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. THERE IS NO TSUNAMI WARNING
OR WATCH IN EFFECT.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
ORIGIN TIME — A 2341Z 28 MAY 2007
COORDINATES — A 7.1 NORTHA 166.4 WEST
LOCATIONA A A — A NORTHWEST OF CHRISTMAS ISLAND, KIRIBATI ISLANDS
MAGNITUDEA A — A 6.6
EVALUATION
A DESTRUCTIVE TSUNAMI WAS NOT GENERATED BASED ON EARTHQUAKE AND
HISTORICAL TSUNAMI DATA.
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.
Kai looked at Reggie. 'It doesn't seem like anything to be worried about.'
Normally Kai would consult with Harry Dupree, his second-in-command. Harry had taken a three-day holiday to Maui and wasn't due back until that night. Reggie and Kai were on their own, and although Kai was growing more comfortable with his responsibilities, he was still fairly new.
After the Asia tsunami, the previous director left for a position at NOAA headquarters in Washington coordinating the development of a worldwide tsunami warning system. Since it looked like it was going to take a lot of wrangling to get it up and running, they wanted to have more than an acting director at the PTWC, so naturally they looked for a replacement from the limited ranks of tsunami experts.
When Reggie had recommended Kai for the job, Kai's position as head of the University of Washington geology department's tsunami research center put him in the short list of candidates. From Kai's perspective, the job prospect had seemed perfect. He could move his career forward while still doing interesting research. Rachel had plenty of job opportunities at Honolulu hotels. And Kai could finally get out of Seattle's rainy climate and back to warm, sunny Hawaii.
'No, it shouldn't be anything to worry about,' said Reggie. 'The event was not tsunamigenic.' Meaning it couldn't generate a tsunami. The statement was made as a fact, not an opinion.
'You seem pretty confident.'
Reggie smiled. He always smiled when he was about to explain something that was perfectly obvious to him. 'One, it barely triggered the alarms. The reading was just 6.6. A couple of ticks down and we wouldn't have even sent the bulletin.'
'Remember the Asia tsunami?' Kai said. 'The initial readings on that were 8.0. It ended up being a 9.0.' Because the moment magnitude scale for earthquakes-a successor to the Richter scale-is nonlinear, the power of an earthquake goes up exponentially the higher it is on the scale: an earthquake measuring 9.0 releases over 30 times more energy than an 8.0 earthquake.
'I'm just checking with NEIC now, but I don't see it going up much.' The seismic equipment at the National Earthquake Information Center monitored data readings from stations around the world, allowing them to determine the location of an earthquake to within 100 meters.
'Two,' Reggie continued, 'the seismic wave patterns suggest a strike-slip event.' Strike-slip faults move sideways instead of vertically. Vertical displacements of the ocean floor cause most tsunamis, like the one that had struck South Asia in 2004.
'Three, it's in an area that has never generated a tsunami. That's actually why I called you,' said Reggie. 'Look at this.' He pointed at the computer monitor.
The screen showed a map of the central Pacific with a blue dot pinpointing a position 500 miles northwest of Christmas Island, southwest of the Palmyra Atoll. The color blue meant that the quake was located near the earth's surface.
'What's the distance from here?'
'About 2000 kilometers,' said Reggie. A little more than 1200 miles.
Kai did the quick mental calculation in his head that was second nature to all tsunami scientists. Since all tsunamis traveled at approximately 500 miles per hour in open ocean-about the speed of a jet airliner-it was easy math. But before Kai could speak, Reggie handed him a printout.
'Already got it.'
The printout showed a list of station names and codes of all of the tide gauges in the Pacific Ocean. Next to each station name was a latitude, longitude, and the estimated arrival time for the potential tsunami.
'Looks like that gives us between two and two and a half hours.'
'I'm predicting we'll barely see a tide change,' said Reggie. 'The tide sensor at Christmas Island will tell us for sure.'
Kai looked back at the printout. Any wave generated by the event would reach Christmas Island in about 35 minutes.
'Hand me the tide gauge schedule,' he said.
Most of the tide gauges would transmit their readings to a satellite, which then got relayed to the PTWC. Although the gauges were cheap to produce and monitored tide levels 24 hours a day, their main drawback was that they only sent the tide level data once an hour.
Kai scanned the list to find Christmas Island. The next transmission would be only five minutes after the wave was supposed to arrive there.
'Show me the earthquake map.'
Reggie clicked on the appropriate icon, and colored dots bloomed on the map around the blue dot. The colored circles showed the depth of seismic events around the Pacific Rim, with the different colors representing the depths of the events. A few red stars punctuated the map, showing where tsunamis had started. None of the stars was located within 500 miles of the blue dot.
'That area has never even had an earthquake,' Kai said.
'Weird, huh?'
Most tsunamigenic quakes occur where continental plates smash together, such as along the coasts of Alaska, Chile, and Indonesia. But shallow quakes are usually associated with plates slipping past each other, the most famous of which is the San Andreas fault in California.
'That area of the ocean floor is not very well-mapped,' Reggie said. 'I'd guess one of two things. First, it could be a fault that we've never detected before.'
'Highly unlikely.'
'Right. But second, and this is pretty exciting, it could be a new seamount. That would explain why it's so shallow.'
Now Kai understood Reggie's excitement. A new seamount was a rare phenomenon, essentially the birth of a new island. An underwater volcano erupted over a magma hot spot on the ocean floor, building a mountain around itself and regularly unleashing earthquakes in the process. If the seamount got high enough, it broke through the surface of the water, which is exactly how the Hawaiian Islands were formed and were still forming, as the continual eruption of Kilauea on the Big Island spectacularly demonstrated.
If this event did turn out to be a seamount, Reggie would get the credit for discovering it. To a geophysicist, it was the closest thing to an astronomer finding a new comet.
'Congratulations,' Kai said. 'If it turns out to be a new seamount, you'll get journal articles out of it for the next five years.'
'Damn straight.' Reggie winked. 'If you're good to me, I might have room to put you as second author.'
'Your generosity is overwhelming.' Reggie let out a huge belly laugh at that. 'But before we start celebrating,' Kai continued, 'let's make sure that we're not dealing with a tsunami here. You're doing the usual?'
'Other than figuring out a name for my seamount,' Reggie said, 'I'm working with the NEIC to pinpoint the
