5 ms·
Megatsunamis: Waves over 500M high and devastation beyond the ocean
- rurban 3y agoThe most devastating tsunami would be a Cumbre Vieja rock fall, at the Canares Islands, impacting Brasil, Caribbean and partially Florida. https://en.m.wikipedia.org/wiki/Cumbre_Vieja_tsunami_hazard https://en.m.wikipedia.org/wiki/Cumbre_Vieja_tsunami_hazard There is no need for a 100m megatsunami, 5m is enough. The mass is critical, not the height
- toomanyrichies 3y agoCool simulation of the July 10, 1958 Lituya Bay tsunami in Alaska, mentioned at the top of the article: https://www.youtube.com/watch?v=cegaVqMvvvQ&ab_channel=SurferToday https://www.youtube.com/watch?v=cegaVqMvvvQ&ab_channel=Surfe...
- ginko 3y agoThe symbol for meters is a lower-case m.
- jagrsw 3y agoIn US it also seems to be popular to use L for liter (or litre:)
- ginko 3y agoUppercase L is the correct symbol for liter adopted by CIPM. At the very least both l and L are generally accepted. M is definitely wrong for meter though.
- pif 3y ago> Uppercase L is the correct symbol for liter adopted by CIPM. Uppercase L is the alternative symbol for liter adopted by CIPM.
- moffkalast 3y agoThey clearly meant 500 million high.
- delta_p_delta_x 3y agoAnd it has to be spaced from the measure: > The numerical value always precedes the unit and a space is always used to separate the unit from the number. Thus the value of the quantity is the product of the number and the unit. The space between the number and the unit is regarded as a multiplication sign (just as a space between units implies multiplication). The only exceptions to this rule are for the unit symbols for degree, minute and second for plane angle, °, ′ and ″, respectively, for which no space is left between the numerical value and the unit symbol. > This rule means that the symbol °C for the degree Celsius is preceded by a space when one expresses values of Celsius temperature t. > Even when the value of a quantity is used as an adjective, a space is left between the numerical value and the unit symbol. Only when the name of the unit is spelled out would the ordinary rules of grammar apply, so that in English a hyphen would be used to separate the number from the unit. [1]: https://www.bipm.org/documents/20126/41483022/SI-Brochure-9.pdf#page=151 https://www.bipm.org/documents/20126/41483022/SI-Brochure-9....
- euroderf 3y agoTIL! Still tho, cannot abide by this. It would make a units-filled sentence irritating to parse.
- jagrsw 3y agoSomehow 500m high tsunami destroying "only" 3.5 sq.km. of land doesn't strike me as monstrous. I was thinking it can maybe reach 5-10 km. into the land.
- branko_d 3y agoFrom the article: "Paradoxically, megatsunamis are not necessarily the most destructive, nor are they always synonymous with devastation."
- poulpy123 3y agolooking at the simulation posted here, it's because the water heigh wasn't so much due to the energy that created the tsnuami but of the geographical configuration. So the nergy dissipated quite quickly and didn't do much damage
- Cthulhu_ 3y agoWavelength vs height; the undersea earthquake tsunami has long wavelength but not a lot of height, but there is more water and force behind it so it's pushed further inland. These ones are like a big splash, high waves but not a lot of horizontal impulse in comparison.
- pif 3y agoPlease correct the title: "500M" should become "500 m".
- Qem 3y agoIs there a simple way to calculate the reach of a tsunami? Like, a tsunami of height x meters will penetrate over y kilometers inland if the terrain is flat, z kilometers if there is a 5 degree uphill declivity, w hundred meters with 10 degree declivity, et cetera.
- Enginerrrd 3y agoYou might be able to come up with some heuristics, but it won't be very useful. Your best heuristic is probably just to take the wave height and compare to the terrain elevation. Then... add a multiplier. Numerical simulation is your friend here. And... it gets really complex. There are different simplifying assumptions made to make the calculations tenable. Where run-up is a problem, it typically happens where wave interactions or terrain create concentrations of flow and increased wave height. Roughness of the terrain matters too, not just slope. You can probably get pretty close with off-the-shelf software just by doing a 2D HEC-RAS simulation with a terrain DEM and creative boundary conditions to simulate different wave heights, and a small time-step.
- pif 3y agoHeight without wave length is pretty useless. Normal storms come with waves way higher than most tsunami, both when approaching the shore and even more in the open sea.