New Tsunami warning

[drezee]

7.2 earth quake SE of India

[micktooth]

TSUNAMI BULLETIN NUMBER 001
PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS
ISSUED AT 1556Z 24 JUL 2005

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT
ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

... TSUNAMI INFORMATION BULLETIN ...

THIS MESSAGE IS FOR INFORMATION ONLY.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 1542Z 24 JUL 2005
COORDINATES - 7.9 NORTH 92.1 EAST
LOCATION - NICOBAR ISLANDS INDIA
MAGNITUDE - 7.2

EVALUATION

THIS EARTHQUAKE IS LOCATED OUTSIDE THE PACIFIC. NO TSUNAMI THREAT
EXISTS TO COASTLINES IN THE PACIFIC.

HOWEVER - EARTHQUAKES OF THIS SIZE SOMETIMES GENERATE LOCAL
TSUNAMIS THAT CAN BE DESTRUCTIVE ALONG COASTS LOCATED WITHIN
A FEW HUNDRED KILOMETERS OF THE EARTHQUAKE EPICENTER. AUTHORITIES
IN THE REGION OF THE EPICENTER SHOULD BE AWARE OF THIS
POSSIBILITY AND TAKE APPROPRIATE ACTION.

THIS CENTER DOES NOT HAVE SEA LEVEL GAUGES OUTSIDE THE PACIFIC
SO WILL NOT BE ABLE TO DETECT OR MEASURE A TSUNAMI IF ONE WAS
GENERATED. AUTHORITIES CAN ASSUME THE DANGER HAS PASSED IF NO
TSUNAMI WAVES ARE OBSERVED NEAR THE EPICENTER WITHIN AN HOUR OF
THE EARTHQUAKE.

THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS
ADDITIONAL INFORMATION BECOMES AVAILABLE.

THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE BULLETINS
FOR ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

[cycloneye]

http://earthquake.usgs.gov/eqinthenews/2005/usaxay/

[Janice]

This just burns me up. I heard this and TWC and CNN are not saying anything. I guess People In The News is more important.
I hope people don't get killed, but at least they are preparing for the worse.

Thanks for all the info, guys. I can depend on Storm2k.

[tndefender]

This just burns me up. I heard this and TWC and CNN are not saying anything. I guess People In The News is more important.
I hope people don't get killed, but at least they are preparing for the worse.

Thanks for all the info, guys. I can depend on Storm2k.

Reported on MSNBC.com: http://www.msnbc.msn.com/id/8689778/

[InimanaChoogamaga]

And on the BBC:
http://news.bbc.co.uk/1/hi/world/south_asia/4713011.stm

and Fox:
http://www.foxnews.com/story/0,2933,163481,00.html

Two <I>very</I> different news outlets.
Fox just has the AP story which is everywhere.

[mike18xx]

7.2 is usually below the threshold magnitude necessary to generate a destructive tsunami.

[Brent]

Thailand has cancelled the Tsunami warning.

[Mac]

7.2 is usually below the threshold magnitude necessary to generate a destructive tsunami.

My understanding is that the magnitude of the quake has far less to do with whether a tsunamic is produced than whether the quake was a strike-slip quake (horizontal displacement) or a subsidence quake (vertical displacement). For obvious reasons, subsidence quakes are considerably more likely to produce tsunamis. And even moderate subsidence quakes are capable of producing killer tsunamis, given the proper underwater dynamics are at play.

[mike18xx]

7.2 is usually below the threshold magnitude necessary to generate a destructive tsunami.

My understanding is that the magnitude of the quake has far less to do with whether a tsunamic is produced than whether the quake was a strike-slip quake (horizontal displacement) or a subsidence quake (vertical displacement). For obvious reasons, subsidence quakes are considerably more likely to produce tsunamis. And even moderate subsidence quakes are capable of producing killer tsunamis, given the proper underwater dynamics are at play.

Quake magnitude is (now) a factor of ground displacement -- which directly correlates to how much water it could also displace. 7.2 is normally too small. My logrithmic math skills are fuzzy, but I believe that the 9.0 Dec 26 quake featured approximately 80 to 90 times the displacement of a 7.2.

[Mac]

7.2 is usually below the threshold magnitude necessary to generate a destructive tsunami.

My understanding is that the magnitude of the quake has far less to do with whether a tsunamic is produced than whether the quake was a strike-slip quake (horizontal displacement) or a subsidence quake (vertical displacement). For obvious reasons, subsidence quakes are considerably more likely to produce tsunamis. And even moderate subsidence quakes are capable of producing killer tsunamis, given the proper underwater dynamics are at play.

Quake magnitude is (now) a factor of ground displacement -- which directly correlates to how much water it could also displace. 7.2 is normally too small. My logrithmic math skills are fuzzy, but I believe that the 9.0 Dec 26 quake featured approximately 80 to 90 times the displacement of a 7.2.

Well, kind of. A 9.0 does release approximately 80 times more energy than a 7.2. But energy released at the fault line does not necessarily correlate to the risk for tsunami. Yes, it generally does. But there are other dynamics at play, such as the depth of the quake, the length of the rupture, and the underwater geography/topography. A tsunami is generally created by vertical underwater displacement. You could have a 6.2 earthquake in one area and a 7.2 earthquake in another that caused similar tsunamis due to differences in various factors. The speed at which the vertical subsidence occurs is also a factor. Think of playing with a toy submarine in the bath tub when you were a kid. If you raise the sub towards the surface rapidly, you get a far bigger wave than if you raise it to the surface slowly. The December 2004 earthquake lasted for nearly 10 minutes. Can you imagine the wave that could have been created if that fault line had just suddenly failed rather than "ripping?"

[wxmann_91]

A 7.2 quake prompted a Tsunami Warning for much of the west coast a month ago, or do ye not remember?

Tsunamis can be created by a 7.2 quake. A moderate quake can generate an underwater landslide, and it's usually the landslide that causes the tsunami. From Wikipedia:

An earthquake which is too small to create a tsunami by itself may trigger an undersea landslide quite capable of generating a tsunami.

Examples:

April 1, 1946 Hilo, HI tsunami was caused by only a 7.8 quake.

On December 28, 1908, a 30 ft high tsunami struck Messina, Italy, killing 100,000 people. The town had a population of only 150,000 before. (2 out of 3 people in the town were killed) The tsunami was caused by a 7.2 quake.

1929 - 7.2 quake causes a 7 meter high tsunami, killing 29 people.

1979 - Pacific coast of Colombia and Ecuador rocked by a tsunami, 259 dead. Caused by a 7.9 quake.

July 17, 1998 - Papua New Guinea, 12 meter high tsunami caused by 7.1 quake and undersea landslide kills 2200 people.