Tsunami in Asia

ERRORIST · 2005-01-12 08:28:48

This guy is way off from what I hear and read. The Tusnami would be 100 times that high at the least.

SpaceNut · 2005-01-12 08:54:57

Distance and depth of water contributes to wave hieght, not just size of the impactor or its velocity. The same holds true for under sea quakes, location and depth.

ERRORIST · 2005-01-12 09:12:51

Look at the water displacement occuring at 23,000 mph assuming it didn't break apart.

SpaceNut · 2005-01-12 10:55:20

You mean the 23,000 mph is from re-entry, I do not belive it would be going that fast when it would hit but that would also preclude 100% transfer of all the energy on impact of the water surface as well.

ERRORIST · 2005-01-12 13:55:11

This is an average of most impact computer models. Some comets hit at 100,000 mph. But, they break up more upon impact. But, most of the comets are larger.

ERRORIST · 2005-01-12 14:21:13

Here are the calculations for an Iron meteor 1/2 mile wide. If you notice it does not slow down very much before impact. It would be a devestating wave of over 1000 feet swamping Miami if it hit 100 miles off shore. The AIRBLAST would blow down tall buildings if it hit 100 miles offshore.

Impact Effects
Robert Marcus, H. Jay Melosh, and Gareth Collins
Your Inputs:
Distance from Impact: 160.00 km = 99.36 miles
Projectile Diameter: 792.48 m = 2599.33 ft = 0.49 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 20.93 km/s = 13.00 miles/s
Impact Angle: 45 degrees
Target Density: 1000 kg/m3
Target Type: Liquid Water of depth 457.20 meters, over typical rock.
Energy:
Energy before atmospheric entry: 4.57 x 1020 Joules = 1.09 x 105 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 8.3 x 105years
Atmospheric Entry:
The projectile begins to breakup at an altitude of 17500 meters = 57400 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 20.8 km/s = 12.9 miles/s
The impact energy is 4.51 x 1020 Joules = 1.08 x 105MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 1.22 km by 0.861 km
Major Global Changes:
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.
Crater Dimensions:
What does this mean?

The crater opened in the water has a diameter of 21.3 km = 13.2 miles

For the crater formed in the seafloor:
Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.

Transient Crater Diameter: 12.3 km = 7.63 miles
Transient Crater Depth: 4.35 km = 2.7 miles

Final Crater Diameter: 17.1 km = 10.6 miles
Final Crater Depth: 0.696 km = 0.432 miles
The crater formed is a complex crater.
The volume of the target melted or vaporized is 2.17 km3 = 0.521 miles3
Roughly half the melt remains in the crater , where its average thickness is 18.3 meters = 60.1 feet
Thermal Radiation:
What does this mean?

Time for maximum radiation: 0.737 seconds after impact

Visible fireball radius: 13.3 km = 8.28 miles
The fireball appears 18.9 times larger than the sun
Thermal Exposure: 7.02 x 105 Joules/m2
Duration of Irradiation: 19.9 seconds
Radiant flux (relative to the sun): 35.2

Seismic Effects:
What does this mean?

The major seismic shaking will arrive at approximately 32 seconds.
Richter Scale Magnitude: 7.9
Mercalli Scale Intensity at a distance of 160 km:

VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.

VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

Ejecta:
What does this mean?

The ejecta will arrive approximately 183 seconds after the impact.
Average Ejecta Thickness: 4.97 cm = 1.96 inches
Mean Fragment Diameter: 3.16 cm = 1.24 inches

Air Blast:
What does this mean?

The air blast will arrive at approximately 485 seconds.
Peak Overpressure: 56200 Pa = 0.562 bars = 7.98 psi
Max wind velocity: 109 m/s = 244 mph
Sound Intensity: 95 dB (May cause ear pain)
Damage Description:

Multistory wall-bearing buildings will collapse.

Wood frame buildings will almost completely collapse.

Glass windows will shatter.

Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

Palomar · 2005-01-12 15:25:43

http://story.news.yahoo.com/news?tmpl=s … Ostracized forecaster restored to honor

*Not sure about his claims of the U.S. being partly to blame, though, i.e. warning system based in Hawaii. Those folks apparently didn't have the correct phone numbers, but then the officials in the nations affected didn't supply them either or ensure they were available. One hand washes the other...

And apparently once the event happened it was already too late to send out a warning. In a different report I read or heard (can't recall which), folks in Hawaii DID try to send warnings.

--Cindy

ERRORIST · 2005-01-12 15:35:23

It reminds me of a four way intersection with stop signs. The officials know an accident will happen there. After a fatality occurs then they put up the stop light. Insane if you ask me.

SpaceNut · 2005-01-14 14:06:57

On the other side of the archelogy science teams now in india are looking for past history of such events.

Indian town sees evidence of ancient tsunami
Once-powerful city on same spot 'swallowed by the sea'

The ancient Thirupallavaneeswaram Temple is one of the few remnants of ancient Poompuhar, which was a thriving capital city until it was "swallowed by the sea" more than 1,500 years ago.

This particular article goes into the ancient times when this city did flourish and then suddenly was no more.

Palomar · 2005-01-19 10:07:25

*First off, the tsunami death toll now stands at an unbelievable 226,000. That's according to a Yahoo! news article I saw this morning.

http://www.livescience.com/forcesofnatu … tml]Oregon Well Records Quakes Around the Globe

I was going to create a separate thread for this, but figured since it discusses the Dec. 26 tsunami quite a bit, I'd post it here.

The well was drilled 300 feet deep and it's "recorded" every earthquake with a magnitude of 7.4 or greater since 1989.

Roeloffs, who has studied the well for more than a decade, said the earthquake that unleashed the devastating Asian tsunami last month roiled the water for more than five hours in a monitoring well 8,429 miles away in Southern Oregon.

They say it's usual for wells in general to register water-level fluctuations during quakes, but this particular well is more sensitive than most.

In the case of the Dec. 26 tsunami quake, the well's water rose and fell every 20 seconds. The maximum change in water level during one of the cycles was almost 18 inches.

I think this is the first time I've heard of monitoring earthquakes via water wells. Fascinating.

--Cindy

RobS · 2005-01-20 23:54:47

The reference to the tsunami caused by an asteroid impact being ten feet high may refer to its height mid ocean. The Aceh tsunami was only a foot or so high out in the ocean; fishing boats a dozen miles off the coast of Sri Lanka were completely unaware of the tsunami and did not learn about it until they returned to port at night and discovered their home port didn't exist any more.

The thing to remember about tsunamis is not the height, but the wavelength. A typical wave caused by wind can be thirty feet (10 meters) high out in the ocean, or even sixty or (rarely) more feet high, but the wavelength (the distance from one crest to the next) is usually a few hundred feet (say, 100 meters). That means the wave of water is 10 meters high, but not very wide, because the trough is just fifty meters behind the crest. You basically have a wall of water fifty meters wide and ten meters high moving across the ocean surface.

But a tsunami has a wavelength of several hundred kilometers instead. So the swell of water, out in the middle of the ocean, is only one meter high, but it is maybe 100 kilometers wide. Furthermore, waves move across the ocean at a speed proportional to their wavelength, with tsunamis moving hundreds of kilometers per hour, as opposed to wind-driven waves moving at tens of kilometers per hour. One more thing; a wave feels the bottom when the water depth equals half the wavelength. Thus tsunamis always feel bottom whereas wind-driven waves are just surface phenomena.

So you have the energy of a low swell being propagated through the water at hundreds of kilometers per hour, raising an ocean a meter or more for over 100 kilometers. When that "wave" suddenly reaches shallow water (less than 100 meters) all that energy in the entire ocean column gets concentrated into the shallow surface, pushing up a much higher wave, but a wave that is still a hundred kilometers or so wide. Thus the shoreline experiences a rise in sea level and a rush of water that lasts for ten or fifteen minutes, not just a few seconds; the water pours inland, flooding everything, and the deeper water moves faster than the shallow front so it keeps catching up with it and surging forward. Then the trough arrives and the sea drains back, exposing sea bottom that is up to a few tens of meters deep; then the next trough arrives with another huge, mad rush. . . . some tsunamis can have six or eight crests. The Aceh one had two.

This is what a tsunami is. An asteroid might propogate a swell of water few tens of meters high across the mid ocean, but when it reaches a shore it will rear up to hundreds of meters.

-- RobS

SpaceNut · 2005-02-03 09:54:28

Something that would go a long ways is earthquake detection.

Italians Make Earthquake Detecting Space Probe

This probably deserves its own thread but it is pertinent to the cause of a tsunami.

Italian scientists say the probe might be able to give a 4 to 5 hours advance warning of quakes by picking up variations in the radiation belts surrounding the Earth.

Grypd · 2005-02-03 10:38:11

The British goverment now have plans to develop a Tsunami detecting service for the western hemisphere.

It is something everyone has to realise is that Tsunamis can occur anywhere that there is a large area of water. The American continent Eastcoast and Europe have no real Tsunami detection service either. The Tsunami in the Indian Ocean was a wakeup call, a tragic one and we do need to do something better. As an example the Japanese have the best Tsunami detection service in the World they detected the one in the Indian Ocean but due to not haveing anyone to tell all they could was watch. The Pacific has a good one and soon will the Indian ocean. But what about the Atlantic. And this question was asked of a geologist in Aberdeen university could it happen. His answer "Oh yes, actually geologically speaking they are very common"

SpaceNut · 2005-02-09 14:41:54

Tsunami death estimate 6 weeks after event are still climbing.
Death Toll In Asian Tsunami Disaster Tops 295,000

Quake estimate of 9.3 on the rickter scale not 9.0, and thus was three times larger. The largest earthquake ever recorded, which measured 9.5, was in Chile on May 22, 1960.

We all know that having a better Seismic Network Could Improve Disaster Response

Palomar · 2005-02-10 14:28:52

http://story.news.yahoo.com/news?tmpl=s … 355]Seabed at tsunami's center shows ruptures

*They've found huge ruptures which span several miles on the floor of the Indian Ocean, via images obtained from a British naval ship.

"There are features which we would think are something like the Grand Canyon would look," Tim Henstock, a scientist aboard the HMS Scott, told BBC News. "You can see huge piles of mud maybe a few hundred meters (yards) thick."
The images show "slide scars" more than six miles wide...

Even worse: Human death toll expected to continue rising by 500 persons per day for weeks to come yet...maybe even months.

Still so unbelievable.

--Cindy

REB · 2005-02-10 15:18:33

A little off-topic.

http://www.iris.edu/seismon/]Quake in Arkansas

I don't recall ever seeing one in Arkansas in recent times.

Palomar · 2005-03-02 16:01:07

http://story.news.yahoo.com/news?tmpl=s … ]Indonesia rocked by another 'quake: 7.5 on Richter Scale

*...northern Australia apparently also got shaken up. Scientists doubtful it'll cause another deadly tsunami.

"It is highly unlikely the quake could trigger a tsunami since its focus is located too deep under the sea. We have not received any reports of tsunami over the last two hours," said Suyanto of the meteorology and geophysics office in Jakarta.
An official of the Japanese meteorological agency added: "No tsunami can be expected of an earthquake which occurs 100 kilometers (62 miles) or more below."

--Cindy

SpaceNut · 2005-03-18 13:23:52

And the possibility of more quakes continues as the stress level rises.
Indian Ocean may face another quake; Seismologists warn stress building on Sumatra faults

A buildup of stress on faults in Sumatra is likely to trigger another large earthquake — and potentially another tsunami — in the Indian Ocean region, seismologists say.
Another rupture could trigger a magnitude 7-7.5 quake on either fault. That would be a significant quake, but far less powerful than the one that unleashed a tsunami that left an estimated 300,000 people dead or missing.

Thou the prediction was not made, they do however concur that one is not to far off in that area of the world.

Grypd · 2005-03-28 15:25:00

There has been another quake off sumatra this one 8.7 richter scale

It was of one of the other stress fault lines that have had pressure increased since 26/12/2004 and was a shallow event about 19 miles below the surface. It did register as a possible another Tsunami event but it appears luckily enough that no such event has so occured.

What it did do to Indonesia was to collapse buildings and do further damage to the already stressed damaged structures. There is no count of the dead yet and there will be casualties.

edit It was just off the province of Aceh, and still no word of any Tsunami

DonPanic · 2005-03-28 15:57:20

LO
French "Institut de Physique du Globe" searchers told that if a tsunami wave should happen from this late earthquake, it would be 1/30 as powerfull as the one that made over 300000 victims.

Palomar · 2005-03-28 18:01:20

http://story.news.yahoo.com/fc?cid=34&t … onesia]Yet another Indonesian quake :-\

*Three hundred people dead from this quake. Sparked tsunami fears of course...which didn't come to fruition, thank goodness. 8.7 magnitude...geez, that's just a hair away from December's 9.0 quake.

its epicenter was 155 miles south-southeast of Banda Aceh, the capital of Aceh province on Sumatra island.

Hundreds of buildings (homes and businesses) destroyed.

The poor folks at least are taking the extra precaution of running for higher ground, in case of tsunami.

Two nasty aftershocks so far: 6.0 and 6.7.

--Cindy

P.S.: Actually this quake did produce a small tsunami:

The only tsunami reported was a tiny one — 10 inches — at the Cocos Islands, 1,400 miles west of Australia. No damage was reported.

::EDIT:: http://story.news.yahoo.com/news?tmpl=s … uake]Death toll from this most recent quake may reach 2,000

Trebuchet · 2005-03-28 19:26:34

Hmm, last quake is the day after Christmas, this quake is the day after Easter...

OK, who's pissing God off?

Palomar · 2005-03-29 06:17:50

Hmm, last quake is the day after Christmas, this quake is the day after Easter...
OK, who's pissing God off?

*Good grief, I didn't see that Grypd had posted the news before I did. Sorry! (Yesterday was...never mind)

Treb, I just hope for their sake of course that another earthquake doesn't strike. But for OUR sake I hope one (especially of a high magnitude) doesn't occur on the 4th of July, or the 5th. Those rumors that perhaps the U.S. is planting bombs on the ocean floor and detonating them to get at the Muslims population would start up again. :-\

--Cindy

SpaceNut · 2005-03-29 06:44:20

Sure seems like the ring of fire is very active, in that we have had several volcanoes go active here an in russia as well as a few quakes. What's next, Hawaii blowing its top... Just sort of seems odd all this activity.

SpaceNut · 2005-03-29 13:28:56

This is good news if accuracy can be proven:
Some Deep-Sea Earthquakes Send Out Early-Warning Signals, Seismologists Say

Earthquakes along a set of fault lines in the Pacific Ocean emit small "foreshocks" that can be used to forecast the main tremor, according to research in the March 24 issue of Nature.
It is the first demonstration that some types of large imminent earthquakes may be systematically predictable on time scales of hours or less.
Statistically reliable forecasting of imminent quakes has been an elusive goal for seismologists.

For the purposes of the study, the researchers defined a foreshock as any tremor of at least 2.5 magnitude on the Richter scale. Earthquakes were tremors of no less than 5.4 magnitude.
The researchers then declared a hypothetical "alarm" for an hour within a 15-kilometer radius of the epicenter of every foreshock.
This retroactive and "naïve" early-warning system would have predicted six of the nine major earthquakes that occurred along the two faults between 1996 and 2001, researchers said.

I guess a lot depends on the number of sensors and existing data to be used to fine tune any prodictions for a coming event.

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Re: Tsunami in Asia

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