Thanks for those links.

Yes, but divers underwater usually are not.

Here's another account from a diver in the water during the tsunami.

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Paradise then terror for vacationing scuba diver
By TERI SFORZA
The Orange County Register

USA - She was always afraid of the ocean.

When a friend invited Lea Kreidie on a Christmas break trip to Kuala
Lumpur, Malaysia, then Thailand, to learn scuba diving, Kreidie
hesitated. I don't like the water, Kreidie told her mother. I don't
like being submerged. It hurts my ears.

Little did she know.

Kreidie's mother, Lina Kreidie, teaches political science at UC
Irvine. She took a logical approach to her daughter's phobia. "I told
her to do it and overcome this fear," Lina Kreidie said Tuesday from
her Laguna Niguel home. "I said, 'Go. You will visit different
countries. It will be wonderful.'"

On Dec. 21, Kreidie, a 21-year-old studying communications and
political science at UC Berkeley, headed to Malaysia with her friend's
family. They spent time in Kuala Lumpur - a gleaming fusion of the
ancient and the modern - and then headed to the idyllic Thai island of
Phi Phi , a tropical paradise of soaring limestone cliffs, powdery
white beaches and brilliant crystalline waters. Swallowing her fear,
Kreidie checked into a hotel and began working on her scuba-diving
certification.

The world beneath the waves was a revelation. It was a glittering
jewel box of coral reefs and fish that gleamed like shards of stained
glass - parrot fish, clown fish, ghost pipe fish, angel fish, sea
snakes, silky sea anemones.

"This island is like paradise," she wrote in an e-mail to her family
on Saturday. "I do not know what heaven is like, but if it is anything
like this, I will be content."

The next day was going to be a very big day, her e-mail said: her
final open-water dive. After that, she would be a certified scuba
diver. She was feeling so much more comfortable in the water. She'd
come such a long way.

The next morning was Sunday. The morning a monstrous earthquake rocked
the coast of Sumatra. The morning murderous waves began pulsing
through the Indian Ocean and South China Sea.

It was early Sunday in Laguna Niguel when Kreidie's family first heard
the news of the devastation in Southeast Asia. An icy panic coursed
through her mother. "I saw her island on TV," Lina Kreidie said. The
seaside hotels were obliterated. "If she's scuba diving, she's gone,"
she said. "If she was in the hot tub, she's gone."

Panic turned to hysteria. "I went crazy," Lina Kreidie said.

Kreidie's sister Lana immediately called the American Embassy in
Thailand. They had no information about Phi Phi; all communication
lines were down. She kept calling and calling, and was eventually able
to get a list of people taken to the hospital; Kreidie wasn't on it.

Soon, friends and relatives crammed the house, phones welded to their
ears. They called the Red Cross: nothing. They called every hotel on
Phi Phi island they could reach; none listed Kreidie as a guest. They
prayed she had made it to high ground. They prayed she wasn't in the
water.

When the tsunami swept through Sunday morning, Kreidie was in the open
ocean, deep under water. The fish were acting strange. Rather than
swimming away, the fish were bunching up below the divers, almost as
if they were trying to find shelter.

She felt pressure. They all started drifting. Then a mighty thrust
launched her forward, sucked her down some 45 feet, and shot her up
again. She lostcontrol over herbody, her movements, her orientation in
space. The water, once so clear, became sandy and dense. But she
didn't panic; she had so little experience diving that she didn't know
how strange it was.

When they finally surfaced, the instructor said that was no ordinary
current.

A Thai ship plucked them from the sea, and they soon learned they
would not be going back to Phi Phi. There was nothing left of their
hotel. No one knew if another rogue wave was on the way. Soon, they
could see debris floating in the ocean - trees, food, bottles of
water.

"I was scared out of my mind," Kreidie said.

Kreidie was transported to Phuket, then to Bangkok. Kind locals made
sure she had food and a place to sleep. But she had no passport. No
clothes. No money. She called home with a borrowed cell phone.

About 4 p.m. Sunday, the phone rang in Laguna Niguel. Mom Lina Kreidie
answered. She screamed, then fainted.

Sister Lana grabbed the phone. Kreidie was in tears. "Lana, are you
guys OK?" Kreidie said, worried about the agony she put her family
through. "You should see around here," she said. "It's horrible. I've
never seen anything like this."

Sister Lana sprang to action, getting back on the phone with the
embassy, faxing over proof of Kreidie's citizenship, explaining to her
sister what she must do next. Today, Kreidie flies back to Kuala
Lumpur. Her mother will meet her there, hug her so tight she won't be
able to breathe and then accompany her back to America.

"It's just unbelievable. It's a miracle," Lina Kreidie said. "I'm sure
thousands are suffering now, and I feel for them. I told her, 'God has
plan for you, and you have to help these people. You survived.' "

Kreidie's first instinct was to say she'd never dive again. "But after
thinking about it, I feel like I could handle anything at this point,"
she said from Bangkok. "I just dove in a tsunami.

"I feel like I should definitely devote part of my life to helping
people. I feel lucky to be alive; I can't even tell you. Somebody is
watching me. I thank God every single moment."

Sister Lana has learned a powerful lesson. "Your worst enemy will save
your life," she said. "Face your fears and try to overcome, whether it
be the ocean or anything. That's the moral of the story."

Probably not, mainly because the amplitude of the wave is small and it
would be very difficult to differentiate the tsunami from normal
surface chop without some advanced signal processing that would have to
be done onboard the satellite. Most of our satellite imaging systems
were designed to see relatively slow moving phenomena, so I doubt
there's any hardware or software in place in the satellites themselves
to do an FFT or Doppler analysis of an image.

The present tsunami warning system uses underwater pressure transducers
to detect the pressure wave from a seismic event or eruption (or even a
meteor strike, were one to occur) measure and evaluate the potential
effect of a tsunami.  Here are a couple of interesting links:

http://www.magazine.noaa.gov/stories/mag153.html

http://www.pmel.noaa.gov/tsunami/Dart/Flash/CODEframe4DART.html

Since this system has been working well in the Pacific ocean for quite
a while, I expect it would be easiest to just duplicate it in the
Indian Ocean. Of course, detecting the wave is only half the challenge,
the second half is getting the information out to the people in danger
and getting them to take the appropriate action.

Alan