Alaska is the most seismically active state in the U.S., and one of only five states along the Pacific Ring of Fire. Besides earthquakes, coastal communities in the state are also at risk for potentially deadly tsunamis.

A large earthquake, volcanic eruption or landslide could trigger a tsunami at anytime, meaning those near Alaska’s waters need to be prepared. A prime example is the tsunami that followed the 1964 earthquake. While the earthquake claimed only nine lives, more than 100 people were killed by the large waves that rushed the shores of not only Alaska, but also Washington, California, Oregon and Hawaii.

According to the National Oceanic and Atmospheric Administration, 420,000 have lost their lives in a tsunami since 1850.

Here’s how it happens: if a large amount of water in the ocean is suddenly moved, say by the ocean floor suddenly being raised up or dropped down by an earthquake, a tsunami or series of waves is generated.

Once formed, they travel across the ocean, until they hit land.

For the coastal communities near the cause of the tsunami, large waves can come to shore in a matter of minutes, even before the shaking stops.

In the open ocean, the waves travel fast, but are generally less than a few feet tall. They don’t stay that way though — when they reach shore, a tsunami wave’s height can be over 100 feet tall. When the waves reach the shallow water near the shore, it slows the wave down, but the energy doesn’t stop and the wave grows taller.

This isn’t just a large breaking wave — tsunami waves can extend inland 1,000 feet or more, taking out anything in their path, with more, potentially even larger, waves to follow.

If you live in a tsunami prone area, or ever visit one, it’s important to know what to do to stay safe. During Tsunami Week in Alaska, local and state agencies will be practicing for real-life situations involving tsunamis, which includes testing of tsunami alert systems. At 10:15 a.m. on Wednesday, a tsunami warning test will be conducted by the National Tsunami Warning Center in Palmer and transmitted through the National Weather Service EMnet interface to Alaska stations in coastal areas, according to the Alaska Division of Homeland Security and Emergency Management.

While the alert will just be a test, Alaskans in tsunami-prone areas should be prepared to evacuate to higher ground quickly in case of a real tsunami. The Red Cross of Alaska recommends checking how high the street you live on is above sea level and how far away from the coast. A plan of evacuation is also important, and the Red Cross said one should be in place for wherever you are, whether you’re at home, at work or in another area you frequent.

“You should be able to reach your safe location on foot within 15 minutes,” according to the Red Cross website.

An emergency kit is also recommended, one that can be grabbed quickly from your home or vehicle in the event of an evacuation.

For more information on tsunami preparedness, visit the Red Cross’s website.

KTVA 11’s Meteorologist Melissa Frey contributed to this report. Contact her at or follow her on Facebook and Twitter.