Pedantic pet peeve: Decimate is not a synonym for destroy. Deci- = 1/10th or 1 in 10..
Rest is fine.
From Hakai Magazine, February 16:
Gigantic tsunamis have been decimating coastlines since time immemorial. We ignore these prehistoric warnings at our own peril.
A boulder weighing more than 40 tonnes sits on the sand high above the ocean. Dwarfing every other rock in view, it is conspicuously out of place. The answer to how this massive outlier got here lies not in the vast expanse of the Atacama Desert behind it but in the Pacific Ocean below. Hundreds of years ago, a tsunami slammed into the northern Chilean coast—a wall of water 20 meters high, taller than a six-story building, that swept boulders landward like pebbles.
The tsunami that lobbed this behemoth happened before written records existed in Chile. But we know about it today thanks to the detective work of a small group of researchers who are uncovering the signs of ancient tsunamis around the globe. Using a diverse array of scientific techniques, these paleotsunami researchers have found evidence of previously undocumented colossal waves. In the process, their work is revealing that coastal communities could be in far more danger from tsunamis than they realize.
As scientists expand their search, they have continued to find ancient tsunamis bigger than those found in historical records, says James Goff, a paleotsunami researcher at the University of Southampton in England. The implications are clear: if a huge tsunami happened once in a given location, it could happen again. The question is whether we’re prepared for it.
A tsunami is more than just a big wave. Conventional waves, even those tens of meters high, are usually generated by the wind and involve only the uppermost layers of water. They carry relatively little energy, and typically crash harmlessly on the shore.
A tsunami, by contrast, is spawned by geological forces—an earthquake, volcanic eruption, or the side of a mountain crashing into the sea. A tsunami involves the entire water column. While large tsunamis can measure 20 meters or more in height—with some particularly monstrous ones rising hundreds of meters—they need not be exceptionally tall to cause widespread damage. Instead of collapsing on the beach, a tsunami rushes ashore like a battering ram. After racing hundreds of meters or more inland, the water recedes into the depths, carrying away nearly everything in its path. But tsunamis almost always leave evidence of their passage—like an out-of-place boulder high in the desert.
Goff has been searching for ancient tsunamis for almost three decades, mostly in countries bordering the Pacific Ocean. He’s one of just a few scientists worldwide who specialize in finding evidence of paleotsunamis, or tsunamis that predate written records.
The easiest way to tell that a tsunami hit hundreds or thousands of years ago is to look underground, Goff says. When the wave recedes, it leaves traces of everything it contained strewn across the surface. This thin layer of silt, rocks, tiny shells, and other marine deposits gets buried over time, preserving the tsunami’s path between layers of sediment. In some places, the layers are so well preserved that researchers can see evidence of multiple tsunamis stacked on top of each other like a layer cake....
....MUCH MORE
If interested see also paleotempestology, not directly related but fun to say:
....When a business/finance researcher uses language like "With supercharged hurricanes, massive floods and unprecedented wildfires sweeping the globe" you can tell he's a newbie to the science.
Just yesterday I was looking for hurricane data from the Roman Climatic Optimum and the Minoan Warm Period and the so-called paleotempestology gets pretty sparse at even 1200 years ago, much less 2000 and 3500.
And that's just a moment ago in time. If we are looking back to previous interglacial periods what were the hurricanes like in the Eemian interglacial, 125,000 years ago? Or the one a quarter-million years ago? Or the interglacial a million years ago. And 50 million years ago? 500 million?
Just what are we comparing the present to when we make these sweeping statements?
We just went through an 11-year period 2006 - 2016 with zero cat 3 and above landfalling hurricanes hitting the U.S. Is that our baseline?
None of the coupled climate models had that happening. (Sandy wasn't much more than a giant tropical storm when it made its New Jersey landfall but throw in a landing at daily high tide and the full moon monthly high tide and Chris Christie walks President Obama to re-election)
The thing is, we just don't know what is "normal" and all we can do is hope that our recency bias doesn't lead us into some very dark (literally and politically) places as we feel our way forward.
