’ll need to get that information from broadcast media or official channels.
What to Do in a Tsunami Zone
Every Hawaiian island has mapped tsunami evacuation zones, and if you’re visiting or living near the coast, it’s worth knowing whether your location falls inside one. The evacuation zone represents the minimum safe distance from shore, not a guaranteed boundary. Officials recommend moving well inland of the marked zone when a warning is issued.
If you can’t get inland quickly, vertical evacuation is an option. Reinforced concrete or structural steel buildings of six or more stories offer protection above the third floor. Buildings of ten or more stories provide increased safety on the fourth floor and above. You should also stay at least 100 feet from any inland waterways or marinas connected to the ocean, since wave surges can push far up connected channels.
Natural warning signs matter, especially for local tsunamis that arrive before sirens can sound. The ocean may suddenly drain away from the shore, exposing the seafloor like an extreme low tide. You might see a fast-rising flood or a visible wall of water. A deep, unusual roar from the ocean is another signal. Any of these means a wave could be seconds to minutes away, and the only correct response is to get to high ground as fast as possible.
Which Islands Face the Greatest Risk
The Big Island (Hawaiʻi Island) has historically absorbed the worst damage. Its position as the closest major island to many Pacific earthquake sources, combined with the bay geometry at Hilo, makes it uniquely vulnerable. But no island is immune. The 2011 tsunami caused damage across Honolulu, Maui, and Hawaii counties. Geological research on Maui has uncovered evidence of prehistoric tsunamis that predates written records, suggesting the threat extends further back and more broadly than the modern record alone shows.
Coastal development across all the islands means more people and property sit in potential inundation zones today than during the mid-20th century disasters. The warning systems are dramatically better than in 1946, when no organized alert network existed, but the fundamental exposure remains. Hawaii sits in the crosshairs of a geologically restless ocean, and tsunamis are a permanent part of life there.