As you drive around the Big Island, you see signs like this one, letting you know when you are entering and leaving tsunami evacuation areas, so you can know how far inland you must go for safety in case of an incoming wall of water, the consequence of a distant earthquake.
The Pacific Tsunami Museum, located in a former bank building in downtown Hilo, is a very sobering place. Here you can learn about tsunamis that have happened around the world over the years, including the huge 1960 one that swept through that very building. You enter the former bank vault to watch a video where survivors of the tsunami describe their experiences. It's a sad place.
One of the tragedies of the 1960 tsunami is that when the ocean began receding, the people didn't realize that this was a sign that a tsunami would soon be coming. So many of them ran down to the shore to gather fish, resulting in their deaths when the wall of water arrived. So, if you happen to see the ocean receding, or if you ever feel an earthquake when you are at an ocean beach, move to high ground immediately.
You can see from this map that whenever there is an earthquake along the edges of the pacific tectonic plate, Hawaii is at risk for a tsunami. (Click on the image to see a larger, more-readable version)
Hilo has been hit by tsunamis many times. I was interested to learn that it is the one place where the airport will close as a result of tsunami warnings, because they've learned that they need to use the runways as emergency roads in order to quickly evacuate some of the residential neighborhoods nearby.
They've also stopped rebuilding the portion of town that sits right along the waterfront. That's why the bank building no longer serves as a bank, but instead as the Tsunami museum, seeking to educate and prepare people.
As with much of life, beauty often comes of tragedy. Because they don't build along the waterfront in Hilo, they have many beautiful parks there instead. One of my favorites is the Liliuokalani Gardens, the largest formal Japanese garden outside of Tokyo.
Here's one of the beautiful Japanese gates there:
And the lovely red bridge:
And the beautiful trees: