Tsunami and earthquake effects - Tilted Forum Project Discussion Community

jusolson00 · 12-29-2004, 05:00 PM

okay, I'm not sure where to post this, so I'm gonna give this forum a try. Anyways I wanted to shed light on the recent earthquake and resulting tsunami that struck southeast asia. This event is truly tragic and my heart goes out to all who are affected, but this tread is not about the tragic loss of life, but rather the tsunami and earthquake itself and the effects it had.
For instance, I recently heard on the NBC evening news that the earthquake was so powerfull that it actually shifted the earth on its axis, and caused that very day to be shorter than it should have been! Altough I think they said only by hundredths of a second, but still!! i mean isnt this major?? A natural catashtrophe that can shorten the day???!! I am truely in awe. They also reported that part of the island nearby the epicenter (I cant recall the name) suffered a major geolological shift, meaning that land that was once under water is now surfaced and vice versa. I have very little knowlege in these kinds of fields and thought that it would be interesting to hear from poeple here on the TFP who are well versed in these kinds of things.

Halx · 12-29-2004, 05:28 PM

It's simple physics really. Take what you know about waves, water displacement, gravity, the earth's axis, and tectonic plates ... then apply it! I was taught all this stuff in grade school.

In simple terms, the earth's crust (the part that we life on) shifted to where the gravitational pull from the earth's core tightened up a slight bit. Now the earth rotates faster by like .000003 of a second (rough estimate) per rotation.

To demonstrate this in real life, take an object and tie a string to it. Hold the end of the string and swing the object around with a moderate amount of effort. Now, grip the string a little bit closer to the object (essentially shortening the string) and whirl the object around with the same amount of effort. The object will swing faster. In this model, your hand is the core of the earth and the object is any given point on the earth's crust.

Arroe · 12-29-2004, 08:01 PM

halx, I don't think that is right.

I read in an article that even though the quake shifted the Earth very slightly, it did NOT change the length of a day at all because the Earth still spins at the same speed. So there is no need to adjust your clocks.

The way that it was described to me is that the Earth is like one of those top spinner things that looks like a cone that you would spin on a table. The Earth rotates like one of those, the point makes a little circle on the table per say. Now, the quake in Asia moved that just a little bit so the circle is just a tiny bit off now, but it's not a big deal because the amount was so miniscule. So yeah.... time wasn't changed at all. That string thing is incorrect.

Halx · 12-29-2004, 11:07 PM

You gotta make sure of what you're saying. I know I'm sure of what I'm saying. However, I think we both need to come up with some sources.

Rlyss · 12-29-2004, 11:59 PM

I think this is fairly common knowledge but I'll just yap on anyway because it fascinates me.

Before the details started coming through I wondered if an atomic bomb detonated underwater would have a similar effect to this, but if you think about it, thousands of miles of rock underneath the water lifted up between ten and thirty metres. That's a shitload of water, a few thousand miles worth, being lifted above the surface of the ocean, and since it finds its own level it's gotta end up somewhere. So it spreads out and because the water's deep it doesn't really have much of an effect, there's lots of space for the water to go. As it goes closer to land the water gets more shallow and all the force and power in the water is concentrated into a smaller area, causing it to move faster and get taller really quickly. That just blows me away, that you could be fifty miles from the coast and your little boat might just rock gently, but on the beach it turns into a fifty foot high wave.

Zeld2.0 · 12-30-2004, 01:30 AM

Tidal waves in the deep ocean may be felt by few boats at all

The most devastating part comes when it gets close to shallow water (compared to the ocean that is) - most people die when the water recedes and suddenly what was water is now land - in fact, many scuba divers and swimmers suddenly found themselves in shallow water or even on land. But right when so many people run out there, the waves come back and its too late.

Halx · 12-30-2004, 01:30 AM

I think I heard that the entire collected nuclear arsenals of the whole word could not have equalled the amount of energy released in this earthquake.

Pacifier · 12-30-2004, 02:30 AM

one of the earthquakes was a 9.0 as fas as i heard.
that equals the energy of ~30 Gigatons TNT
The largest A-Bomb so far was the russian Tzar Bomb with 50 Megatons

Redlemon · 12-30-2004, 07:35 AM

Quake May Have Made Earth Wobble

Quote:

The deadly Asian earthquake may have permanently accelerated the Earth's rotation -- shortening days by a fraction of a second -- and caused the planet to wobble on its axis, U.S. scientists said on Tuesday.

Richard Gross, a geophysicist with NASA's Jet Propulsion Laboratory in California, theorized that a shift of mass toward the Earth's center during the quake on Sunday caused the planet to spin 3 microseconds, or 3 millionths of a second, faster and to tilt about an inch on its axis.

When one huge tectonic plate beneath the Indian Ocean was forced below the edge of another "it had the effect of making the Earth more compact and spinning faster," Gross said.

Gross said changes predicted by his model probably are too minuscule to be detected by a global positioning satellite network that routinely measures changes in Earth's spin, but said the data may reveal a slight wobble.

The Earth's poles travel a circular path that normally varies by about 33 feet, so an added wobble of an inch is unlikely to cause long-term effects, he said.

"That continual motion is just used to changing," Gross said. "The rotation is not actually that precise. The Earth does slow down and change its rate of rotation."

When those tiny variations accumulate, planetary scientists must add a "leap second" to the end of a year, something that has not been done in many years, Gross said.

Scientists have long theorized that changes on the Earth's surface such as tide and groundwater shifts and weather could affect its spin but they have not had precise measurements to prove it, Caltech seismologist Hiroo Kanamori said.

"Even for a very large event, the effect is very small," Kanamori said. "It's very difficult to change the rotation rate substantially."

12-29-2004, 05:00 PM	#1 (permalink)
jusolson00 Tilted	Tsunami and earthquake effects okay, I'm not sure where to post this, so I'm gonna give this forum a try. Anyways I wanted to shed light on the recent earthquake and resulting tsunami that struck southeast asia. This event is truly tragic and my heart goes out to all who are affected, but this tread is not about the tragic loss of life, but rather the tsunami and earthquake itself and the effects it had. For instance, I recently heard on the NBC evening news that the earthquake was so powerfull that it actually shifted the earth on its axis, and caused that very day to be shorter than it should have been! Altough I think they said only by hundredths of a second, but still!! i mean isnt this major?? A natural catashtrophe that can shorten the day???!! I am truely in awe. They also reported that part of the island nearby the epicenter (I cant recall the name) suffered a major geolological shift, meaning that land that was once under water is now surfaced and vice versa. I have very little knowlege in these kinds of fields and thought that it would be interesting to hear from poeple here on the TFP who are well versed in these kinds of things.

12-29-2004, 05:28 PM	#2 (permalink)
Halx Please touch this. Owner/Admin Location: Manhattan	It's simple physics really. Take what you know about waves, water displacement, gravity, the earth's axis, and tectonic plates ... then apply it! I was taught all this stuff in grade school. In simple terms, the earth's crust (the part that we life on) shifted to where the gravitational pull from the earth's core tightened up a slight bit. Now the earth rotates faster by like .000003 of a second (rough estimate) per rotation. To demonstrate this in real life, take an object and tie a string to it. Hold the end of the string and swing the object around with a moderate amount of effort. Now, grip the string a little bit closer to the object (essentially shortening the string) and whirl the object around with the same amount of effort. The object will swing faster. In this model, your hand is the core of the earth and the object is any given point on the earth's crust. __________________ You have found this post informative. -The Administrator [Don't Feed The Animals]

12-29-2004, 11:07 PM	#4 (permalink)
Halx Please touch this. Owner/Admin Location: Manhattan	You gotta make sure of what you're saying. I know I'm sure of what I'm saying. However, I think we both need to come up with some sources. __________________ You have found this post informative. -The Administrator [Don't Feed The Animals]

12-30-2004, 01:30 AM	#7 (permalink)
Halx Please touch this. Owner/Admin Location: Manhattan	I think I heard that the entire collected nuclear arsenals of the whole word could not have equalled the amount of energy released in this earthquake. __________________ You have found this post informative. -The Administrator [Don't Feed The Animals]

12-30-2004, 02:30 AM	#8 (permalink)
Pacifier undead Location: Duisburg, Germany	one of the earthquakes was a 9.0 as fas as i heard. that equals the energy of ~30 Gigatons TNT The largest A-Bomb so far was the russian Tzar Bomb with 50 Megatons __________________ "It seems to me that the idea of a personal God is an anthropological concept which I cannot take seriously. I also cannot imagine some will or goal outside the human sphere. Science has been charged with undermining morality, but the charge is unjust. A man's ethical behavior should be based effectually on sympathy, education, and social ties and needs; no religious basis is necessary. Man would indeed be in a poor way if he had to be restrained by fear of punishment and hope of reward after death — Albert Einstein

12-29-2004, 08:01 PM	#3 (permalink)
Arroe Insane Location: USA	halx, I don't think that is right. I read in an article that even though the quake shifted the Earth very slightly, it did NOT change the length of a day at all because the Earth still spins at the same speed. So there is no need to adjust your clocks. The way that it was described to me is that the Earth is like one of those top spinner things that looks like a cone that you would spin on a table. The Earth rotates like one of those, the point makes a little circle on the table per say. Now, the quake in Asia moved that just a little bit so the circle is just a tiny bit off now, but it's not a big deal because the amount was so miniscule. So yeah.... time wasn't changed at all. That string thing is incorrect.

12-29-2004, 11:59 PM	#5 (permalink)
Rlyss The Pusher Location: Edinburgh	I think this is fairly common knowledge but I'll just yap on anyway because it fascinates me. Before the details started coming through I wondered if an atomic bomb detonated underwater would have a similar effect to this, but if you think about it, thousands of miles of rock underneath the water lifted up between ten and thirty metres. That's a shitload of water, a few thousand miles worth, being lifted above the surface of the ocean, and since it finds its own level it's gotta end up somewhere. So it spreads out and because the water's deep it doesn't really have much of an effect, there's lots of space for the water to go. As it goes closer to land the water gets more shallow and all the force and power in the water is concentrated into a smaller area, causing it to move faster and get taller really quickly. That just blows me away, that you could be fifty miles from the coast and your little boat might just rock gently, but on the beach it turns into a fifty foot high wave.

12-30-2004, 01:30 AM	#6 (permalink)
Zeld2.0 Cherry-pickin' devil's advocate Location: Los Angeles	Tidal waves in the deep ocean may be felt by few boats at all The most devastating part comes when it gets close to shallow water (compared to the ocean that is) - most people die when the water recedes and suddenly what was water is now land - in fact, many scuba divers and swimmers suddenly found themselves in shallow water or even on land. But right when so many people run out there, the waves come back and its too late.