Massive tsunamis from small asteroid impacts

I believe the majority of people around the world are overlooking the threat of massive or even mega tsunami threats from the small size asteroids or space rocks which possibly number in the hundreds of thousands.

Many people may think of the movies where a killer asteriod would totally wipe out life on this planet as we know it but that chance is remote for the immediate future. The chance of a much smaller asteroid impact such as the one that struck Siberia in 1908 "the Tunguska comet" is much greater I believe.

The Tunguska comet or asteroid was projected to be only about 30 to 60 meters across and would have been difficult or unlikely to be detected by even the most modern ground telescopes in existence today.
www.permanent.com...

If instead this comet or asteroid had been a nickel-iron asteroid instead of the softer volatiles likely in the Tunguska comet and just a little bit bigger and hit the ocean, (which is a majority of the planet surface), it could cause a giant tsunami wave that could strike any major coastal city in the world in any of the world's oceans. I believe I heard that a really large tsunami could travel into all the world's oceans.

If one of these small asteroids struck without warning in the Atlantic Ocean, then would the US east coast or European cities be able to warn coastal populations of an impending tsunami? There are millions of people living within miles of the US east coast. I'm not sure if we have any tsunami warning system set up in place to warn and evacuate people.

I've read that there are over 300,000 near earth objects asteroids over 100 meters in diameter. The odds seem to be much greater for this type of impact scenaro. This type of impact may occur on average about every 100 years too. If Tunguska was in 1908, then the next Earth impact would be due to occur 3 years from now if it happened exactly at a 100 year interval. It could happen any day though without warning. These type of small asteroids are very difficult to detect and keep track of.

What do you think our governments would do if a 75 ft tsunami wave was going to hit the Atlantic Ocean or other world's oceans with only a few hours notice? I don't believe there is any plan in place that I know of to warn and evacuate so many at one time. This type of event I believe is very likely to occur sooner or later. Are our governments just going to be content to let people get destroyed rather than set up and plan for this? Of course one could argue that there is a 30% chance that such an asteroid would hit land and we wouldn't necessarily have to worry about it causing tsunamis. I really don't believe we are prepared and a little preparation may go a long way in saving lives.

Here's another link stating that most of these small near Earth asteroids under 100 meters go undetected.
neo.jpl.nasa.gov...


[edit on 8-1-2005 by orionthehunter]

[edit on 8-1-2005 by orionthehunter]

Are you trying to indirectly say that possibly a asteroid impact caused the earthquake and tsunami back the Dec. 26, 2004? Because no, just no. Here's why.

A.) There would be a streak of fire, ash, and smoke across the sky visible by thousands hundreds of miles away. Anything entering the atmosphere leaves a streak like that, especially if it entered into the lower parts of the atmosphere.

2.) Flash boiled water anyone? The heat from the asteroid would first instantly vaporize the water it came into contact with. That water then would enter the atmosphere, condense, and turn into just about the biggest rain storm ever.

C.) Where did all the ejecta go? That's the stuff that would be blown into the atmosphere from the impact woth the crust. The heat from the asteroid would keep the water above it from falling in above it, so there would be a clear path for it to blown up in.

4.) That leads to the next point. The heat from the impact then would boil away even more water, and the gaping hole in the crust down to the magma would again keep water from collapsing in on the crater. This would keep the hole over the crater in the water open for a long while.

My point is that no, someone would have seen this happen. Yes, an asteroid hitting the ocean or any other large body of water would displace A LOT of it and cause a tsunami, but again, someone would have seen it.

Also, if something like this did happen without warning, I think the government would do little to warn people. There wouldn't be enough time to evacuate cities (anywhere from say 30 minutes to 4 hours, depending on the strike) and pretty much everyone in the cities would be dead anyway. So they would probably just evacuate what higher officials they could and grit their teeth for the aftermath.

My first thought when I heard about the Tsunami was that it was an asteroid impact. The thing that made me suspect this was not the case was the aftershock quakes. Would you get aftershocks from an asteroid strike?

Originally posted by cmdrkeenkid
My point is that no, someone would have seen this happen. Yes, an asteroid hitting the ocean or any other large body of water would displace A LOT of it and cause a tsunami, but again, someone would have seen it.

Especially missing brighter than sun fireball rising from impact point might be little hard.

Also military satellites would immediately detect IR signature of explosion. (meaning some goverments might get really nervous really fast)

This test of small yield nuclear tipped artillery shell should show how bright even small explosion is, imagine what thousand times bigger one looks.
www.vce.com...


Tunguska sized explosion might not be enough, estimates for its power are commonly between 10 and ~30 Mts and biggest US nuclear test, ~15 Mt Castle Bravo (which should have been ~5 Mt device but they forgot something in calculations) was detonated on artificial island made over reef in Bikini atoll. There was also other big tests made on barges and on reefs but none of those caused tsunami.

The Bravo crater in the atoll reef had a diameter of 6510 ft, with a depth of 250 ft. Within one minute the mushroom cloud had reached 50,000 feet (15 km), breaking 100,000 feet (30 km) two minutes later. The cloud top rose and peaked at 130,000 feet (almost 40 km) after only six minutes. Eight minutes after the test the cloud had reached its full dimensions with a diameter of 100 km, a stem 7 km thick, and a cloud bottom rising above 55,000 feet (16.5 km).

nuclearweaponarchive.org...

This one was made by 10.4 Mt Ivy Mike:

The resulting crater was 6240 ft across and 164 ft deep.
nuclearweaponarchive.org...

Here's more...
Actually hit to ocean might be less devastating than hit to ground.
Because in impact to ground huge amounts of dust is send to sky whick blocks sunlight effectively causing "nuclear winter" while hit to ocean would simply vaporisize water and wipe out coastal areas.

Past impacts with water or ice are very difficult to detect, because they leave very little evidence. One such impact is known to have occurred in the South Pacific Ocean, near Chile, about 2 million years ago. This event -- known as "Eltanin" after the ship that discovered the deposits -- involved an asteroid between 1 and 3 miles in diameter that would have created a water crater at least 40 miles across. Tsunami would have swamped coasts around the Pacific and would even have reached some Atlantic coastlines. Assuming a typical run-up factor of three, the coast of Chile would have been inundated by 250-yard-high tsunami. Likely results for other locations: Hawaii 90-yard tsunami (probably higher due to the greater run-up factor); California, 60 yards; Japan and Australia, 25 yards; New Zealand; 120 yards.

Despite this presumed destruction to coastal areas, there is no evidence of global climate change or regional extinctions around this time, when our early ancestors, Australopithecus, were roaming Africa.

www.space.com...

I wasn't implying this past tsunami in the Indian Ocean was caused by an asteroid but I was implying the likelihood of one occurring from a small size asteroid is much higher than many expect.

I don't believe these small asteroid created tsunamis have to be that devastating if the US and other countries around the world set up warning systems. If one hit in the Atlantic Ocean, a few hours would be alot of time for many to evacuate. It's true that up to millions probably wouldn't be able to evacuate due to traffic congestion if a large asteroid hit but I wasn't necessarily arguing the case for evacuating in the event of a large asteriod. The only areas that would need to be evacuated would be areas with low elevation since the tsunami would be small.

I suppose the big question is how big does an asteroid need to be to create a tsunami and what minimum size tsunami would it create? A 10 or 20ft tsunami might be relatively easy to evacuate from with a few hours warning. I don't know if there is any warning system set up to even let the public know if such a small asteroid hit in the Atlantic Ocean. Of course if an announcement was made that a tiny asteroid hit in the Atlantic and it would cause a tiny tsunami, everyone would want to know time of tsunami impact, how big, etc.. If charts and graphs were shown over the Emergency broadcast system on TV to evacuate to higher ground or up to 1 mile inland, many lives and voters could be saved.

If a big tsunami or asteriod hit, I believe the government would keep it secret and evacuate the vip government personnel. I don't know what the official policy is but millions of homeless, displaced, and starving people would make the situation that much worse for everyone else. I haven't even heard if the US government has a policy for this situation though.

I thought of another question if anyone knows. If a small asteroid hit in the Pacific Ocean, would surrounding countries know about it in time to warn people? I know earthquakes are detected but I'm not sure if a small asteroid would necessarily cause an earthquake if it hit in the deep ocean.

[edit on 9-1-2005 by orionthehunter]

[edit on 9-1-2005 by orionthehunter]

Orion

The impact risk is real and increasing. ET and I have gone at this topic several times - read these links:

Catacylsm and the Taurid threat: www.abovetopsecret.com...

The Coming Cometary Catastrophe: www.abovetopsecret.com...'

IMHO there is NO doubt an impact is iminent. All science asgrees that it is not a matter of " if " but rather only " when ".

My hypothesis detailed in the threads as linked above , attempt to show that the likelihood of such impacts are likley to occur sooner rather than later as we as a planet are statistaically way overdue

Alias Jones

Originally posted by orionthehunter
such as the one that struck Siberia in 1908 "the Tunguska comet"

What is the basis behind this claim? I thought the 1908 Tunguska incident was still very much unexplained.

I believe Orionthehunter is absolutely correct.

A nickel-iron object with a diameter in the 100-meter range could cause incalculable damage.

E_T, I tend to disagree with your suggestion that a land impactor could be more dangerous than a sea impactor in the long term; here're three reasons why:

(1) Although the former could well kick up a lot more dust, a sea impactor would vaporize megatonnes of water, much of which would solidify as ice clouds in the high stratosphere, increasing the Earth's albedo drastically and possibly staying there for decades.

(2) A major portion of the water would fall as snow and ice polewards of both 30 deg North and South latitudes due to Coriolis winds. Even if the sky clears, a snow-pack from, say 45 degrees polewards would also increase albedo significantly. Nuclear winter would be almost a given.

(3) Finally, a really big sea impactor could possibly cause damage to the plates themselves. Remember that continental plates are much thicker and more felsic than the undersea one. A disruption of the relatively more thin and mafic undersea plates could result in hundreds of brand-new Hawaiis and Icelands, with the resultant atmospheric coverage from the volcanic activity. This would be much less likely if the object impacted an continental plate.

Statistically, such an impact won't happen for centuries to come, but remember, as Mark Twain said, "There are lies, there are damned lies, and there are statistics."

We need to invest in our space program to design and build a system which can warn us early in case a potential impactor is en route to the Earth -- and divert it when it does.

[edit on 10-1-2005 by Off_The_Street]

Originally posted by defcon5
My first thought when I heard about the Tsunami was that it was an asteroid impact. The thing that made me suspect this was not the case was the aftershock quakes. Would you get aftershocks from an asteroid strike?

Well the earthquakes, no matter where the asteroid/comet/what-be-it landed would follow something like this:

1.) Earthquake caused by the impact of the asteroid...

B.) The impactwould cause techtonic plates around the globe to shift, causing more massive earthquakes

3.) Aftershocks would follow from the techtonic earthquakes, not the impact earthquake.

Did that help clarify things? So if it were an asteroid impact there would have been other massive earthquakes, not just the one big one. Also, I would think that if it were an asteroid impact to cause the earthquake the epicenter would be at the seafloor, not some depths below.

Originally posted by MERC

What is the basis behind this claim? I thought the 1908 Tunguska incident was still very much unexplained.

You are correct I believe that the Tunguska event has not been proven beyond all doubt as to what caused it. However I am going with popular scientific opinion and my own opinion of what caused the event. Here's another link stating within that it is the popular scientific community reasoning too.

www.usm.maine.edu...

I would really be jumping on a limb if I stated that I believe Earth has had some small impacts back in the 1800's but the evidence suggesting so is much less. Of course I doubt people living in the wild west of the USA in the 1800's would know the difference between a wildfire and a blast wave from an impact. The frequency rate of earth impacting small asteroids 100 meters or less may occur every 100 years on average but that is mainly my guess estimate. If I'm right, I may get to hear of one during my lifetime though. I believe there are clues that even the dark and very cold middle ages or dark ages may have been caused by an impact. I just don't have the evidence to back up any of that. I'm not the first to state that theory though.

Edited note: I heard on the news that the earthquake and resulting tsunami in the Indian Ocean was a once in a 700 year event. I believe these small 100 meter or less asteroids or comets impact the Earth much more frequently on average. It makes logical sense that the more debris there is, the more impacts a large body such as the Earth will receive. I've heard that there is an atomic size explosion of debris in the Earth's upper atmosphere about once every year on average. Now I just noticed at the end of the link I posted above, the author of that link apparently put in a frequency rate of 50 meter impactors as once every 100 years.

[edit on 10-1-2005 by orionthehunter]

[edit on 10-1-2005 by orionthehunter] typo

[edit on 10-1-2005 by orionthehunter]

I was hoping by posting this thread that a little bit more public awareness of the threat would get people to think about tsunami warning systems. I believe having a tsunami warning system for people living on the east coast of the US or in other places around the world would be good insurance for whenever this does occur. A small asteroid or comet is already on a collision course for the Earth. I'm not saying one is going to strike soon but we just don't know if it will occur 5 years from now or 50 years from now.

I should restate that these small 100 meter or less asteroids are very likely to go undetected until impact. That would mean that any tsunami warning system would need to work very fast to warn people along the coastlines. I'm talking about warnings for tsunamis that are relatively small. Most people wouldn't have a chance if a big asteroid hit.

[edit on 11-1-2005 by orionthehunter]

Originally posted by orionthehunter

I believe there are clues that even the dark and very cold middle ages or dark ages may have been caused by an impact. I just don't have the evidence to back up any of that. I'm not the first to state that theory though.

I was going to just refer to this thread for additional information but after reading it again I decided to comment on what I wrote here. After recently hearing about 3 very large volcanic explosions during the middle ages, I now believe that is what likely caused the big drop in temperatures during the middle ages. Of course any new evidence could change my opinion again.

I believe I heard about this information again on a tv show called Megafreeze

www.history.com...

We might be able to do some planning to save lives due to small impacts in the ocean but I don't know what if anything we would do for a sudden climate change due to massive volcanic eruptions.

Here is a good link detailing comparisons.

For example, the model shows that waves radiating from the impact of a 300-metre-wide asteroid would carry 300 times more energy than the 2004 Asian tsunami
Source: newscientist.com