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Old 03-07-2016, 12:51 AM
Northern Piper Northern Piper is offline
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How long would it take for Titanic to hit the sea-floor?

So the ship gradually fills with water, going down steadily by the bow.

Finally, the stern starts to tip upwards. Then the stern breaks off, and the two pieces of Titanic sink beneath the water.

So how long from the moment the ship disappears beneath the water until it hits the ocean floor?

And, suppose such an accident were to happen today: would the impact of the pieces of Titanic on the ocean floor be enough to show up on modern seismographs?

Last edited by Northern Piper; 03-07-2016 at 12:56 AM.
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Old 03-07-2016, 02:13 AM
blue infinity blue infinity is online now
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Looks like about 5-10 minutes to hit bottom.
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Old 03-07-2016, 07:27 AM
MikeS MikeS is offline
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From that same link, the halves of the ship were travelling at an estimated 30 mph when they hit the bottom. In terms of kinetic energy, each half of the Titanic would have about 2 gigajoules of energy, some fraction of which would be transmitted to the sea-bottom when it impacted.

If Wikipedia is to be believed, a earthquake with Richter magnitude 3.0 releases approximately the same amount of kinetic energy as this. However, a 3.0 earthquake isn't that strong, and I'm not sure whether this would be detectable by a land-based station hundreds of thousands of miles away. (Obviously, there are no seismometers in the North Atlantic Ocean.)
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Old 03-07-2016, 08:03 AM
MrDibble MrDibble is offline
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However, a 3.0 earthquake isn't that strong, and I'm not sure whether this would be detectable by a land-based station hundreds of thousands of miles away.
It's highly variable how far it would be detectable.

But hundreds of thousands of miles? You are aware that anything more than 24 000 miles is as far as you can get away from the epicentre and not be on your way back, right?
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(Obviously, there are no seismometers in the North Atlantic Ocean.)
Sooooon...
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Old 03-07-2016, 09:02 AM
sich_hinaufwinden sich_hinaufwinden is offline
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...You are aware that anything more than 24 000 miles is as far as you can get away from the epicentre and not be on your way back, right?
Wouldn't half the circumference (12,000 mi) be as far away as you could get?
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Old 03-07-2016, 09:13 AM
MikeS MikeS is offline
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But hundreds of thousands of miles? You are aware that anything more than 24 000 miles is as far as you can get away from the epicentre and not be on your way back, right?
That's what I get for posting too early in the morning. I meant "hundreds or thousands of miles away."
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Old 03-07-2016, 09:49 AM
LSLGuy LSLGuy is online now
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Don't feel bad. I make that of/or typo 3x/day. It's surprisingly hard to spot.

Back to the OP ...

If that was to happen today it might not be detected on seismometers. But is sure would be detected by SOSUS (wiki) and its successor systems.

Last edited by LSLGuy; 03-07-2016 at 09:51 AM. Reason: typos are surprisingly hrad to sopt.
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Old 03-07-2016, 12:14 PM
MrDibble MrDibble is offline
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Wouldn't half the circumference (12,000 mi) be as far away as you could get?
Doh, yes. That'll teach me to worry about getting the miles right and forgetting to actually halve it.
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Old 03-07-2016, 12:59 PM
LSLGuy LSLGuy is online now
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Originally Posted by sich_hinaufwinden View Post
Wouldn't half the circumference (12,000 mi) be as far away as you could get?
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Originally Posted by MrDibble View Post
Doh, yes. That'll teach me to worry about getting the miles right and forgetting to actually halve it.
Actually it's worse than that.

Seismic waves don't travel along the surface, but rather through the interior which can represent a short-cut. They don't follow a straight line path though. So even though the Earth's diameter is about 8000 miles and that forms the geometric worst-case minimum, that's not a practical minimum.

See https://en.wikipedia.org/wiki/Seismic_wave for more.

Last edited by LSLGuy; 03-07-2016 at 01:01 PM.
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Old 03-07-2016, 03:38 PM
MrDibble MrDibble is offline
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Actually it's worse than that.

Seismic waves don't travel along the surface, but rather through the interior which can represent a short-cut.
Some do, some don't. From your own cite.

Last edited by MrDibble; 03-07-2016 at 03:38 PM.
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Old 03-08-2016, 01:49 AM
Hail Ants Hail Ants is offline
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Just FYI, the Richter scale is logarithmic which, if you don't know anything about math, means it is very non-intuitive. In human terms anything below a 5.0 is essentially nothing, anything above a 5.0 is a small to large catastrophe...
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Old 03-08-2016, 01:56 AM
MrDibble MrDibble is offline
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Just FYI, the Richter scale is logarithmic which, if you don't know anything about math, means it is very non-intuitive. In human terms anything below a 5.0 is essentially nothing, anything above a 5.0 is a small to large catastrophe...
Below 5 is not "essentially nothing". I'd say 3-5 is the range for "noticeable, but almost certainly not damaging" - and if you're not used to 'quakes, noticeable is not nothing.
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