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Tsunami Disaster.....avoidable?

Posted by Vgkg (My Page) on
Wed, Dec 29, 04 at 11:07

What's wrong with this picture? A massive undersea earthquake occurs and due to a world-wide network of seismographs it's location is immediately pinpointed undersea and rated as immense. Now any low-level geologist or seismograph intern who monitors these events would surely know that large undersea earthquakes have a great potential to cause tsunamis. It took 2 hours for the wave to reach Sri Lanka after the quake occurred. The excuse being used is that there are no tsunami monitoring stations/buoys out in the Indian ocean. Is that really necessary to post a tsunami warning???? I bet that within an hour CNN was broadcasting the news around the world about the massive quake but not a word about a possible tidal wave. Someone dropped the ball Big-time and I'm betting that those in charge did not want to be responsible for causing a panic if no wave showed up....or perhaps I'm just a crusty ol' cynic...


Follow-Up Postings:

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RE: Tsunami Disaster.....avoidable?

No, there is no tsunami alert system in place in the regions affected. Heck, who in the region would have the multilingual capabilities of sounding alarms and who among the locals would or could respond immediately? Second, the USGS first rated the earthquake at around 8.0, not 9.0 which is 100 times stronger on this logrithmic scale.

But you are right about locals not wishing to upset the local economies. The Indonesian authorities refused to alert coastal communities because local tourist season would be destroyed. Same with Thailand.

I live in a very earthquake-prone area, one devastated on a regular basis (every 50-60 years) but one experiencing hundreds of quakes a year. Besides earthquakes, we live with possible collapses of oversteepened marine sediments on the slopes of vast and deep submarine canyons. Major quakes of landslips in these marine waters would give us little time to evacuate settlement on coast plains. We would have a better chance of such evacuations than those folks living in the areas recently hit by the tsunamis.


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RE: Tsunami Disaster.....avoidable?

Predicting tsunamis is not an exact science. Sort of like predicting earthquakes. You almost never, let me clarify that, never hear of earthquake predictions.

In the case of tsunamis, they simply know that it is possible, but not with any degree of certainty of where or when any would strike. There are a range of sensors in the Pacific which will warn people of tsunamis because they can be tracked. In a way, I do not blame the Indonesian, Thai, Indian, and other governments about not posting warnings. However, it may have been prudent to at least post some type of an advisory to give people a chance. There are probably over 100,000 dead from this and at least that amount are expected to be killed in the aftermath from disease and the lack of potable water.

I guess after this tragedy, the countries in the area will cooperate on a tsunami warning system similar to the one in the Pacific Ocean. It is a tragedy that it took such a catastrophic cost to get one started. But hopefully that is one lesson that would be learned from this.


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RE: Tsunami Disaster.....avoidable?

Yes I realize that there are no "tsunami alert systems" in place across the vast areas affected, but there is instant comunications nowadays. If isolated villages could not be warned then at least some of the more populated coastside towns and resorts could have gotten the word in time. By "the word" I mean satellite, cable, radio, and even cell phones. If I were vacationing at one of the beach front resorts and saw CNN report the undersea quake it would have been helpful to at least have them report a tsunami watch to add to the report. Folks may have been more inclined to go shopping inland that day instead of going down to the beach.

My real point is that those in-the-know about how undersea quakes work must have at least thought of the possibility of a tsunami but decided not to bring it up? Confirmation of a tidal wave should not be a factor (via ocean based instruments) and the potential should have been reported to CNN (and others) who aired the quake story.

As far as quake ratings are concerned, 7, 8, 9 it doesn't matter, any of these can trigger underwater landslides, it depends on the lower threshold of the seamount.
BTW, 8 vs 9 - shouldn't that be a factor of 10?

vgkg (who always has this in the back of his head when sitting on the beach at Cape Hatteras)

Here is a link that might be useful: East Coast possibilities


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RE: Tsunami Disaster.....avoidable or not?

ADR,
I guess after this tragedy, the countries in the area will cooperate on a tsunami warning system similar to the one in the Pacific Ocean

I surely hope they DON'T wait for a system to be set up. If another seaquake hits tomorrow all the news outlets should report the tsunami possibility ASAP. Many won't hear it but many will.

Confusion say : "If someone fires a gun at you, don't assume he's shooting blanks"


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RE: Tsunami Disaster.....avoidable?

A 9 quake is 10 times that of a 8 quake A 9 quake is 100 time that of a 7 1000 times that of a 6 10,000 times that of a 5.....

Why are we looking for someone to blame?

Everything is AVOIDABLE after the fact.....


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RE: Tsunami Disaster.....avoidable?

Vgkg, just because there is an earthquake, it does not automatically equate to a tsunami. There has to be displacement of water. Otherwise you get may get some waves, but not a tsunami. The earthquake in Indonesia displaced enough water to lower the ocean levels of the Pacific in California by a foot (of course we know that now).

Other major quakes may not displace water and therefore may not cause tsunamis. I know it is a fine line between warning people of a possible tsunami or an impending tsunami. I don't know where to draw the line myself.

You know about the boy who cried wolf. At what point do you start to lose credibility and your warnings mean less and less. That is for others to decide.


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RE: Tsunami Disaster.....avoidable?

The largest problem with any tsunami warning system is the ignorance of the general population. This would be especially true in a third world area with poorly educated populations. Many would have no idea even what a tsunami is, how to responde, or how dire the threat actually would be for them. Even some of the people I saw interviewed on the news from developed countries appeared ignorant of what a tsunami is or what can cause them. Also, tsunami is a Japanese word meaning harbor wave and probably would not be understood or interpreted correctly by many people. We are at an advantage here with a relatively pervasive common language that makes dispersal of warnings much simpler and more effective. At least 10 countries were involved in this disaster and each with its own language and probably several dialects as well.

I understand your concern with why the detection of the earthquake by scientists couldn't have been more effectively converted to a tsunami warning, but even the seismic waves take time to travel through the Earth. It is likely that by the time the detectors in Europe and North America and other centers of earthquake study detected the earthquake and had time to determine the exact location of the epicenter that many of the immediate areas had already be hit by a tsunami.


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RE: Tsunami Disaster.....avoidable?

AzDesertRat is correct about the lack of a concrete relationship between earthquake location and magnitude and the potential for a tsunami. Of the two, location has a greater relationship than magnitude. The vast majority of earthquakes that occur offshore are along strike-slip faults related to rift zones. Some of these can be very powerful and destructive as we know from the San Andreas fault. Strike-slip faults don't result in the large vertical displacements of the Earth needed to create a tsunami. Movement is lateral instead. The type of faults that produce vertical displacement are called reverse and normal faults.

Of these two, reverse faults which are caused by compressive stress, are the type associated with earthquakes at continental plate subduction zones such as the one that caused the Indonesian earthquake. Great amounts of energy can be stored in rock under compressive stress because rock is much stronger in compression.

Normal faulting occurs in states of tension and rock has little mechanical strength in tension so energy storage is normally much smaller. Normal faulting is common within rift zones where continental plates are pulled apart.

All that said, all types of faults and their associated earthquakes can cause offshore landslides due to the seismic energy released into unstable land masses. These landslides can also create a tsunami indirectly.


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RE: Tsunami Disaster.....avoidable?

Alright...."Uncle"!
Perhaps I'm being a bit rough. I'm not looking for someone to Blame, just can't fiqure out why "tsunami" or "tidal wave" didn't POP into the experts heads instantly, or perhaps it did? As soon as I heard the words "powerful undersea earthquake" on CNN it was "tidal wave" that popped into my little head. A later broadcast announced the tsunami. Wolf! Wolf!
vgkg (who hopes for the best but prepares for the worst)


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RE: Tsunami Disaster.....avoidable?

In one article I read, a witness to the disaster in India said a friend phoned him from Switzerland to alert him to the eathquake and possible tsunami to follow. My feeling is, if there was even the possibility, warnings or advisorys should have been given. At least some of the places affected have warning systems in place to alert the population of hurricanes & such.

This is interesting. I've heard animals can sense an impending earthquake.
_____

Published on Wednesday, December 29, 2004 by the Associated Press
Did Animals Sense Tsunami?

Rescuers look for survivors at Yala Reserve Wildlife Park, 200 kilometers (125 miles) southeast of Colombo, Sri Lanka, Wednesday, Dec. 29, 2004. Wild life officials expressed surprise Wednesday that they found no evidence of large-scale animal deaths from the weekend's massive tsunami, indicating that animals may have sensed the wave coming and fled to higher ground. (AP Photo/Gemunu Amarasinghe)
COLOMBO, SRI LANKA -- Wildlife officials in Sri Lanka expressed surprise Wednesday that they found no evidence of large-scale animal deaths from the tsunamis, indicating that animals may have sensed the wave coming and fled to higher ground.

An Associated Press photographer who flew over Sri Lanka's Yala National Park in an air force helicopter saw abundant wildlife, including elephants, buffalo, deer, and not a single animal corpse.

Floodwaters from Sunday's tsunami swept into the park, uprooting trees and toppling cars onto their roofs -- one red car even ended up on top of a huge tree -- but the animals apparently were not harmed and may have sought out high ground, said Gehan de Silva Wijeyeratne, whose Jetwing Eco Holidays ran a hotel in the park.

"This is very interesting. I am finding bodies of humans, but I have yet to see a dead animal," said Wijeyeratne, whose hotel in the park was destroyed.

"Maybe what we think is true, that animals have a sixth sense," Wijeyeratne said.

Yala, Sri Lanka's largest wildlife reserve, is home to 200 Asian Elephants, crocodile, wild boar, water buffalo and gray langur monkeys. The park also has Asia's highest concentration of leopards. The Yala reserve covers 391 square miles, but only 56 square miles are open to tourists.

The human death toll in Sri Lanka surpassed 21,000. Forty foreigners were among 200 people in Yala who were killed.

© Copyright 2004 Associated Press
_____


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RE: Tsunami Disaster.....avoidable?

Vgkg, I understand your point. However, without early warning systems set up, it is almost impossible to predict an impending tsunami.

I understand India is now setting up an early warning system for tsunamis. Australia and Japan have also have also pledged resources to help India and others set one up also. The only problem is tsunamis are actually rare in the Indian Ocean. The last one to occur was in 1945 and hit Pakistan. Another one hit in 1941 (earthquake). The one before that was in 1883 from the volcanic erruption of Krakatoa.

Not very frequent events to say the least. Probably why there wasn't an urgent need for one. Given the high population densities in the region, it may have been prudent to get a system set up. However, the infrequency of the events and the lack of resources in the area (ie money) sort of put them on the backburner.

Here is a link that might be useful: More tsunami info


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RE: Tsunami Disaster.....avoidable?

There are news reports all over, on many alternate and mainstream outlets, including CNN, that Thai authorities WERE notified nearly 45 minutes BEFORE the tsunami hit that there had been a massive distrubance. And according to the reports, Thai officials, fearing an impact on tourism, did not broadcast a warning, and have fessed up to it.


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RE: Tsunami Disaster.....avoidable?

We (the world) have universal signs for the toilet; there is no universal run like hell to high ground warning?

That said, I would be in the camp with Althea, I think taking my chance(some warning is better than none) against being trampled(etal)would aford a little more a chance as opposed to tons of water


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RE: Tsunami Disaster.....avoidable?

I have a dumb question was that related to Krakatoa? a little off topic but WE are still washing birds from a totally preventable disaster oil spill!


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RE: Tsunami Disaster.....avoidable?

I also wonder how the massive US defense installations on the islands of Diego Garcia survived the tsunami. They may have been far enough south to avoid the worst.

According to Google:

Diego Garcia is a narrow tropical jungle reef in the Indian Ocean, about 1,000 miles south of the southern India coast. Despite the tropical feel to the reef, this is no Margaritaville. It’s more of a stationary aircraft carrier. Diego Garcia is exclusively a military reservation located on a small host country atoll in the Chagos Archipelago.

Diego Garcia was discovered by Portuguese explorers in the early 1500s. It is the largest of fifty-two islands which form the Chagos Archipelago, located in the heart of the Indian Ocean. The island's name is believed to have come from either the ship's captain or the navigator on that early voyage of discovery.

A tropical footprint-shaped island just 7 degrees south of the equator, Diego Garcia is heavily vegetated. The island covers 6,720 acres in area with a maximum height of 22 feet and an average elevation of four feet above sea level. The shoreline is about 40 miles long and the island encloses a lagoon 6.5 miles wide and 13 miles long.

- - - - - - - - - - - - - - - - - - - - -
Former inhabitant were removed to the Maldive archipelago which was heavily impacted by the latest tsunami.

Here is a link that might be useful: Tsunami risks future of Maldives islands


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RE: Tsunami Disaster.....avoidable?

Sorry sarah, I must have missed something. How exactly is your question related to Krakatoa?

I do understand the oil issue (delaware, I assume), but how it's related to Krakatoa, I haven't a clue.

Jason, most of the authorities were informed of a possible tsunami not an impending tsunami. There is a difference. Again, just because there is an an earthquake does not mean that there will be a tsunami. Again I do understand the hesitation of the authorities, but I agree someone should have said "we MIGHT have a tsunami. Just in case go a little further inland."

It may have saved lives if people chose to heed the warning. Without sensors on buoys and other equipment, it really is impossible to predict a tsunami. Again, another tough choice.


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RE: Tsunami Disaster.....avoidable?

Sarahbn, what significance do a few birds have in comparison to perhaps 100,000 human lives?

I was shocked by the number of stories related by tourists who watched the water recede from shore and had no idea what that might portend. I thought everyone knew what that meant: Head for the hills!!!.

Ryan


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RE: Tsunami Disaster.....avoidable?

Kinda like yellow or green sky before a tornado. Lots of folks don't know.


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RE: Tsunami Disaster.....avoidable?

Sarah, Krakatoa is just to the SE of this seaquake and is on the same "ring of fire" as you can see from the maps below:

Marshall, it does indeed look like DG was in the path of the wave but the NE barrier may have sheilded the rest of the island?

Jason, I saw on MSNBC last nite ("Countdown") the story about the Thailand authorities but they said the intitial 8.6 reading didn't warrant an alert (what the H@ll were they looking for?). There was also another story about Australian authorities trying to warn surrounding governements within the first 30 minutes of the quake but dilplomatic snags slowed down the process.

Monte, I've been trying to find info on just how quickly they can triangulate to determine the location and strength of earthquakes/seaquakes via the worldwide network of sensors but no luck so far....

All indications are that the last land to be hit by the wave was the east coast of Africa (Somalia) which would have given them ~5 hours warning (~3 hours West/beyond Sri Lanka).


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RE: Tsunami Disaster.....avoidable?

I don't think you can blame the victims for not recognizing signs when earth/sea quakes with accompanying tsunamis are so rare. Many of the countries who are participating in the Pacific warning system have signed on after a suffciently damaging tsunami occured. There is a good precedent now for establishing a warning/advisory system in the Indian Ocean.


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RE: Tsunami Disaster.....avoidable?

An interview of a USGS rep I listened to said they knew of the quake almost instantly but it took an hour for them to calculate the epicenter.


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video from Thailand

Video from Thailand as the water came in. Takes a moment to load.


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And there is a blog (of course)

SEA-EAT blog has contact information and related links.


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RE: Tsunami Disaster.....avoidable!?

AZDR, I forgot to thank you for that site, thanks!
Thank's too Bill for the "1 hour" USGS info.
Althea, maybe i missed it but where did someone blame the victims?


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RE: Tsunami Disaster.....avoidable?

Vgkg, maybe I'm a little overly critical. Going back to

1) Monte: "The largest problem with any tsunami warning system is the ignorance of the general population. ..."

2) SoCal: "I was shocked by the number of stories related by tourists who watched the water recede from shore and had no idea what that might portend. I thought everyone knew what that meant: Head for the hills!!!."

(I wouldnt have known what the receding water meant.)

Followed by

3) Bill: "Kinda like yellow or green sky before a tornado. Lots of folks don't know."

I read these posts as meaning that the victims were in some way responsible because of their lack of knowlegde of earthquakes. I don't mean to offend any of the poeople I quoted. Inquiries of that nature have been posed by many others.


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RE: Tsunami Disaster.....avoidable?

I see Althea.
I for one cannot picture ignorance as a source for blame and those statements above didn't strike me as blame. If any blame can be placed it should be directed at those authorities involved who were not ignorant but knew of the potential and failed to act upon it. I suppose there is a "fog of disaster" element here to be considered also.


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RE: Tsunami Disaster.....avoidable?

Thank -you for the picture of the map. I am sorry about being off topic. Sarah


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RE: Tsunami Disaster.....avoidable?

You know these things now Althea. :)

There is not a lot people can do with signs of impending doom. Kinda like the headlights of the truck moments before it crashes into you. Once you see the signs you have to act quickly. Perhaps if someone understood the meaning of receding water they might have had enough time to move a mile inland. If they didn't hesitate. If they didn't lose time warning others. If they didn't dally getting their children. If they had a means of immediate rapid escape.

If I were on the beach and saw the water recede suddenly, I would know it's checkout time from the Earth Motel. There is no way I could run a mile. There is no way I would abandon my wife on the beach who also could not run a mile. I would make haste for the closest path off the beach. Hopefully we could get to our car, get down the road, and get out of Dodge. Cross our fingers. Maybe. Perhaps.

Bill
who has been through yellow sky a few times and the last one shifted the roof on the masonry building a foot dropping all the ceiling lights on the floor, then the gas main broke, then flames shot out 4 feet or so from the pipe catching the wall on fire, then the rain came controlling the fire, then my co-worker and I got a wrench on the pipe to turn it off, then we sat for hours in my truck since his had been crushed by a tree. And the roads home had been blocked by other trees. It all happened in about 15 minutes ("hey, the radio says we might get a tornado" - "hey, look at the sky ... SH*T, GET DOWN" boom thump crash bang thump thump thump roar roar roar roar etc etc etc heart beat jumps up to about 250 as I dive for a doorway)


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RE: Tsunami Disaster.....avoidable?

I am amazed by the some company's efforts to get help for the victims. If you go to Apple and Amazon home pages, the only thing you will find is a link for assistance to the victims. Nothing about sales or products. Sort of refreshing.

Ryan, when I lived down in Playa Del Rey, I told friends that if I ever saw or heard that that Santa Monica Bay was receding, I was driving inland as fast as I could. Most of them didn't know why. Blame it on a lack of education or ignorance of the general populace. Pick it. I can't see many others who don't live near an ocean or an earthquake prone area to know what that means either. Sort of a Kansan trying to deal with an earthquake and a Californian dealing with a tornado (no offense to either).

Bottom line, no one is to blame for the quake, and you really can't blame too many people now for the lack of a tsunami warning. We don't even have an early warning system on on the eastern seaboard. If a tsunami hit somewhere on the east coast, I don't want to even imagine the toll it would take here.

And in sadder news, the death toll is up near 116,000.


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RE: Tsunami Disaster.....avoidable?

FYI from CNN.

"Indian state issues tsunami alert

Thursday, December 30, 2004 Posted: 1:24 AM EST (0624 GMT)

NEW DELHI, India (Reuters) -- The state government in India's Tamil Nadu state, one of the areas hardest hit by Sunday's Indian Ocean tsunami, issued a tsunami alert on Thursday and warned people to leave coastal areas.

Police said aftershocks in the Andaman and Nicobar islands, near the centre of the huge earthquake that caused Sunday's tsunami, were "likely" to cause high waves.

Witnesses said police sirens were blaring on beaches in Tamil Nadu and residents were running away.

The death toll in India is more than 10,000, out of a total figure of more than 80,000 people, more than half of whom died in Indonesia's Aceh province."


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RE: Tsunami Disaster.....avoidable?

VgKg,

I did some quick research on the seismic velocity of the P and S waves that propogate from the epicenter and found the following:

P waves (compressional waves) travel at a velocity between 1.5 and 8.0 kilometers per second through the Earth's crust. Compressional waves result in a back and forth motion in the direction of the waves travel. An example can be made by stretching a Slinky and then releasing a small clump of compressed coils from one end. The area of compressed coils will travel along the stretched slinky much a a P wave travels through the Earth.

S waves (Shear waves) travel at a velocity between 60 and 70% of the P wave velocity or about 1.0 to 5.0 meters per second through the Earth's crust. Shear waves result in a side to side motion at 90 degrees to the direction of the waves travel. An example of a shear wave is the hump that can be made to propogate along a stretched rope if one end is suddenly moved up and down.

Both of these wave types are used to locate the epicenter of an earthquake. Since the velocity of both the P and S waves vary in rock, but have a relatively constant relationship to each other, the arrival times for the P ans S waves will get farther apart at a predictable rate. The further the epicenter is from the recorder, the greater the arrival time separation.

Since both waves are required, the arrival of the slower S wave is necessary before any calculation can begin. Using the fastest estimated velocity for the S wave, it would take about an hour for the S wave to reach the USA from the other side of the world where the earthquake occurred. Using the slower estimated S wave velocity, it could be as long as 5 hours.

For any kind of useful warning, the detectors that located the epicenter would have to be much closer and I suspect those that first reported the earthquakes location were.

It requires calculations from a minimum of three different recorders to pinpoint the location of the epicenter. The arrival of the S wave at the most distant of the three locations would determine the absolute minimum time to determine the earthquake location. This does not include calculation and error checking time, let alone the time required to transmit the information to the necessary authorities.

Each detector location generates a locus of possible earthquake locations forming a circle with a radius equal to their calculated distance to the earthquake. The epicenter will be located at the common intersection of at least three different location's circles. Also, the farther away from the epicenter, the greater the potential for error in the calculation due to the uncertainty in the seismic velocity of the P and S waves.


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RE: Tsunami Disaster.....avoidable?

Thanks Monte, I appreciate that research! thought for certain these events could be computed much quicker by assuming that shock waves traveled much faster...and you know what they say about assume...but in this case one vowel is left out = assme.

Bill, I hear ya. That's why I say if I were watching CNN while at Cape Hatteras and they reported an earthquake anywhere on the floor of the Atlantic - you'd only see me as a blurrr..

At my work place we just recieved this notice below, hopefully it's only precautionary and will not come to light :

"The terrible disaster affecting southeast Asia will certainly create
a number of public health challenges in the immediately affected
areas. However, there is the possibility that these events may lead
to a much larger pandemic influenza problem. The relief effort has
brought a number of people from around the globe to a region not only
affected by the tsunami but also affected by avian influenza. It is
possible that the [local] population in the area might have some
innate immunity due to repeated exposure to avian influenza. However,
with the influx of immune-naive foreign aid workers, there seems to
be a potential for spread into people who may be much more
susceptible. It is a safe assumption that hygienic conditions in the
area are going to be lacking for some time. In addition, many of
these workers might almost suspect that they will come down with an
illness because of the circumstances, and may simply shrug off the
1st signs and symptoms. As they return to their countries of origin,
they may unwittingly depart during the prodromal phase of illness
only to act as the index cases of pandemic flu in their countries.

It would be prudent for federal, state, and provincial public health
departments to set up surveillance systems to monitor the health of
individuals who traveled to help with the tsunami recovery efforts."


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RE: Tsunami Disaster.....avoidable?

Vgkg,

For areas with substantial earthquake detection systems in place, such as in southern California in the vicinity of the San Andreas strike-slip fault system, location of a fault can be determined much more quickly due to the close proximity of the detectors, number of detector locations, and the type of detector.

The most common type of seismograph is simply a glorified high mass pendulum set into the bedrock. This type of detector, unfortunately, lacks the ability to determine the travel direction of the P and S waves, just the amplitude and arrival time. They are however, very effective in that manner.

In some areas, arrays of accelerometers set in the bedrock are used to detect the shock waves produced by an earthquake event, in place of the conventional seismograph. An array of three accelerometers, each one oriented in one of the three normal spatial coordinate directions (X,Y,Z), can detect the direction and distance to the event if sufficiently accurate rock property data is available in the area of the sensors. This type of detailed data is only feasible when the detection area is relatively small. As the detection area gets larger, the number of possible travel paths induces too much error.

As each type of wave arrives at the accelerometer array, the wave's energy imparts an acceleration component to each accelerometer in relation to the orientation of the accelerometer and the direction of the wave's travel.

As an example, if the P and S waves happen to be travelling in the X direction, the P wave would impart all its accelation in that direction while the S wave would impart all its energy to either the Y and Z accelerometers or proportionally to both. Magnitude of the earthquake is determined, in a similar manner as with the conventional seismograph, by measuring the amplitude of the waves.

The mathematics involved in analyzing the accelerometer data, in this case, would determine the direction vector to be parallel to the orientation of the X accelerometer and the arrival times of the P and S waves would produce the distance along that vector to the location of the event. The math will also allow the determination of direction for any other directions of arrival as well. Hence, one device can produce the location of the event and the magnitude. However, information from devices at other locations would provide more confidence in the results.

Variants of this same technology are used in my trade to determine an induced fracture's location and orientation during hydraulic fracturing stimulation of oil and gas wells. However, as I mentioned, the use of accelerometers has limited area coverage due to errors induced by the inhomogenous and anisotropic nature of most rock formations.


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RE: Tsunami Disaster.....avoidable?

Interesting Monte, that may explain why (from the news report I heard last nite) the Australian authorities tried to alert surrounding nations about a potential tidal wave within an hour after the seaquake hit?
Shax! what's the newz on your end? Anything to add? vgkg


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RE: Tsunami Disaster.....avoidable?

Thanks for the info Monte. However, because of all of the seismic activity in the Pacific "Ring of Fire" basin, there should be quite a few sensors in the area. Although it may take 5 hours to reach the US mainland, it should be much less to reach other stations in Japan, Taiwan, and other monitoring stations in the area. They should have been able to pinpoint the quake within a much shorter timespan, within a half hour at most I would guess.

After rereading your post, I got this notion. It seems to make sense. Predicting a tsunami, that's another animal.


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RE: Tsunami Disaster.....avoidable?

Althea,

have you never been surprised by the ignorance of people? My statement should in no way be constued to mean that I "blame" the victims. I realized after I made the statement (and my wife read over the post just now and told me that she didn't know that either-mea maxima culpa) that my interest in such phenomena prompted me to learn something about it. My wife has sat with me and watched some of the same programs on Discovery (when we still had cable and/or satellite) but never picked up on that. I caught on when listening to a children's story about a tsunami when I was 7 or 8. Even when exposed to information, we don't necessarily absorb it if we are not interested, or don't recognize the significance of that information. Now you can be surprised at my ignorance of that basic concept (I know I've heard that somewhere before but never had it brought home to me like that).

Ryan


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RE: Tsunami Disaster.....avoidable?

AzDesertRat,

I suspect that it was first detected and reported by seismograph stations in the areas you mentioned. As you stated, the area should have several seismograph stations due to the "ring of fire" proximaty. I suspect the main delay in making the call to the authorities is due to the analysis and error checking. Add to that, the problems with dispersing the information in a third-world nation and previously mentioned language and govermental bureacracy problems and I don't find it as surprising as some that a delay occurred.

Another problem with the automatic determination of an impending tsunami in this particular case and sending a warning may have been the relative proximity of the fault's location to a land mass. There may have initially been some uncertainty of whether the earthquake actually occurred under the sea or on land. A land based earthquake would not have initially generated any concern of a tsunami. That would be some of the error checking that could be done to confirm the accurate location of the earthquake as more locations reported the event, but that would take more time.


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RE: Tsunami Disaster.....avoidable?

This is the sequence of events reported in India Express.

"Govt got wind 1 hr before waves hit Chennai
Disconnect between agencies: Met runs late, guess where first alert mistakenly sent?

Posted online: Thursday, December 30, 2004 at 0221 hours IST

NEW DELHI, DECEMBER 29: At 7.50 am on Black Sunday, more than one full hour before the tidal waves hit the Tamil Nadu coast, the top brass of the Indian Air Force knew that the Car Nicobar Air Base had been inundated.

But it was only 41 minutes later—during which time the waves were heading west—that the first communique went out from the Indian Meteorological Department (IMD) to the Government. And the Crisis Management Group, the Government’s nodal emergency response unit, met at 1 pm by when the tsunami had come, killed and gone.

And guess who got this first IMD communique? It was sent at 8.54 am to the residence of Murli Manohar Joshi, former Science and Technology Minister rather than his successor Kapil Sibal.

It’s always easier to find faults with the benefit of hindsight—especially in an unprecedented disaster like this one—but an investigation of the sequence of events after the quake hit Sumatra at 6.29 am shows a glaring disconnect between different agencies of the Government. And highlights how precious time—that could have been used to issue warnings and maybe save some lives—was lost.

Consider the sequence of events:

• ‘‘At 7.30 am, we were informed by our Chennai unit that coordinates the logistics for the Car Nicobar base about a massive earthquake near Andamans and Nicobar,’’ Air Chief S Krishnaswamy told The Indian Express today.

‘‘But communication links went down in the Island Territories, the Chennai unit could only raise Car Nicobar base on the high frequency set at 7.50 am ... the last message from Car Nicobar base was that the island is sinking and there is water all over.’’

• At 8.15 am, the Air Chief says, he asked his Assistant Chief of Air Staff (Operations) to alert the Defence Ministry.

Now cut to the civilian establishment.

• Unaware of its fax goof-up, the IMD, as per routine, sent another fax to the Disaster Control Room in the Ministry of Home Affairs (MHA) at 9.14 am.

• Eight minutes later, Cabinet Secretary B K Chaturvedi’s private secretary was also brought into the loop.

• At 10.30, the director of the Control Room T. Swami informed Cabinet Secretariat officials.

• By then the tsunami had hit the Chennai coastline and another earthquake measuring 7.3 struck 60 miles west of Indira Point at 9.53 am.

What happened between 6.29 am and 8.56 am in the IMD is also telling: it shows how the country’s premier met agency works in isolation during an unprecedented emergency.

So even as IMD stations in Chennai, Vishakhapatnam and Kolkata began started receiving after-shock signals within minutes of the main earthquake, and while the rest of the world had already issued the exact epicentre of the earthquake—and the Pacific warning system had sounded a tidal wave alert—the IMD was doing its own calculations to find out the magnitude and epicentre of the earthquake.

Not helping the IMD was the fact that the Andaman station in Port Blair runs on an old, analog system rather than a digital one. In other words, in the event of a large earthquake and frequent after-shocks, what it registered was a ‘‘clipped seismograph’’ —a blank sheet of paper instead of zig-zag lines.

This is exactly what happened.

‘‘For computing the exact epicentre, we need data from three stations in three directions. With Andamans out of operations, it took us longer than expected,’’ explained the duty officer.

By then, the after-shocks had begun at Andamans. The first one was at 7:19 am of magnitude 5.9 on the richter scale. It is not clear whether that was enough to sound the warning bells.

‘‘Tsunamis are never recorded in Indian history, so it did not occur to us,’’ said R S Dattatrayam, director seismology at IMD, who arrived after 8.30 am to the station after being informed. ‘‘I don’t recall the exact sequence of events.’’"


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RE: Tsunami Disaster.....avoidable?

Just read where the executive director for GreenPeace and director Tony Juniper of the Friends of the Earth have called on people to head the warning of this tsunami as further evidence of the hazards of global warming and more similar weather related disasters.

Huh! What planet did these idiots come from? Just more reasons for intelligent people to question the motives of these extremist environmental organizations when their leaders are this stupid. This has got to go down as the most moronic statements I have seen to date from these organizations. Frontal lobotomies must be part of the initiation into environmental organization management.

This tsunami is not related to global warming in any way and it is unlikely that any tsunami would have such a link. The plate tectonics responsible for the earthquake that spawned this tsunami can, over long periods of time, change climate, but the reverse is patently false.

Here is a link that might be useful: Evidence of Idiocy


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RE: Tsunami Disaster.....avoidable?

Any idiot can take a quote out of context and attempt to convince us it means something it was never intended to mean. That "news" link certainly has their fair share of idiots on their staff. This is the source of their outrageous opinion piece.

""2004: The year of living dangerously
This year has seen a succession of ferocious natural disasters, destroying cities and killing tens of thousands of people. Michael McCarthy reports on a trend that is terrifying the insurance industry
27 December 2004

12,300 killed as tsunami sweeps across Asia

Simon Calder: Disaster reveals the reality of these seductive idyllsindependent portfolio

Today's stories in full

The deadly sea surges that swept across southern Asia yesterday, destroying whole communities across at least eight countries, were triggered by the strongest earthquake the world has witnessed for 40 years.

The quake which swelled under the sea near Aceh in north Indonesia created a wall of water that sped across thousands of miles to leave whole towns in tatters and a ghastly death toll.

But the latest "freak" disaster features among a number of ferocious natural disasters that the world has seen this year. It was exactly a year ago, on Boxing Day last year, that the ancient city of Bam in Iran was destroyed by a powerful earthquake that killed more than 43,000 people, injured 20,000 and left 60,000 destitute.

And 2004 has been the year of the hundred billion dollar damage bill - when the weather broke all records.

Across the planet, the violence of the world's wind and rain caused unprecedented economic damage, new figures reveal - adding to fears that the disastrous consequences of climate change are beginning to take effect.

Losses caused by natural disasters, most of them climate-related and headed by hurricanes in America and typhoons in Japan, leapt for the first time to more than $100bn (£52bn), according to preliminary estimates from the Zurich-based reinsurance giant Swiss Re. The remarkable sum will intensify the global warming debate, as more extreme weather events, including tropical storms of greater intensity, are among the predicted consequences of climate change. The astonishing storms of the past year are consistent with this, although scientists say it is not yet possible to link them to global warming directly.

However, leading environmentalists said they should be very much taken as a warning. "Here again are yet more events in the real world that are consistent with climate change predictions based on the most up-to-date scientific models," said Tony Juniper, the director of Friends of the Earth. "Only last year, the members of the United Nations Environment Programme's finance initiative were estimating that insured losses due to natural disasters would soon approach $150bn per decade.

"These figures say we are well on the way to reaching that in just one year. The insurance industry must now add its voice to those calling for urgent action to limit the danger posed by rapid climate change."

Stephen Tindale, the executive director of Greenpeace UK, said: "No one can ignore the relentless increase in extreme weather events and so-called natural disasters, which in reality are no more natural than a plastic Christmas tree.""

Note that Juniper & Tindale are talking about extreme weather events in general & not the tsunami.

Here is a link that might be useful: independent


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RE: Tsunami Disaster.....avoidable?

I think he's form the planet Juniper Monte!
It's a stretch but he may be implying that the rising sea level due to GW makes these "events" even worse? (from original quote). Besides, everybody knows that the biggest threat from GW is that it causes Fox newz to get a bit steamed ;o)


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RE: Tsunami Disaster.....avoidable?

No one can ignore the relentless increase in extreme weather events and so-called natural disasters, which in reality are no more natural than a plastic Christmas tree."

Just how to you interpret this statement any differently than that the author of the statement considered the "so-called natural disasters" as unnatural. To me, unnatural means man-made or influenced by man's actions. The author's use of the term "no more natural than a man-made Christmas Tree" to describe the events indicates t me that he believes they were promulgated by the actions of man, and in this case, in the context of the Independent article, man's impact on global warming. I construe that to mean he felt the tsunami mentioned in the article had at least some unnatural causes.

The guy appears to be nothing more than a glorified lobbyist who apparently has little or no understanding of the issue he is promoting, a position typical of many lobbyists, just an understanding that he gets paid to promote a certain position at all expense. Damn the facts and science, full speed ahead.


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RE: Tsunami Disaster.....avoidable?

Thank you Althea. You saved me from doing what you did: Search out the original quotes in the Fox article. It is as I suspected: Out of context, exaggerated, and then turned into a reinforcement against environmentalism. They were preaching to their choir. So much for No Spin. I particularly liked at the end of his piece he did a redirect with the malaria / DDT bit. Put a little frosting on his enviro-hate cake. DDT was not banned world wide. It was banned in the US with some exceptions for health emergencies. Other nations followed our example. But for many nations it was an issue of insect resistance to the pesticide, and microbial resistance to antimalarial drugs. It was economics. There came a point of diminishing returns for their investment in eradication programs where it became pointless to fund projects that no longer worked. And no other pesticide has proven as successful. It was a wonderful molecule in some respects. But people overused it, natural selection came into play, and resistant mosquitoes prevailed. End of story.


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RE: Tsunami Disaster.....avoidable?

Thank you Althea and Bill for treading the same ground that I was about to tread. There is way to much crap put out by both extremes to make their often weak cases. Hate mentality gaining currency, folks. Using quoted statements or phrases out of context is the simplest and most misleading of the methods. Works in politics as long as we the voters accept sloganeering and sound bites as debate of issues.


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RE: Tsunami Disaster.....avoidable?

Agreed Bill & Marshall. The contortionist journalism practiced by Fox is intended to serve as fuel for extremist agendas.

At least two geophyicists believe there is a relationship between global warming and earthquakes in the Arctic region.

Here is a link that might be useful: csmonitor


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RE: Tsunami Disaster.....avoidable?

I have to question the logic about glaciers holding down the number and frequency of earthquakes at the poles. While the glaciers are massive and heavy, I suspect their total mass is small when compared to the crustal plates they ride on where the earthquakes originate. There are well documented undersea earthquakes. I would suspect the pressures from several thousand feet of water would be similar to crustal pressures created by glaciers. Yet undersea earthqaukes occur regularly. Is it the shift of water weight from glacier to open water causing earthquakes? Don't know. Is it an increase in geological activity that coincides with glacial reduction? Don't know. Valid hypothesis? Yes. Fact? I'm not convinced.

****

Returning to Fox News for a moment, do you know what movie continuity is? That's where all the visual elements of the scenes remain consistant. A character's tie stays the same color. Their hair is combed the same. The car does or does not have hubcaps. If a movie fully engages me, I don't notice these things. But if it fails to hold all of my attention and leaves some brain time slices open to process subliminal items, they may actually rise in my conciousness and obscure the movie. I've found myself doing this with talk radio quite a bit. I'll hear a news story and unknowingly park it in memory. Then I'll hear an analysis of the news from Franken, O'Rielly, Limbaugh, et al, and immediately sieze on an "inaccuracy". If only my memory had enough capacity and accuracy. It is fascinating but a little disturbing to realize the facts get massaged by the teller depending on their reaction to the news.


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RE: Tsunami Disaster.....avoidable?

There are still tremors associated with deglaciation of North America, particularly along an axis from Long Island through the Ohio Valley. Icecaps several miles deep had depressed the underlying rock formation so that after the ice melted away and back, the land began and long period of rebound marked by episodes of earth tremors.


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RE: Tsunami Disaster.....avoidable?

While it is true that glacial rebound produces tremors, they are generally minor in magnitude with minimal displacement. The tremors are more often the result of fracturing that occurs as the compressive stress is relieved from the rock. Since most of this excess stress was applied to the rock in the vertical direction, due to the weight of the overlying ice, the fractures are mostly horizontal. They are also usually very shallow because any amount of burial creates a sufficient vertical compressive stress component to prevent the tensile rock failure mode characteristic of these fractures.

This type of seismic activity is much different than the type produced by the elevated horizontal stresses related to tectonic plate movements at subduction trenches or seafloor spreading ridges, continental rift zones, thrust faults, and strike-slip fault zones.


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RE: Tsunami Disaster.....avoidable?

It is fascinating but a little disturbing to realize the facts get massaged by the teller depending on their reaction to the news.

Good point, Bill. Even a word for word replay by another party can change the focus through emphasis on certain words or phrases....with also attendant garnishing. And we all have heard of spin.


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RE: Tsunami Disaster.....avoidable?

Of course (otherwise known as DUH, Dude) I haven't read in detail the statements on geoseismic matters offered by those climatologists (and do-gooding enviros that might have been quoted.) Sinilar incidence of rebound are reported from Scandinavia which is another low-active seismic region. Want to bet that the cited quotes were part of a much more meaningful context even from climatologists?


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RE: Tsunami Disaster.....avoidable?

To get back on topic...as far as early warning systems for such disasters go......

"The Thai Government was officially warned seven years ago that tsunamis stemming from an earthquake on the seabed could hit southwest Thailand, but the warning was ignored for fear of frightening off tourists and investors."

Here is a link that might be useful: Thais Ignore Warnings


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RE: Tsunami Disaster.....avoidable?

At least he was vindicated in his lifetime. Too many who issue warning calls and are subsequently vilified never get the recognition they deserve until after they're gone. Of course, having the disaster occur before your death helps...

Ryan


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RE: Tsunami Disaster.....avoidable?

Sorry, Shaxhome, but this sort of news is a little too breathless. I can predict that a major earthquake will hit California in the next 7 years. Odds are pretty good. I might even predict no major tsunami of local origin with some confidence because our major San Andreas fault is a strike-slip zone. The tectonic plates are slipping past one another as the Pacific plate slides under the North American plate. We do have thousands of other smaller fault lines, some of which are overthrust faults (e.g. Northridge) similar to the megathrust fault off the Indonesian coast but much smaller.

If the warning had been specific (as the Thais seem to be claiming their geologists were), I might accept this FOX News report. :)

Geologists became very concerned about growing seismic activity in that part of the Indonesian archipelago, including a growing bulge in the center of the Krakatoa caldera. An island now exists there. The archipelago is arranged along a major thrust-faulting zone where several continental plates are interacting. There've been a couple of science papers on these matters over the past couple of years. Wish I had paid more attention and book marked them.

Where's Monte?


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RE: Tsunami Disaster.....avoidable?

(giggleing) Like our government never missed opportunities to act on issues of public health and safety.

*** moment of wry sarcasm

Well, at least when the Republicans are done destroying the school system so no one but the upper crust (my sly way of staying on topic) can afford an education, and when they are done shipping all the jobs overseas so we have a lower class similar to SE Asian nations, then we can have natural disasters that kill as many folks in cardboard homes as they do over there. We will finally be able to compete with them on an equal footing in something. Finally.


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RE: Tsunami Disaster.....avoidable?

Of course, there is an overthrust fault in the vicinity of Santa Cruz Island...

Ryan


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RE: Tsunami Disaster.....avoidable?

Sorry for posting that, Marshall...I'll take a deep breath and duck out now....am very glad that you are in control of California's early warning system and are so definite that no harm will befall you and yours...

Science (and guesswork) are wonderful things....and comparable, IMHO...


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RE: Tsunami Disaster.....avoidable?

Shaaaaaax, come baaaaack! I'm sooorrry, so sorry for being an insensitive a$$.


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RE: Tsunami Disaster.....avoidable?

The archipelago is arranged along a major thrust-faulting zone where several continental plates are interacting.

Volcanos like Krakatoa, Mt. St. Helens, Mt. Hood, Mt. Shasta, etc., are the result of the melting of low density rocks that are carried deep into the Earth at subduction zones. As such, they are normally located some distance inland, or equivalent on the overriding landmass, from the subduction zone itself. The low density minerals are carbonates, shales, and sands that have been deposited on the thin basaltic basement rock of the deep seafloor. As the subducting plate dives under the overriding plate, the pressure and temperature these low density mineral are exposed to increases. At some depth, they melt and decompose to form the magma that forms the volcanos. Since the density of this magma is considerably lower than the surrounding rock which is primarily basalt and olivine, they begin to move upward due to bouyancy effects.

Considerable amounts of water vapor, sulfur gases, carbon dioxide are also trapped in the magma as a result of the thermal decomposition of the sedimentary rocks at depth. As the magma rises, these gases, highly pressurized after forming at great depths, begin to expand and create additional forces to break through the overlying crustal rocks. It is the sudden release of these same dissolved gases at surface that produces the violent explosive eruptions such as occurred at Mt. St Helens and Krakatoa.

As this magma forces its way up through the crust, seismic events occur due to the fracturing and failure of the overlying rock. However, these are generally of low magnitude and shallow. This is significantly different then the very deep seated earthquakes and potentially high magnitude earthquakes resulting from slippage between the subducting and overriding plate which may occur several miles underground.

From that perspective, earthquake events associated with these type volcanos probably have quite poor correlation with tsunami events except when the volcano is located in the ocean as is the case with Krakotoa. Even in the case of Krakotoa, it was not the eruption of the volcano or seismic activity that directly caused the tsunami, but the collapse of the volcano to form a huge caldera.


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RE: Tsunami Disaster.....avoidable?

Marshall...I do apologise for my petulance, but I was really most exasperated by your easy dismissal of that story. Which part don't you believe? Was it purely because of its source?

Don't you think that if that early warning system and alarm bells were in place, that at least SOME lives might have been saved? And likewise for keeping resort buildings further from the coastline? And isn't the fact that :

"But last Thursday, Thai Prime Minister Thaksin Shinawatra put Mr Samith in charge of establishing an advanced seismic and tsunami warning system for the whole nation. The brief would also take in other calamities such as storms and floods. He was named a vice-minister reporting directly to Mr Thaksin."

some vindication for his beliefs and efforts?

I do have a personal interest in this matter. My son had been on a surfing holiday in Phuket 3 days before the tsunami struck and I spent a harrowing 24 hours before he contacted me to let me know that he had by that time moved on into the high mountain country....

Regards,

Shax


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RE: Tsunami Disaster.....avoidable?

Oh Shax, what a relief for you that he was safe afterall.

I wasn't deriding the scientists; I was reacting to the blame-gaming going on. Or so it seemed to me. Nearly every major earthquake we've had around here over the past 34 years came as a surprise in that many were associated with unknown or minor fault structures (outside those along the San Andres fault zone.) Several fairly reputable geophysicists or geologists have warned of impending major tremors along monitored faults. We are for the most part still waiting for the high-probability earthquakes.

I go into this detail because California has been extensively studied and monitored for a long time, and we can't predict with any precision when or where a quake will strike; much less predict tsunamis. At least we are part of a buoy system and so will have some warning of approaching tsunamis.

Thailand the other countries around and in the Indian Ocean have a big and costly job to install, staff, and manage a warning system.

Monte, thanks for the detail. I remember reading in college that when Krakatoa blew there was both an immediate tsunami and a later one associated with the caldera collapse, inflow of ocean waters and violent blowback, so to speak.


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RE: Tsunami Disaster.....avoidable?

Tsunami-Generating Earthquake Near U.S. Possibly Imminent
By Robin Lloyd
Special to LiveScience
posted: 03 January 2005
07:21 pm ET
There are only two places in the United States where colliding tectonic plates could cause a major tsunami, and new studies show a new earthquake in at least one of these locations could be imminent.

The Cascadia subduction zone, a 680-mile fault that runs 50 miles off the coast of the Pacific Northwest -- from Cape Mendocino in California to Vancouver Island in southern British Columbia -- has experienced a cluster of four massive earthquakes during the past 1,600 years. Scientists are trying to figure out if it is about to undergo a massive shift one more time before entering a quiescent period.

"People need to know it could happen," said U.S. Geological Survey geologist Brian Atwater.

The historical record for this zone, which has the longest recorded data about its earthquakes of any major fault in the world, shows that earthquakes occur in clusters of up to five events, with an average time interval of 300 years between quakes, said Chris Goldfinger, a marine geologist at Oregon State University. Goldfinger and other scientists have been studying this subduction zone for many years.


At the Cascadia subduction zone, an oceanic tectonic plate called the Juan de Fuca is pulled and driven (subducted) beneath the continental North American plate, setting up conditions for undersea "megathrust" earthquakes

The two most recent quakes on this fault occurred in the year 1700 (a magnitude 9 event) and approximately the year 1500. It has now been 305 years since the last event. So is the Cascadia subduction zone finished for now or on the brink of event number five?

"We know quite a bit about the periodicity of this fault zone and what to expect," he said. "But the key point we don’t know is whether the current cluster of earthquake activity is over yet, or does it have another event left in it."

At the Cascadia subduction zone, an oceanic tectonic plate called the Juan de Fuca is pulled and driven (subducted) beneath the continental North American plate, setting up conditions for undersea "megathrust" earthquakes.

The Cascadia subduction zone occurs where the relatively thin Juan de Fuca plate moves eastward and under the westward-moving North American Plate. When that collision results in a rupture, massive earthquakes occur. The other active subduction zone capable of producing a major earthquake-tsunami sequence is in Alaska, the site of a giant earthquake and subsequent tsunami in 1964.

Scientists say a rupture along the Cascadia fault would cause the sea floor to bounce 20 feet or more, setting off powerful ocean waves relatively close to shore. The first waves could hit coastal communities in 30 minutes or less -- too rapidly for the current warning systems to save lives.
A tsunami along the Atlantic Coast is considered extremely unlikely.

Tsunamis are the result of sudden rises or falls in a section of the earth’s crust under or near the ocean, usually caused by earthquakes, volcanic activity or landslides. Earthquakes at subduction zones (rather than at other types of faults such as thrust faults) produce the highest energy tsunamis, especially when they occur in deep water. The seismic activity displaces sea water, creating a rise or fall in the level of the ocean above. This rise or fall in sea level initiates the formation of a tsunami wave. The wave’s height increases in shallower water.

Geologists can track earthquakes back in time by radiocarbon dating deposits of sand called turbidites, which come from undersea landslides.

Major studies on the Cascadia fault zone have identified 19 to 21 major earthquake events during the past 10,000 years. During at least 17 of these events, the entire fault zone probably ruptured at once, causing an earthquake around magnitude 9 and major tsunamis, such as those which savaged East Asia last week.

The Asian event happened where the India plate was subducted beneath the Burma microplate. It ruptured, for the first time since 1833, along a 600-mile front just about the same length as the Cascadia Subduction Zone.

The Asian event may provide a shocking demonstration of the geologic future of the Pacific Northwest, Goldfinger said. For hundreds of years, subduction zone plates remain locked in place, releasing little tension. Every few centuries, in a few minutes of violence, forces are released as the upper plate moves seaward, producing a massive tsunami following earthquake shaking.

"In the case of the Cascadia Subduction Zone, you could have an area of ocean floor that’s 50 miles wide and 500 to 600 miles long suddenly snap back, causing a huge tsunami," Goldfinger said. "At the same time, we could expect some parts of the upper, or North American, plate to sink one to two meters. These are massive tectonic events. Subduction zones produce the most powerful earthquakes and tsunamis in the world."

The question is not whether, but when the Cascadia Subduction Zone will break again.

"One possibility is that we could be done with this cluster and looking at a period of many hundreds of years before the next earthquake," Goldfinger said. "The other distinct possibility is we could still be in a cluster of events. If that’s the case, the average time interval between earthquakes within a cluster is already up. We would be due just about any day."

The Associated Press contributed to this report


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RE: Tsunami Disaster.....avoidable?

VGKG, where is the other place in the US?


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RE: Tsunami Disaster.....avoidable?

Ha, I think the author is teasing us Marshall. Best guesses are off the Alaskan coast or the mid-Atlantic? That peskie old volcano in the Canary Islands hangs over our heads here in the east. Here's the world map of plates and associated volcanoes.

Trying to google up some info on past Atlantic tidal waves, have to sort thru a lot to get some tidbits like this one below :

"Scientists in Great Britain and the United States have recently released a report that indicates that one of the volcanoes in the Canary Islands in the eastern North Atlantic is particularly unstable, and will, someday, set forth a trans-atlantic tidal wave of mammoth proportions. And although they are cautious to state that there is no immediate danger, the Geological Society of London has already told the government that contingency plans should be developed.

The Canary Islands are a chain of small islands just offshore from Morocco in West Africa. One of the smaller islands, La Palma, is home to the Cumbre Vieja volcano. Of itself, this is not unusual. Many volcanoes, some highly active, exist throughout the globe.

La Palma, however, is one of the steepest islands in the world and is therefore potentially unstable. In addition, Cumbre Vieja is the most active volcano in the Canary Islands, having erupted most recently in 1971. Scientists are concerned that eventually, a major eruption of Cumbre Vieja will result in the collapse of the western face of the island - sending a mountain of earth to the ocean floor and setting forth a tidal wave, or, as they are also called in the Pacific Ocean, a tsunami.

According to modelling results, the tidal wave generated by this eruption would propagate outward from the centre of the eruption at the speed of a jet aircraft - reaching the coast of Africa and Europe within minutes, and impacting Newfoundland in about eight hours. Some model runs indicate that a particularly strong eruption would generate a wave which, even after traversing the Atlantic, would be 25 metres in height upon reaching our coasts.

Studies of this nature are invariably welcomed with a certain degree of caution, perhaps even cynicism. A 25 metre wave? From the other side of the Atlantic? Not likely!

On November 1, 1755, an underwater earthquake in the eastern Atlantic set forth a tidal wave which killed 60,000 people in Lisbon, Portugal. Thousands more were drowned in other areas of Europe and in Africa, in one of the most significant earthquake events in European history.

Tidal waves, or tsunamis, in the Pacific Ocean are relatively common and it is well known that a tsunami generated from an earthquake in a specific area may travel thousands of miles. It is not surprising, then, that the effects of the Lisbon earthquake were felt in Newfoundland. Rev. Philip Tocque, an Anglican minister born in Carbonear, wrote, in his book Wandering Thoughts, about the tidal wave when in hit Bonavista.

"The sea retired and left the bed of the harbour dry for the space of ten minutes, when it again flowed in and rose to an unusual height, overflowing several meadows for about the same space of time as it had retired...the waters on each side of the cape were greatly agitated".

Atlantic Canada has also evidenced a tidal wave within the preceding century. On November 18, 1929, an underwater earthquake precipitated a "landslide" along the Laurentian Continental Slope in waters south of Newfoundland, generating a tsunami which swept along the south coast of the island. The Burin Peninsula Tidal Wave swept away homes, wharves, flakes and everything else in its path. Twenty eight lives were lost in what has been described as Canada's most tragic earthquake.

P. J. Antle was nineteen years old at the time and described the first wave as a "great black monster...the noise of smashing timber, the roar of the sea, the movement of thousands of tons of rocks, the screams of horrified people, all blended into one indescribable crescendo. All the demons in Hell were let loose."

Of course, Pacific Ocean tsunamis are far more frequent than Atlantic Ocean events, and far more devastating. One of the most famous tsunamis resulted after Krakatoa blew itself to pieces in 1883 - a six metre wave killed 36,000 people. Thousands more have been killed in earlier times or during the past century. Most recently, a tsunami killed 2,000 people in Papua New Guinea in 1998.

Although attention throughout history has focussed mostly on Pacific Ocean events, it is clear that our own waters are not without their own dangers. An increased scientific attention to the potential impacts of earthquakes, volcanic eruptions and resultant tsunamis in the North Atlantic is therefore welcome news.

Copyright, November 1, 2001.

Bruce Whiffen.

Here is a link that might be useful: USGS Techonics...


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RE: Tsunami Disaster.....avoidable?

I'm about 875 ft. above sea level. I'm not too concerned about a tsunami here, but when Southern California has her "big one", I don't want to be around, period. That one is prophised to take LA under.


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RE: Tsunami Disaster.....avoidable?

Wayne, I have big doubts about LA/CA falling into the ocean (well, I doubt all prophecies anyways). As you surely know, what you need to worry about (besides Yellowstone blowing up) is your more local threat - The New Madrid Fault. Don't let that 1895 6.8 fool ya, the site below recaps the 1812 8+ magnitudes, 3 of them...

Here is a link that might be useful: The


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RE: Tsunami Disaster.....avoidable?

Having lived in California for several years, I am much more aware of earthquakes than I had been living in other parts of the country and world. I actually felt one here in November 1999 which was a 5+ magnitude earthquake that struck outside of Needles, CA. It actually cracked some of the plaster in pools on the west side of town here.

I remember researching the huge quakes of 1811-1812 and seemed to recall that a lot of the Mississippi River was on a fault line. It is not as active as the fault lines which line the Pacific basin. Because of the increased number of earthquakes, homes on the West Coast are built to withstand most earthquakes; unfortunately, that is not true in other parts of the country. Many of the older homes in the midwest are brick and any rockin and rollin, the homes will collapse on each other. Unless building codes are updated and older buildings are retrofitted, I would fear that there would be a large number of casualties. Hopefully none of us see the day when that happens.

I am not worried about a tsunami here either. I am at 1500' above sea level protected by mountains in California, New Mexico, Colorado, Mexico, as well as the surrounding mountains. If a tsunami makes it here, something much more worse has gone on, and the tsunami is the least of mine or anyone else's worries.

Marshall, Ryan--any thoughts considering both of you are in California?


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RE: Tsunami Disaster.....avoidable?

ADR,

I'm on a coastal plain about 15 miles inland, at an altitude of 30-50 feet. While tsunami have exceeded those heights, I've never heard of one making it so far inland.

Ryan


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RE: Tsunami Disaster.....avoidable?

I am only a few miles from the ocean but am protected by an intervening higher mesa and by living a couple hundred of feet above sea level.

If you study a population distribution maps of the world, you might have noticed that half the population occupies the coastal edges of oceans and inland seas. Those coastlines affected by the latest tsunami basically means the ravaging of about a half million or more people through the direct and indirect effects of the tsunami and aftermath.


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RE: Tsunami Disaster.....avoidable?

You forgot to add Marshall, that the same people live in these areas are also prone to earthquakes and volcanic activity. This includes the Mediterranean basin, almost all of the Pacific Rim, the Northern Atlantic and the Carribbean. In fact, there are very few places that people live which aren't prone to such problems (well maybe here in Arizona).

The point I was trying to make earlier about a huge tsunami was the source of the energy would have to come from a meteorite or a supervolcano blowing its top. Otherwise, most of us would be able to get to safety if we received some type of advanced warning.


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RE: Tsunami Disaster.....avoidable?

Returning to the Fox link for a moment, Grist reports:

**When pressed to name an environmentalist who had claimed a causal link between global warming and the South Asian tsunami, Michaels referenced comments made by Tony Juniper, director of Friends of the Earth U.K., and Stephen Tindale, executive director of Greenpeace U.K., in a Dec. 29 article about the tsunami and other natural disasters of 2004 in the British newspaper The Independent (reprinted in Pretoria News). But, while both environmental leaders were quoted remarking on an increase in natural disasters potentially related to global warming last year, neither mentioned the tsunami. In fact, in a press release put out today, the two groups say their leaders' quotes were given before the tsunami even hit.**

Grist sites others of similar ilk, CATO & Competitive Enterprise Institute who are on the same well worn path as Fox.

Here is a link that might be useful: exploiting the tsunami


 
 

 

 


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