It hasn't? You sure about that? Below is one small incident that happened just a few decades ago. In the scientific world this is called an analog for what will eventually happen with the La Palma fault block.
Lituya Bay’s Apocalyptic Wave
Eyewitness reports describe a chaotic and surreal scene: Intense shaking for several minutes, an explosive boom, and a shattered glacier soaring hundreds of feet into the air. Then a series of giant waves dotted with hunks of ice raced through the bay. One fisherman described his boat being lofted over a forested spit on the crest of one wave and looking down at trees below. The wave obliterated a cabin on Cenotaph island and swept away a lighthouse near the mouth of the bay. One couple that had been fishing when the wave hit were never heard from again.
The damage line in the forest—geologists call it a trimline—generally extended to an elevation of 700 feet (200 meters) around much of the bay. On one ridge opposite the slide, waves splashed up to an elevation of 1,720 feet (524 meters)—taller than New York’s Empire State Building. The event at Lituya Bay still stands as one of the
tallest tsunami waves known to science. The photo above, taken in 1958 after the tsunami, shows the ring of damage around much of the bay.
Evidence of the cataclysmic wave is still visible from space more than 60 years later. As seen in the false-color Landsat 8 image (
bands 7-5-3) at the top of the page, the damaged trimline is still imprinted in the forest. The lighter green areas along the shore indicate places where forests are younger than older trees (darker areas) that were not affected by the tsunami. When the tsunami hit, it snapped all of the trees and scoured away almost all vegetation. Some 2 square miles (4 square kilometers) of forest were sheared and swept away by the tsunami waves.
One of the tallest tsunami waves known to science slammed this Alaskan bay in 1958.
earthobservatory.nasa.gov