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-   -   Could the Earthquake have caused this? (http://www.physicsforums.com/showthread.php?t=59601)

errorist Jan12-05 07:46 PM

Could the Earthquake have caused this?
 
Earthquake tsunami in India.
Could a Earthquake of this size have caused a mountain to be thrust up in a different region of the world and cause this accident?

http://www.spacedaily.com/news/submarine-05a.html

russ_watters Jan13-05 07:54 AM

No, this sort of thing happens relatively often and its simply a result of not having accurate enough maps of the ocean floor. Remember, if a surface ship can run aground (and they do, a lot) a sub can too.

Astronuc Jan13-05 08:07 AM

Parts of the Indian Ocean have changed, and will need to be recharted, particluarly of the coast of Sumutra.

The area where the submarine was operating (some 560 kilometers (350 miles) south of Guam - at a depth of 120 meters (400 feet) ) should not have been affected by the Sumutran earthquake.

On the other hand, the Sumutran earthquake is a consequence of the dynamics of the earth's crust. It is an extension of the Pacific Ring of Fire where volcanic activity and earthquakes are quite common.

It would appear, as Russ stated, that some areas are not adequately mapped as they perhaps should be.

pizza1512 Jan13-05 08:09 AM

What about the latitudes and the longitudes of places?...

russ_watters Jan13-05 11:52 AM

A quick google turned up THIS article that says the sea-floor may have shifted up and down by up to 60 feet, but doesn't say if it would be permanent. It also says it may have a small, but noticeable effect on land far away. From what I understand, a powerful earthquake on the San Andreas fault involves a shift of just a few feet - rememeber though, a continent moving 5 feet requires the release of a truly massive amount of energy.

Regarding ocean-floor mapping - it has only recently become possible to have really accurate maps of the ocean floor. Typically, within a few miles of shore, you'll have a depth reading every 100 m or so. Out in the open ocean, they can be 10 km apart. It would seem to me that this sub, if operating that close to the bottom, should have had better charts, but thats a lot of land-area to chart and it shouldn't be too surprising that that's the best we have.

One of my profs at the Naval Academy was an officer onboard a sub that ran-aground for this exact same reason (uncharted seamount), which pretty much ended his career. The picture painted by the article is of a cliff - that's not generally how they work. Usually, its just a few degrees of rise over many miles. One thing thats not clear to me yet - the sub may not have had its depth-sounder turned on, which is apparently common for military subs because it makes noise.

edit: a little more - googling shows some people speculating that this was a collision, not a grounding. Apparently, the water was supposed to be much too deep for even an uncharted seamount. My prof said that his sub had dents in it that no one was allowed to talk about, but everyone was proud of...

Astronuc Jan13-05 01:57 PM

See this picture for the location of the Pacific Ring of Fire.

http://pubs.usgs.gov/publications/text/fire.html

It shows the major plate boundaries.

Guam is at the southern end of the chain of Northern Mariana Islands that border the Marianas Trench ( http://www.ngdc.noaa.gov/mgg/image/marianas.html ). This area also lies north of the Bougainville trench. It is possible that the region between the Mariana and Bouganiville trenches is being pushed up. Maybe someday, a new chain of islands will popup there.

As far as I know, US subs generally run silent so as not to be detected. Therefore it would seem likely that active sonar was not in operation.

errorist Jan13-05 02:17 PM

Perhaps, This uderwater mountain took a few days to rise. If it took a few days to rise it may not show up as a Earthquake?

russ_watters Jan13-05 02:29 PM

Quote:

Quote by errorist
Perhaps, This uderwater mountain took a few days to rise. If it took a few days to rise it may not show up as a Earthquake?

No, there is just far too much energy required to make a new mountain in a few days for it not to be noticeable. Even small earthquakes are measurable from thousands of miles away.

matthyaouw Jan15-05 03:01 PM

Differences in temperature and salinity in water columns affect the refracting of sound waves, causing innacurate depth readings on sonar. Perhaps an over-estimation of the depth of the water was one of the factors that caused the accident.


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