Can this happen? Well… Will this happen? Not in my lifetime, nor that of many generations to come, and maybe never. Scientists who bother might prove that this is not possible, and might find flaws, maybe even fatal ones. But the fact of the matter is that a far field mega-tsunami created by a major landslide has never happened in recorded history. Thus, all models cannot back check with reality. There are non-linear factors involved and sufficient noise from both sides of the controversy that one can’t totally rule out the possibility.
But, like the re-creation of H.G. Wells War of the Worlds, where, if you listened at the beginning, you should have heard that this was a Halloween fictional yarn, let me underscore that this tongue-in-cheek artifice, is provided as an extreme case of a natural hazard not commonly acknowledged for the sake of public education. But in my tale, is Seattle destroyed by this 100 meter monster? A weak no. All the science points to a tsunami of relatively short period, which will rapidly decay with substantial height attenuation. It is possible that Seattle could experience a three meter tsunami, but most probably something on the order of one meter. That was the scenario in 2004.
In the Third Tsunami Symposium, held from May 26-29, 2006, in Honolulu, I learned several more things which swayed me even further towards rationality. First, the Los Alamos National Laboratory multiphysics SAGE code was used to analyze the possible La Palma conditions—375 cubic kilometers, 75 kilometer runout in 9 miles at a speed of 140 meters per second—and produced a 500 meter tsunami, but in the general south southwest direction, not towards the United States. The purported 50 meter tsunami hitting Florida was calculated to only be 1.3 centimeters. Yes, the damage to the Canaries, and even Africa and parts of Europe (Portugal and Spain) would be severe, but the diminution of size over distance would be significant because of the short period. The Stanford ASC Center using a different model pretty much reinforced the Los Alamos report.
Finally, at the all-day tsunami tour, I was flabbergasted to learn that while I was a senior in high school, a 55 foot tsunami run-up occurred in Kahuku from a 1957 Alaskan earthquake, close to the Turtle Bay Hotel (where the EnergyOcean conference was held in 2007). Nothing in my memory remembers this. Although I never lived further than half a mile away from the beach all my early life in Hawaii, my only recollection about an incoming tsunami was when I was six years old or so, a friend and I began to dig a hole in our yard to draw the water just in case it made it into our neighborhood. Yes, we were reprimanded for being so stupid, made even more dumb because the minimal tsunami (but major in Hilo) on the south shore of Honolulu had already come and gone when we began our excavation project. But the good intent was there.
Back to the tour, just about the time we were at that 55 foot Kahuku site, my colleague, Dailin Wang, who had recently transferred from the University of Hawaii to the Pacific Tsunami Warning Center, got a beep, and noted on his electronic device that a 5.8 earthquake had just hit in the ocean on the opposite side of Sumatra from the big one which devastated the region the day after Christmas. In the minutes that followed there seemed to be no tsunami generated, so he did not have to rush back to the center. The tour group later went to the Center, but I had to move on to other things. I later learned that the actual earthquake was of 6.4 magnitude, and it occurred on land, killing more than 5,000 and leaving 200,000 homeless. This should not be confused with the 2004 Indian Ocean earthquake, which on December 26 killed 230,000. I guess the point to this story is that it is difficult to make a quick assessment with current technology. Someday, the instruments will get better and the communication system improved.
Thus, Seattle, you can sleep comfortably. You won’t even have to be concerned about a tsunami of a meter. Sorry, Hawaii, for gone will be the northeast side of the Big Island. Plus, the tsunami devastation back up the chain, will be devastating. While this tsunami points towards Seattle, there is a rearward effect that will very significantly affect Kailua-Kona, Kahului, Kaanapali, Honolulu and Lihue.
How seriously? It does not matter, for the odds of such an event are too remote to ponder. Yet, if such a landslide were to occur on the west side of the Big Island, a 300 meter tsunami could well hit Waikiki Beach, because it would be in the reasonable near field. Plus, too, the Swiss Federal Institute of Technology apparently still sticks by its lab results done for that UK group, so, who knows, maybe they could be right and that tsunami hitting Seattle could very well be 100 meters, or more. Whether it’s Six Hours to Seattle or Half an Hour to Honolulu, I really haven’t yet settled on the details. There could, well, be too, Twelve Hours to Tokyo, when the Hawaii tsunami triggers the fall of the San Andreas Fault, creating a mega-tsunami towards Japan. That might be Book 4.