How Does a Tsunami Cause a Dramatic Fall in Sea Level?

[Nailsy]

Can anyone explain to me how an approaching tsunami would cause a dramatic fall in sea level before it comes ashore.

 

[russ_watters]

Ever been to the beach and notice how the ocean recedes toward a coming wave? Its exactly the same with a tsunami except bigger. The water in the tsunami has to come from somewhere, so it comes from in front of and behind the tsunami.

A wave is a wave: it goes up and down.

 

[Nailsy]

It seems that in the normal ocean wave scenario the ocean does not recede towards a coming wave, but rather the water that was washed ashore is being pulled by gravity back to the ocean. I believe the recession of the sea (up to 800m in some instances) would have to be of a different nature. I am still pondering this question.

 

[ray b]

has anyone found a good hard data site on this or other Tsunami's

I would like to know if the azores volcano/island that is predicted to landslide
GOES would Miami be protected by the Bahamas or would the wave reinforce
and be greater after passing around the islands

and how far inland and/or up hill will a Tsunami cause distruction
would the barrier islands and a wide shalow bay protect us in Miami a few miles inland??

 

[dem45133]

Seems basic science education was severely lacking...

Not to degrade the tragedy of it, but if thousands of people noticed the massive recession (6th grade science says a tidal wave is approaching...), why didn't they all head inland? I supposed the few that did notice and say something would have been ignored.

The biggest tragedy is that some of the gov'ts were notified, but chose to ignore it, citing tourism (stated on 700 am radio). If its true, that's the real tragedy! There may not have been time for the closest shores, but likely was on the more distant.

 

[Gokul43201]

Not to degrade the tragedy of it, but if thousands of people noticed the massive recession (6th grade science says a tidal wave is approaching...), why didn't they all head inland? I supposed the few that did notice and say something would have been ignored.

Want to guess how many of the people in the affected areas had the opporunity to attend any kind of school at all ?

 

[hitssquad]

if thousands of people noticed the massive recession (6th grade science says a tidal wave is approaching...), why didn't they all head inland?

http://www.spacedaily.com/news/tectonics-04zf.html


--
A 10-year-old British schoolgirl saved the lives of hundreds of people in southern Asia by warning them a wall of water was about to strike, after learning about tsunamis in geography class, British media reported on Saturday.

Tilly, who has been renamed the "angel of the beach" by the top-selling tabloid The Sun, was holidaying with her family on the Thai island of Phuket when she suddenly grasped what was taking place and alerted her mother.

"Last term Mr Kearney taught us about earthquakes and how they can cause tsunamis," Tilly was quoted as saying by The Sun.

"I was on the beach and the water started to go funny. There were bubbles and the tide went out all of a sudden.

"I recognised what was happening and had a feeling there was going to be a tsunami. I told mummy."
--

 

[dem45133]

Well, its all history now... and we won't go into where the lions share of the aid money is or will finally end up.

But an interesting note my sister saw was a commentary noting that no animals (other than pets) were found in the debris, and that several indiginous people had commented about their domesticated (farm) animals had become nervous and agitated, eventally breaking through their fences(where there were fences) and headed inland, and that many wild animals were observed doing the same in the immediate 72 hours preceeding the quake. Too bad we as humans lost (or ignore) those instincts.