[QUOTE=cheesehead;243615]"completely"?
[/QUOTE]
Sufficiently to merit all possible warning to be issued
immediately.
[QUOTE]
So, people in some directions are more in danger than people in others?
[/QUOTE]
Yes, and in a predictable way, as if triage was appropriate in
such an emergency.

I would guess that the severity of the tsunami depended
on how much vertical movement of the sea floor was involved.
But I would guess that even this could be gauged from prior
knowledge of the faultline involved and/or seismological data.

As Axn said, "early warning" involves two distinct aspects:

1) Recognizing the immanent risk.
2) Warning the folk likely to be affected.

My "gripe" is that it sounds to me as if "failing to have
the buoys (or whatever) in place" was advanced as an excuse
for failure to do either 1) or 2).

David

[QUOTE=davieddy;243677]No detecting buoys in the Indian Ocean....[/QUOTE]
Because the USA hates brown people.[attach]6012[/attach]

[QUOTE=davieddy;243724]Sufficiently to merit all possible warning to be issued immediately.[/QUOTE]What about [I]alarm fatigue[/I] (AKA "Boy who cried wolf" syndrome)?

This makes it important to take steps not to send alarms unnecessarily to areas where it's not necessary. (Sure, the immediate area has to be warned in all directions, but farther areas could get first a preliminary alert, then a warning (or all-clear) where justified by better data.) Once directionality is established (which buoys would aid), then the alarm can be concentrated where needed.

[quote]as if triage was appropriate in such an emergency.[/quote]Not crying "wolf" is appropriate.

[quote]I would guess that the severity of the tsunami depended on how much vertical movement of the sea floor was involved. But I would guess that even this could be gauged from prior knowledge of the faultline involved and/or seismological data.[/quote]Just how do you propose establishing, without measurements such as buoys provide, the relationship between (a) prior knowledge and seismological data, and (b) direction, speed and severity of this particular tsunami?

Is the earliest seismological data from a quake (or other event) always enough to determine the details of ocean floor movement sufficiently to predict tsunamis?

[quote]1) Recognizing the immanent risk.
2) Warning the folk likely to be affected.

My "gripe" is that it sounds to me as if "failing to have the buoys (or whatever) in place" was advanced as an excuse for failure to do either 1) or 2).[/quote]I don't understand your reasoning. Isn't having "the buoys (or whatever) in place" part of 1) ? So that failure to do so was indeed an explanation, not an exculpatory excuse, for insufficiency of 1) ?

This is a (possibly interesting) BTW:

What do these buoys do that boats can't?

David

[QUOTE=Uncwilly;243740]Because the USA hates brown people.[attach]6012[/attach][/QUOTE]

Yes, I know you're just try to dig me deeper into
the brown stuff, but I'd temporarily forgotten GWB's
"War On Terror".

[url=http://www.youtube.com/watch?v=xSuSWZUYHmg]God on our side[/url]

David

[QUOTE=davieddy;243845]This is a (possibly interesting) BTW:

What do these buoys do that boats can't?[/QUOTE]

As far as I understand...

1. They are at fixed (or at least, un-powered), known locations.

2. They are appropriately distributed -- boats / ships tend to move around and might not be at the best locations to detect what needs to be detected.

3. They are particularly sensitive to the (average) depth of the ocean.

3.1. Please note that until the depth of the ocean through which the massive amount of wave energy (tsunami) is passing becomes shallow, the actual delta of the average depth can be less than a meter.

3.1.1. I.E. less than the higher-frequency waves which might be being experienced. Read:unmeasurable by standard navigation kit (and, of course, humans) on most boats / ships which are more concerned about Lat/Long/Direction/True Speed than (Deep) Depth.

[QUOTE=davieddy;243849]Yes, I know you're just try to dig me deeper into
the brown stuff, but I'd temporarily forgotten GWB's
"War On Terror".

[URL="http://www.youtube.com/watch?v=xSuSWZUYHmg"]God on our side[/URL]

David[/QUOTE]

Before I cop it again from Brian or Richard, I am sure there
are several (probably untold) stories about folk in the know
doing their best.

David

[QUOTE=chalsall;243850]As far as I understand...

1. They are at fixed (or at least, un-powered), known locations.

2. They are appropriately distributed -- boats / ships tend to move around and might not be at the best locations to detect what needs to be detected.

3. They are particularly sensitive to the (average) depth of the ocean.[/QUOTE] 4. They are much cheaper to operate 25/7/366 (left as an exercise to the reader).
5. Because of the way they operate (tied down and design) , they can detect the fast pulse of the the wave despite the standard slower but larger amplitude waves.

Thinking about this problem space over dinner...
 

Thinking about this a bit further this evening, a thought came to me. I'm sure this has been thought about by others already who are far smarter than me, but please let me share...

A methodology far better than buoys might be a detection matrix resting on the sea floor.

These could be autonomous, self contained, self powered (batteries and/or fuel cell) modules which could be dropped to the sea floor from ships. These would measure the weight of the water above them on a very regular basis. When the power supply is about to run out, you drop some more.

Radio waves (RF) don't travel through water well. But audio waves do (just ask the whales).

Unlike a buoy which will move around somewhat on its tether, a sensor sitting on the ocean floor will only move a few cm a year nominally, and will always be able to measure the pressure difference of the water sitting above it to an extremely accurate degree.

I haven't researched the prior art to see if this has been done already. But it seems a pretty reasonable solution to me -- and thus I must conclude that it has already been implemented.

[QUOTE=chalsall;243897]A methodology far better than buoys might be a detection matrix resting on the sea floor.

These could be autonomous, self contained, self powered (batteries and/or fuel cell) modules which could be dropped to the sea floor from ships. These would measure the weight of the water above them on a very regular basis. When the power supply is about to run out, you drop some more.

Radio waves (RF) don't travel through water well. But audio waves do (just ask the whales).[/QUOTE]Problems/differences.

Buoys are solar powered [B]+1[/B] buoys

Seafloor sensors would require a buoy to transmit data to the stations via radio waves at the speed required for some warnings. [B]+1[/B] buoys

[QUOTE=Uncwilly;243910]Problems/differences.[/QUOTE]

I respect and appreciate debate.

WRT buoys being solar powered. Yes. But you can pack a *whole* lot of energy into (for example) a 45 gallon drum containing tanks of highly compressed (but not necessarily liquid) oxygen and methane (for example).

Add a fuel-cell, and you're good to go for (probably) years.

Please don't forget that many wild animal researchers "tag" their subjects with GPS receiving collars which are battery-only powered which last for over a year. (GPS reception and resolution is relatively expensive from a power perspective.)

@Uncwilly: "Seafloor sensors would require a buoy to transmit data to the stations via radio waves at the speed required for some warnings.

Not always.

"Sound" travels at approximately 1.5 km/s through water. And much further than through "air".

Yes, I agree that at some point there must be at least one receiver listening to the sea-bed monitoring stations.

But they don't always have to be buoys.