Re: New tsunami advisory warning - Japan
On Mon, Mar 28, 2011 at 1:59 AM, <Valdis.Kletnieks@vt.edu> wrote:
*yawn*. A foot and a half isn't going to be all *that* bad
Remember a wall of tsunami water travels in general at approx 970 kph (600 mph), think about it.
On Sun, Mar 27, 2011 at 6:28 PM, andrew.wallace < andrew.wallace@rocketmail.com> wrote:
On Mon, Mar 28, 2011 at 1:59 AM, <Valdis.Kletnieks@vt.edu> wrote:
*yawn*. A foot and a half isn't going to be all *that* bad
Remember a wall of tsunami water travels in general at approx 970 kph (600 mph), think about it.
That's in deep water, where the height of the wave might be a few inches at most. Once it reaches shallow water the speed drops significantly and the height increases. Scott
And then you can have lens effects, where the waves reflections on the coast, focus unto a point on the coastline. On 3/28/11 14:34 , "Scott Howard" <scott@doc.net.au> wrote:
On Sun, Mar 27, 2011 at 6:28 PM, andrew.wallace < andrew.wallace@rocketmail.com> wrote:
On Mon, Mar 28, 2011 at 1:59 AM, <Valdis.Kletnieks@vt.edu> wrote:
*yawn*. A foot and a half isn't going to be all *that* bad
Remember a wall of tsunami water travels in general at approx 970 kph (600 mph), think about it.
That's in deep water, where the height of the wave might be a few inches at most.
Once it reaches shallow water the speed drops significantly and the height increases.
Scott
*yawn*. A foot and a half isn't going to be all *that* bad
Sorry to continue off topic: Try to imagine ... a temporary very high tide, rather than a cresting wave. In addition to the "height", it's the wave-length you have to take into account. Tsunami's rarely become towering breaking waves. [That said, tsunamis can form into a bore - a step-like wave with a steep breaking front. Likely if the tsunami moves from deep water into a shallow river / bay] 1 1/2 foot on top of an existing high tide, could easily cause further flooding in the wrong locations (although as mentioned, not to the levels already experienced).
travels in general at approx 970 kph (600 mph)
True in the deepest parts of open ocean - upon reaching the shore-line it'll be travelling a lot slower. </off-topic> // Gav
Gavin Pearce wrote:
*yawn*. A foot and a half isn't going to be all *that* bad
Sorry to continue off topic:
Try to imagine ... a temporary very high tide, rather than a cresting wave. In addition to the "height", it's the wave-length you have to take into account. Tsunami's rarely become towering breaking waves.
Quite right. The other part is that the water becomes a very fast moving river, especially in places where it's not normally one. Watching the footage from the Santa Cruz harbor it wasn't the height that was a particular problem, but the fact that all of a sudden you had a 5-10 knot current. And this happened at low tide, so it would have been far worse if it happened at high tide. There was a pretty spectacular photo of the tsunami that appeared to be around the Emeryville flats. Only about 6 or so inches high, but massive. Had it been at high tide, it could have probably done some nasty things... like, oh for example, the sewage treatment plant next to the Bay Bridge comes to mind. Mike
Michael Thomas wrote:
Gavin Pearce wrote:
*yawn*. A foot and a half isn't going to be all *that* bad
Sorry to continue off topic:
Try to imagine ... a temporary very high tide, rather than a cresting wave. In addition to the "height", it's the wave-length you have to take into account. Tsunami's rarely become towering breaking waves.
Quite right. The other part is that the water becomes a very fast moving river, especially in places where it's not normally one. Watching the
I don't underestimate the power of even a small tsunami. I have friends rendered homeless by the Santa Cruz tsunami (their boat being their only home). Though I can understand one is underwhelmed by a mag 6.x earthquake in that region considering I believe more than 20 6+ ones happened there since the first mag 7.2 earthquake that happened 2-3 days before the mag 9 one. Most recent ones: http://earthquake.usgs.gov/earthquakes/recenteqsww/Maps/10/145_40_eqs.php -- http://goldmark.org/jeff/stupid-disclaimers/ http://linuxmafia.com/~rick/faq/plural-of-virus.html
participants (6)
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andrew.wallace -
Franck Martin -
Gavin Pearce -
Jeroen van Aart -
Michael Thomas -
Scott Howard