Posted on 03/24/2007 5:58:55 PM PDT by bd476
Just heard on the radio and just now confirmed on USGS. More to come...
Tsunami time?
Surfs Up!!!
It is Godzilla!!!!!!!!!!
What about this one... http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/at00141360.php
Ring-O-Fire is active tonight.
Earthquake Details
Magnitude 6.2 Date-Time
- Sunday, March 25, 2007 at 00:42:02 (UTC)
= Coordinated Universal Time- Sunday, March 25, 2007 at 9:42:02 AM
= local time at epicenterLocation 37.537°N, 136.438°E Depth 32.7 km (20.3 miles) Region NEAR THE WEST COAST OF HONSHU, JAPAN Distances 105 km (65 miles) N of Kanazawa, Honshu, Japan
165 km (100 miles) N of Fukui, Honshu, Japan
185 km (115 miles) WNW of Nagano, Honshu, Japan
360 km (225 miles) NW of TOKYO, Japan
Location Uncertainty horizontal +/- 9.3 km (5.8 miles); depth +/- 26.4 km (16.4 miles) Parameters Nst=102, Nph=102, Dmin=760.4 km, Rmss=1.1 sec, Gp= 43°,
M-type=body magnitude (Mb), Version=6Source USGS NEIC (WDCS-D)
Event ID us2007aiae
- This event has been reviewed by a seismologist.
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Earthquake Details Magnitude 7.3
Date-Time Sunday, March 25, 2007 at 00:42:02 (UTC) = Coordinated Universal Time Sunday, March 25, 2007 at 9:42:02 AM = local time at epicenter
Location 37.537°N, 136.438°E
Depth 32.7 km (20.3 miles)
Region NEAR THE WEST COAST OF HONSHU, JAPAN
Distances 105 km (65 miles) N of Kanazawa, Honshu, Japan
165 km (100 miles) N of Fukui, Honshu, Japan
185 km (115 miles) WNW of Nagano, Honshu, Japan
360 km (225 miles) NW of TOKYO, Japan
Location Uncertainty horizontal +/- 9.3 km (5.8 miles);
depth +/- 26.4 km (16.4 miles) Parameters Nst=102, Nph=102, Dmin=760.4 km, Rmss=1.1 sec, Gp= 43°,
M-type=moment magnitude (Mw), Version=8
Source USGS NEIC (WDCS-D)
Event ID us2007aiae
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TSUNAMI INFORMATION STATEMENT NUMBER 001
PACIFIC TSUNAMI WARNING CENTER
0306 PM HST 24 MAR 2007
TO - CIVIL DEFENSE IN THE STATE OF HAWAII
SUBJECT - TSUNAMI INFORMATION
THIS STATEMENT IS FOR INFORMATION ONLY. NO ACTION REQUIRED.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
ORIGIN TIME - 0241 PM HST 24 MAR 2007
COORDINATES - 37.3 NORTH 136.5 EAST
LOCATION - NEAR WEST COAST OF HONSHU JAPAN
MAGNITUDE - 7.1 MOMENT
EVALUATION
BASED ON ALL AVAILABLE DATA A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS
NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII. REPEAT. A
DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO
TSUNAMI THREAT TO HAWAII.
THIS WILL BE THE ONLY STATEMENT ISSUED FOR THIS EVENT UNLESS
ADDITIONAL DATA ARE RECEIVED.
Another thread going about a 7.1 at Vanuatu.
That is one hell of a jump in energy released. From 6.3 to 7.3?
According to IRIS they were 2 minutes apart
http://www.iris.edu/seismon/last30.html
The ole Ring Of Fire is flexing her muscle...
USGS revised it back down to M 6.7 after revising it up to 7.3, actually.
The phenomenon we call a tsunami is a series of waves of extremely long wavelength and period generated in a body of water by an impulsive disturbance that displaces the water. Although tsunamis are often referred to as "tidal waves" by English-speaking people, they are not caused by the tides and are unrelated to them.
Tsunamis are primarily associated with earthquakes in oceanic and coastal regions. When an earthquake occurs, the energy travels outward in all directions from the source. This can be illustrated by throwing a pebble into a small, still pond. The pebble represents a meteorite or some other energy source, and the pond represents the ocean. The ripples that travel out in all directions from the focus, or the point where the pebble hit the water, represent the energy that creates a sea wave. Notice how the waves become larger as they reach shore, where the water is shallower.
Detecting tsunamis is a very difficult thing to do. When a wave begins in the deep ocean waters, it may only have a height of about twelve to twenty-three inches and look like nothing more than the gentle rise and fall of the sea surface. An example of how easy tsunamis are to overlook is the Sanriku tsunami, which struck Honshu, Japan, on June 15, 1896.
Fishermen twenty miles out to sea didn't notice the wave pass under their boats because it only had a height at the time of about fifteen inches. They were totally unprepared for the devastation that awaited them when they returned to the port of Sanriku. Twenty-eight thousand people were killed and 170 miles of coastline were destroyed by the wave that had passed under them.
Tsunamis in deep water can have a wavelength greater than 300 miles (500 kilometers) and a period of about an hour. This is very different from the normal California tube, which generally has a wavelength of about 300 feet (100 meters) and a period of about ten seconds. (The period of a wave is the time between two successive waves.)
Tsunamis are shallow-water waves, which means that the ratio between water depth and wavelength is very small. These shallow-water waves move at a speed equal to the square root of the product of the acceleration of gravity (9.8m/s/s) and the water depth. The deeper the water, the faster and shorter the wave is. For example, when the ocean is 20,000 feet deep, a tsunami travels at 550 miles per hour. At this speed, the wave can compete with a jet airplane, traveling across the ocean in less than a day.
Another important factor in considering tsunamis is the rate at which they lose energy. Because a wave loses energy at a rate inversely related to its wavelength, tsunamis can travel at high speeds for a long period of time and lose very little energy in the process.
Because of the small wave height a tsunami has during much of its journey through deep water, a reliable early detection system for tsunamis has yet to be developed. The Pacific Tsunami Warning Center (PTWC) in Hawaii is the regional operational center for tsunami information in the Pacific. Two types of bulletins are released to advise of a possible approaching tsunami, a Tsunami Watch Bulletin and a Tsunami Warning Bulletin.A Tsunami Watch Bulletin is released when an earthquake occurs with a magnitude of 6.75 or greater on the Richter scale.
A Tsunami Warning Bulletin is released when information from tidal stations indicates that a potentially destructive tsunami exists. Tidal stations record information about the water around them and issue a warning when characteristics of the sea begin to match those of a potential tsunami.
Unfortunately, this system is not very reliable. Seventy-five percent of all warnings issued since 1948 have been false. For example, Honolulu was evacuated in 1948 on a false alarm at a cost of more than $30 million dollars.
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