The Hawaiian landscape has undergone cataclysmic changes many times in the past.

Some of the islands are bordered by towering cliffs.

Far below, just offshore, lie vast deposits of rubble. They provide clues to how these sheer cliffs were formed.

Walter Dudley is a geologist at the University of Hawaii.

Dudley: These enormous majestic cliffs for years have puzzled geologists, by their sheer size. The normal rates of marine erosion just couldn’t create these cliffs in the time that was available. And it wasn’t until the sea floor was mapped around it we discovered they weren’t produced merely by marine erosion but by enormous landslides, where whole chunks of the island fell off into the Pacific Ocean.

Evidence of these giant slides can be seen all around the islands. Scientists have identified at least 17 underwater rubble zones, covering thousands of square miles of seafloor.

Dudley: For me to be able to stand at the top of these sheer cliffs, and realize that in one catastrophic event much of that coastline had fallen down and slid off into the Pacific Ocean … awesome feeling… one is just amazed by the power of Mother Nature.

The events that left behind cliffs like these were no run-of-the-mill rockslides.

Dudley: The Hawaiian islands and every other island in the pacific has been sculpted by the force of these landslides. We’re talking about an incredibly large volume of material… thousands of cubic kilometers of material, all at once, just like these masses behind me… sliding off into the Pacific Ocean…

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