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Tsunamis are rare but dangerous natural disasters that can cause devastating damage to Hawaii’s coastal communities. If you’re wondering when Hawaii last experienced one of these exceptionally powerful waves, here is a quick answer: the last damaging tsunami to impact Hawaii occurred on October 15, 2006, generated by an earthquake in the Kuril Islands.

In this comprehensive article, we will provide a detailed overview of Hawaii’s history with tsunamis. We will discuss the causes of tsunamis that threaten the Hawaiian islands, describe past destructive tsunami events, and examine the most recent 2006 tsunami including the damage incurred.

We will also outline Hawaii’s current tsunami monitoring and warning system as well as tips for staying safe when a tsunami watch or warning has been issued.

What Causes Tsunamis that Threaten Hawaii

Seismic Activity and Underwater Landslides

The primary cause of tsunamis that impact Hawaii are underwater earthquakes and landslides. Hawaii’s location along the seismically active “Ring of Fire” in the Pacific Ocean puts it at risk from tsunamis generated by earthquakes and volcanic eruptions thousands of miles away.

For example, the devastating 1946 Aleutian Islands tsunami and the 1960 Chilean tsunami caused major damage across Hawaii.

Large earthquakes near Hawaii can also generate local tsunamis, like the 1975 Kalapana earthquake which caused a 38-foot tsunami on the Big Island. Underwater landslides along Hawaii’s steep slopes and along the islands’ flanks can also displace massive amounts of water and trigger destructive regional tsunamis.

Hawaii’s Location in the Pacific Ocean

In addition to seismic hazards, Hawaii’s mid-Pacific location makes it vulnerable to tsunamis originating from around the entire Pacific Basin. Waves generated by seismic activity and landslides off the coasts of Alaska, Russia, Japan, and South America take only a few hours to traverse the ocean and reach Hawaii.

Hawaii serves as a strategic tsunami monitoring location for NOAA’s Tsunami Warning Centers, which can provide advanced warning to Hawaii and other Pacific islands if a distant tsunami is detected. However, locally-generated tsunamis may provide little or no advance warning.

Developing robust warning systems, education campaigns, and evacuation protocols are key to enhancing Hawaii’s tsunami preparedness.

History of Destructive Tsunamis in Hawaii

1946 Aleutian Islands Earthquake Tsunami

On April 1, 1946, a magnitude 8.6 earthquake in the Aleutian Islands of Alaska generated a devastating tsunami that hit Hawaii. According to the National Weather Service, this was one of Hawaii’s most destructive tsunamis on record.

The waves reached up to 55 feet high and killed a staggering 159 people. In Hilo alone, 96 people perished as the tsunami waves obliterated the waterfront. Buildings, homes, and other infrastructure were severely damaged or completely washed away.

1957 Andreanof Islands Earthquake Tsunami

Just over a decade later on March 9, 1957, Hawaii was again impacted by tsunami waves stemming from an 8.6 magnitude quake in the Andreanof Islands of Alaska. According to the UH Sea Grant Program, these waves reached up to 32 feet high in certain areas.

In comparison to the 1946 event, the death toll was significantly lower at just 5 people. However, the tsunami still inflicted substantial damage, especially on Kauai which endured waves up to 55 feet in height.

1960 Chile Earthquake Tsunami

On May 23, 1960, the largest ever recorded earthquake with a staggering 9.5 magnitude rocked Chile. Thisevent unleashed a Pacific-wide tsunami, with waves battering Hawaii the next day. According to research by Gerard Fryer, these waves reached up to 35 feet tall in Hilo.

Thankfully, the death toll was minor and much lower than the prior tsunamis. However, 1961 Chile Earthquake Tsunami still caused considerable damage, with over $5 million in losses.

1964 Alaska Earthquake Tsunami

The last truly destructive tsunami to impact Hawaii occurred on March 28, 1964. This was triggered by the enormously powerful 9.2 magnitude Great Alaska Earthquake, the second biggest quake ever recorded. The waves arrived in Hawaii about 5 hours later, reaching up to 32 feet in height.

While less deadly than the 1946 event, the tsunami still took the lives of 14 people according to Hawaii disaster agency records. It also inflicted heavy damage across Oahu and Kauai in particular.

The Most Recent Damaging Tsunami – October 2006

The Triggering Kuril Islands Earthquake

On October 15, 2006, a magnitude 8.3 earthquake struck off the coast of the Kuril Islands in Russia. This powerful quake triggered tsunami waves that raced across the Pacific Ocean at up to 500 miles per hour, heading directly for Hawaii some 4,600 miles away.

According to the National Oceanic and Atmospheric Administration (NOAA), the triggering earthquake occurred at 11:14 PM Hawaii Standard Time and was one of the largest earthquakes worldwide that year.

Seismic activity and shakes were felt as far away as Alaska and along the western coasts of Canada and the mainland US.

Extent of Damage in Hawaii

Approximately seven and a half hours after the initial earthquake, waves as high as 16 feet began striking Hawaii. Impacts varied across the islands, but especially hard-hit areas included Hilo on the Island of Hawaiʻi and Hanalei Bay on Kauai.

According to Hawaii’s Department of Land and Natural Resources (DLNR), over $20 million in damage was recorded across state facilities, with clean-up efforts lasting for months. DLNR Chief Engineer Carty Chang stated that 110 different state sites were impacted, including harbors, airports, parks beaches, and historical landmarks.

Private buildings, homes, and businesses also sustained damage, as well as losses to the tourism industry. The tsunami put a particular strain on the economy of Western Kauai as popular tourist destinations were shut down for repairs.

Other Impacts in the Pacific

Beyond Hawaii, the October 2006 tsunami caused additional damage and loss of life across a vast area of the Pacific Ocean. Impacts were recorded from Alaska and down the western coasts of Canada, the US and Mexico.

Across the Pacific, several deaths occurred in Japan while damages were seen in Russia’s Kuril Islands and South Korea.

Ocean-wide, nearly $75 million of damage was recorded according to the National Geophysical Data Center (NGDC). Close to $26 million occurred in Hawaii alone, making it one of the costliest tsunami events in recent history for the state.

Hawaii’s Tsunami Monitoring and Warning System

Hawaii has an advanced tsunami monitoring and warning system in place to detect tsunamis and warn residents to evacuate. This system includes a network of sea level sensors, tide gauges, GPS stations, and seismic stations positioned along Hawaii’s coasts and across the Pacific Ocean.

According to the National Weather Service Honolulu Forecast Office, Hawaii’s tsunami warning system is composed of three main parts:

  • Detection – A network of seismic sensors and ocean buoys detect earthquakes and measure changes in sea level.
  • Warning Communication – Agencies issue tsunami warnings via TV, radio, phones, sirens, and social media.
  • Public Education – Community preparedness programs teach locals how to evacuate during a tsunami warning.

In total, Hawaii’s warning system leverages over 85 tidal gauges, 45 deep ocean buoys, and 175 seismic stations to monitor for tsunami threats across the Pacific basin 24/7. Advanced computer modeling helps scientists predict tsunami arrival times and heights.

Warning System Management

The tsunami warning system in Hawaii involves coordination between multiple federal, state, and county agencies such as:

  • Pacific Tsunami Warning Center (PTWC)
  • National Weather Service (NWS)
  • Hawaii Emergency Management Agency
  • County Civil Defense Agencies

These agencies monitor data streams, forecast tsunami impacts through modeling, disseminate warnings, trigger warning sirens if needed, and coordinate emergency response and evacuation procedures.

Recent System Improvements

After the devastating 2011 Japan earthquake and tsunami, Hawaii invested $50 million to enhance detection and warning capabilities. Upgrades included:

  • New tidal gauges and deep ocean buoys
  • Expanded seismic monitoring network
  • Enhanced software for real-time data analysis
  • Improved communication systems

Thanks to constant system testing and community education programs, Hawaii residents understand that when tsunami sirens sound, they should immediately evacuate to higher ground. This preparedness and early warning capability saves lives.

Staying Safe When a Tsunami Threatens

Understand Tsunami Warnings vs Watches

Knowing the difference between a tsunami warning and a tsunami watch is crucial for understanding the level of danger and determining the appropriate safety actions to take. According to the National Weather Service, a tsunami warning means a tsunami with significant inundation is imminent or expected.

Warnings indicate that widespread dangerous coastal flooding is possible and may continue for several hours after arrival of the initial wave. A tsunami watch means a tsunami was or may have been generated, but is at least two hours travel time to the area in watch status.

Watches indicate that dangerous coastal flooding is possible.

When a tsunami warning is issued, full evacuation of the threatened area is recommended. When a watch is issued, prepare to take action if a warning is later issued. Do not return to evacuated areas until authorities indicate it is safe to do so.

Paying attention to these alerts and understanding the terminology can save lives in a tsunami scenario.

Follow Evacuation Instructions Quickly

If you feel an earthquake that lasts 20 seconds or more when you are in a coastal area, immediately evacuate to high ground or move inland. Do not wait for an official warning. Some tsunamis can arrive within minutes. Authorities may not have time to issue an official warning.

And don’t expect the wave to look like a towering, curling wave depicted in movies. Often the first wave is a rapidly rising flood that can catch people by surprise if they are expecting a giant wave crest.

Carefully follow evacuation instructions from authorities, which are often informed by sophisticated computer models that predict tsunami arrival times and heights.

Plan evacuation routes in advance that lead to areas 100 feet or more above sea level, or at least one mile inland. If you can’t get this high or far, evacuate to the highest floor of a reinforced concrete hotel or municipal building.

Once there, be prepared to stay for at least 12 hours or until authorities indicate it is safe to return.

Prepare an Emergency Supply Kit

It’s wise for those in tsunami-prone areas to assemble an emergency supply kit that is ready to grab and go. Recommended items include:

  • Bottled water (1 gallon per person per day)
  • Nonperishable food
  • Battery-powered radio
  • Flashlights
  • Extra batteries
  • Whistle
  • Dust mask
  • Plastic sheeting
  • Duct tape
  • Moist towelettes
  • Garbage bags
  • Personal hygiene items
  • Cell phone charger

Also be sure to bring essential medications, cash, sturdy shoes, a map, gloves, waterproof matches, and any specialized items you need for yourself, family members, or pets. Having these basic supplies gathered in advance will allow you to evacuate more quickly and safely.


In conclusion, the last damaging tsunami to strike Hawaii occurred on October 15, 2006. Generated by a magnitude 8.3 earthquake in the Kuril Islands, it caused over $25 million in damage throughout the state.

While tsunamis are infrequent in Hawaii, it is vital to heed any warnings and get to high ground immediately as these waves can flood shorelines without much warning.

By understanding what causes tsunamis, learning from Hawaii’s history with them, utilizing today’s monitoring systems, and following safety tips, we can help protect lives and property in the rare event of another destructive inbound wave.

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