Tsunami warning issued for morning of Jan 15, 2022

[Cavedweller]

One geologist stated the explosion was one of the loudest sounds ever heard. It was heard over 5,000 mi away in Homer, AK. High water hit the coast of S. America.

 

[Mark W.]

So I understand the water can go a long ways inshore. But I have a hard time understanding how the water can go up hill. Granted if a 2.5" higher then normal wave hits a beach it will travel up the beach until it reaches land more then 2.5ft above where a normal wave would hit. How would that wave/water reach 4ft say?

 

[Ura-Ki]

So I understand the water can go a long ways inshore. But I have a hard time understanding how the water can go up hill. Granted if a 2.5" higher then normal wave hits a beach it will travel up the beach until it reaches land more then 2.5ft above where a normal wave would hit. How would that wave/water reach 4ft say?

Your on the right track, but don't forget surge velocity and the volume behind it that drives it! Take a measure of a known volume of water , add it's wave height, and it's speed, and multiply that times distance and gradient, that gets you close to an acceptable answer you can predict from!

 

[Cavedweller]

So I understand the water can go a long ways inshore. But I have a hard time understanding how the water can go up hill. Granted if a 2.5" higher then normal wave hits a beach it will travel up the beach until it reaches land more then 2.5ft above where a normal wave would hit. How would that wave/water reach 4ft say?

This is probably not a very elegant explanation, and a physicist could probably do better, but I'm guessing that it is being pushed uphill by the water behind it. It cannot recede as long as water continues to flow inshore. It's about wave length, not wave height.

 

[308]

 

[Ura-Ki]

Heads Up, New eruption, they are saying this new one is much bigger/worse then yesterdays, Tsunami warning expected any min. now, expect to see much larger waves and flooding! USGS is reporting but not posting data yet, which means it's still collecting data or they are expecting much more/worse then what currently shows!

I heard the sonic booms, around 7:40 p.m and then a second one around 8:20p.m, apparently the sound circled the earth TWICE!

Stay Sharp, especially those living near the coast, things could get a whole lot worse in the next few hours/days!

 

[Member 52301]

PBS had 2 shows about the massive destruction, flooding, loss of life, loss of buildings, loss of infrastructure, and the people who lived to tell the story in Japan.

Older news weather wise NOT about this storm here.

I think that they did a good job in producing and filming those shows.

In a few books, articles and online podcasts, a well known Japanese man who is an author about MINIMALISM talks about some people who lived through that horrific storm. Plus people who lived through other horrific storms and earthquakes all over Japan.

Imagine a storm - water surge spread so WIDE/LONG and I mean WIDE and LONG, that even if you went to HIGHER GROUND - in many cases, it would not matter because everything in it's wake just got SWEPT OUT TO SEA. SUCKED OUT TO SEA! Never to be found again or in only bits and pieces. The width/length of that one storm was so WIDE and LONG to see and some film footage showed it in slow motion. There were some cameras that survived in several strategic locations. So it was not just one thing - wave height - it was the WIDTH/LENGTH of destruction.

This has been mentioned here in this thread.

Some of the Japanese footage in those PBS shows showed more than what was only shown on American and European news.

You may still be able to find those shows online (Free!) and PBS sometimes repeats many of their old shows often on the boob tube too.

Cate
Typos!

 

[Cavedweller]

 

[RicInOR]

TikTok - Make Your Day

 

[Cavedweller]

 

[RicInOR]

 

[The B]

i think the whole problem with understanding tsunamis is in terminology... tsunamis are "waves" in a physics sense, but not in a nautical sense. out on the ocean, you have two totally different phenomena - wind "waves," and swells... the difference isnt exactly distinct in definition, but in experience theres massive differences. as a sailor, when im talking about "waves," im talking about wind waves, which are just ripples - breaking or otherwise - on the surface of the water caused by the boundary effect.. they are very short frequency, dont carry much energy, and just kind of splash around until they flatten out. and in fact most ocean swells start as the same thing, but are the result of cumulative causes and travel long distances and have more mass and more energy. wind waves stirred up by squalls and cyclones flatten out pretty quickly as soon as the winds die down, but kick out swell waves that travel for hundreds or even thousands of miles, often converging with other waves/swells, growing or shrinking in size, and can really carry a lot of energy for a long way. they "ride" (thats not how water waves work, but its the simplest explanation) the surface of the water until they get to land where their momentum toward shore pushes them up shore, depending on their velocity - swells/waves with lots of velocity and especially with lots of mass can push pretty goddamn far upshore/inland

if the swell is large enough, it basically acts like a tide - the water level effectively rises to the height of the swell, inundating low lying land before it can flatten out. people are often perplexed by video of tsunamis inundating land because it isnt the single large, fast-moving breaking wave they have in their minds... its as if the ocean level just rises rapidly, and water flows over walls and dykes (huhuhuhuh) relatively slowly.. like a flood tide.

tsunamis are just really big and usually really energetic ocean swells, not much different than you'd encounter from storm swells or surges (also kind of like a tidal effect, caused by atmospheric low pressure under a cyclone) except bigger, because theyre generally caused by land mass displacing huge volumes of water. if a hundred billion cubic feet of earth moves under water, it pushes that volume of water out of its way, and it aint stopping till it hits shore somewhere

remember when we called tsunamis "tidal waves?" a tidal wave is a real thing and can be destructive, but its origins are differwnt, they rare and never as destructive as big tsunamis, but calling tsunamis "tidal waves" isnt as inaccurate as they make it out to be. no, tsunamis are not tidal (that is, caused by the gravitational effect of the sun or moon) in nature, but that IS exactly how they behave - just like a massive flood tide.

it is kind of an awkward notion to grasp.. but maybe this helps someone..

 

[Lennie]

The shock wave from the blast was measured on the other side of the world

Pacific volcano: Science will explain event's ferocity

Researchers are moving rapidly to understand what drove Saturday's huge eruption near Tonga.

www.bbc.com

from the article
Meteorologists, both professional and amateur, immediately recognised that they might be able to detect the signal even on the other side of the world.
In the UK - which is about as far away as you can get from Tonga - the barometers wiggled at the expected moment.
"These things travel at the speed of sound, so on Saturday night quite a lot of people lined up expecting something. And that's what happened - a slight increase in pressure (about 1.5 millibars) followed by a decrease lasting about half an hour," explained Prof Giles Harrison from the University of Reading.
"The distance from Tonga to the UK is about 16,500km, and with an interval of about 14 hours - that gives you the sort of speed you would expect, at roughly 300m per second."
The Reading barometer had recorded a total three pulses by 7am UK time on Monday.

 

[RedRover]

It is not the height of the wave that matters in a tsunami. It is the amount of water behind it (wave length) it and how far inland it travels. They don't always stop on the beach like normal ocean waves. The farther inland it travels, particularly in populated areas, the more debris it tends to carry out to sea when the wave recedes. Then subsequent waves are a churning mass of water and debris which are particularly dangerous to anyone trapped in the water.

"Tsunamis have a small wave height offshore, and a very long wavelength (often hundreds of kilometres long, whereas normal ocean waves have a wavelength of only 30 or 40 metres),[34]which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimetres (12 in) above the normal sea surface. They grow in height when they reach shallower water, in a wave shoaling process described below. A tsunami can occur in any tidal state and even at low tide can still inundate coastal areas." from wikipedia.

Here is a good video from Japan showing how a very small in height wave becomes particularly destructive as the massive amount of water gets channeled up a river estuary.

The footage from the 2011 Japan Tsunami is absolutely incredible.

Here's what the same location looked like only two years later. Surprisingly a lot of structures survived. Spinning around, one can see the steps leading up to the footbridge that was washed away, and the work being done to set the pylons for a new bridge.

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.com

The building(s)(school?) where the people and cameraman took refuge looks to have been demolished. All that remains is a barren field.

 

[RicInOR]

The Tongan government released its first update after a massive volcanic eruption and resulting tsunami hit the island nation, calling it an "unprecedented disaster." The country is reporting nearly all the homes on two islands were destroyed, with three confirmed deaths—a 65-year-old woman, a 49-year-old man, and a British citizen. The number is expected to rise as the government has been unable to reach several inhabited islands—communications were scarce after an underwater cable was cut off in the eruption. In addition, ash has coated the main island, contaminating drinking water and delaying international relief flights. Separately, unusually high waves after the eruption caused an oil spill covering almost 2 miles of Peru's central coastline. See before and after photos of the damage in Tonga here.

 

[Lennie]

Very interesting information

MSN

 

[Cavedweller]

Most energetic explosion since the 1883 eruption of Krakatoa.

 

[RicInOR]

An undersea volcanic eruption occurred 40 miles off the coast of the South Pacific country of Tonga on Saturday.

Satellite imagery shows the eruption unleashed a massive shockwave as a plume of ash was flung 12.4 miles into the atmosphere.
US Storm Watch said the eruption was the "most violent" eruption ever captured on satellite footage.


Some have compared the eruption to the "Hiroshima" nuclear bomb explosion.

https://twitter.com/x/status/1482229220415721475

Tonga undersea volcano eruption released up to 18 megatons of energy.

 

[bionic knees]

but the govt is concerned about the emissions from my diesel pickup.