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Originally published September 12, 2006
Gators, storms, heat and now this?
Rare earthquake hits the Tallahassee area
By Gerald Ensley
DEMOCRAT SENIOR WRITER
When the first tremor hit Sunday morning and the four-story building in the Winewood Office Complex started swaying, the 18 people working the phones of the Florida Abuse Hotline looked nervously at each other. One person suggested it was a sonic boom - then another said she felt nauseated.
That rang a bell with supervisor Bill Edwards, who recalled a show on the Discovery Channel explaining that the motion of an earthquake often nauseates people.
Five seconds later, when a second tremor hit, Edwards ordered everyone to evacuate their fourth-floor office. And he called 911.
"It was like a rock thrown in a pond, causing three separate ripples," Edwards said of each tremor. "I had no idea what this building was made to withstand, and I thought there was a chance things could get worse. So I said, 'Let's get outside and figure this out.' "
That was a smart move. Tallahassee experienced a rare earthquake Sunday.
The quake occurred at 10:56 a.m. in the Gulf of Mexico, about 250 miles south of Apalachicola. It registered a 6.0 on the Richter scale, which qualifies as a "strong" earthquake. Quakes of 7.0 or greater are considered "major."
This one was felt throughout Florida and the Southeast. As of Monday, a dozen people in Leon and Wakulla counties had registered on the U.S. Geological Survey Web site (www.earthquake.usgs.gov) to say they had felt the earthquake. All the local reports listed the tremors as "weak" or "light."
This was a "midplate" earthquake, meaning pressure under the middle of the North American tectonic plate caused buckling of the ocean floor. The most severe earthquakes occur at the boundaries of two plates, such as the western edge of the North American plate, which runs through earthquake-heavy areas such as California and Alaska.
Sunday's earthquake was not strong enough to cause a tsunami, or tidal wave, which generally requires an earthquake with a magnitude of 7 or greater. The calamitous December 2004 tsunami in Southeast Asia was produced by an earthquake of 9.1.
Each digit increase on the Richter scale represents a 10-fold increase in an earthquake's strength. The 2004 earthquake in Southeast Asia was 1,000 times stronger than Sunday's in the Gulf.
"This one was simply not big enough (for a tsunami)," said Don Blakeman, a geophysicist with the National Earthquake Information Center in Golden, Colo. "I don't know of one in the Gulf that's ever been big enough."
It was the second earthquake in the Gulf of Mexico this year. On Feb. 10, an earthquake of 5.2 magnitude occurred in roughly the same area. In October 2004, a Gulf quake measured 4.4.
Yet Blakeman said there's no reason for alarm. He said there've been only about a dozen earthquakes in the Gulf over the past 40 years. By contrast, there are 30,000 around the world each year.
"The Gulf is very seismically quiet compared to Japan, Indonesia and Alaska," Blakeman said. "The one in February and this one were the biggest in 30 years. But I don't think it can be construed as anything more (unusual) than that."
Even so, University of Florida geology professor Ray Russo would like to see Florida increase its earthquake-detection capabilities.
There are 500 to 600 earthquake-detection stations around the world. All of them can (and did) detect earthquakes as big as Sunday's. Florida has only three or four detection stations because of its low frequency of earthquakes.
But Russo submitted a proposal to the Legislature last spring for $540,000 to fund eight more detection stations for 10 years around the state. Russo said a network of stations would allow an alarm to be broadcast sooner should a major earthquake or tsunami hit the state. He said the warning time would be only about 10 minutes - but enough time for people to evacuate buildings or get away from the shore.
"People think the Gulf is a quiet place for earthquakes, but now a magnitude-6 opens the door for reconsidering," Russo said. "There is no way to answer the question of whether we'll have another. But if we do, we ought to have an idea of the possible consequences and have something in place."
You can register your experience with Sunday's earthquake, or any future earthquakes, on an Earthquake Hazards Program Web site operated by the U.S. Geological Survey at www.earthquake.usgs.gov. Click on "Magnitude 6.0 Gulf of Mexico, Sept. 10, 2006," then click on "MAPS" and "Tell Us." The USGS encourages people to register after an earthquake even if they felt nothing so scientists can map the severity in each area. To view responses to Sunday's earthquake, click on "Did You Feel It" under the MAPS icon.
Originally published September 12, 2006
Gators, storms, heat and now this?
Rare earthquake hits the Tallahassee area
By Gerald Ensley
DEMOCRAT SENIOR WRITER
When the first tremor hit Sunday morning and the four-story building in the Winewood Office Complex started swaying, the 18 people working the phones of the Florida Abuse Hotline looked nervously at each other. One person suggested it was a sonic boom - then another said she felt nauseated.
That rang a bell with supervisor Bill Edwards, who recalled a show on the Discovery Channel explaining that the motion of an earthquake often nauseates people.
Five seconds later, when a second tremor hit, Edwards ordered everyone to evacuate their fourth-floor office. And he called 911.
"It was like a rock thrown in a pond, causing three separate ripples," Edwards said of each tremor. "I had no idea what this building was made to withstand, and I thought there was a chance things could get worse. So I said, 'Let's get outside and figure this out.' "
That was a smart move. Tallahassee experienced a rare earthquake Sunday.
The quake occurred at 10:56 a.m. in the Gulf of Mexico, about 250 miles south of Apalachicola. It registered a 6.0 on the Richter scale, which qualifies as a "strong" earthquake. Quakes of 7.0 or greater are considered "major."
This one was felt throughout Florida and the Southeast. As of Monday, a dozen people in Leon and Wakulla counties had registered on the U.S. Geological Survey Web site (www.earthquake.usgs.gov) to say they had felt the earthquake. All the local reports listed the tremors as "weak" or "light."
This was a "midplate" earthquake, meaning pressure under the middle of the North American tectonic plate caused buckling of the ocean floor. The most severe earthquakes occur at the boundaries of two plates, such as the western edge of the North American plate, which runs through earthquake-heavy areas such as California and Alaska.
Sunday's earthquake was not strong enough to cause a tsunami, or tidal wave, which generally requires an earthquake with a magnitude of 7 or greater. The calamitous December 2004 tsunami in Southeast Asia was produced by an earthquake of 9.1.
Each digit increase on the Richter scale represents a 10-fold increase in an earthquake's strength. The 2004 earthquake in Southeast Asia was 1,000 times stronger than Sunday's in the Gulf.
"This one was simply not big enough (for a tsunami)," said Don Blakeman, a geophysicist with the National Earthquake Information Center in Golden, Colo. "I don't know of one in the Gulf that's ever been big enough."
It was the second earthquake in the Gulf of Mexico this year. On Feb. 10, an earthquake of 5.2 magnitude occurred in roughly the same area. In October 2004, a Gulf quake measured 4.4.
Yet Blakeman said there's no reason for alarm. He said there've been only about a dozen earthquakes in the Gulf over the past 40 years. By contrast, there are 30,000 around the world each year.
"The Gulf is very seismically quiet compared to Japan, Indonesia and Alaska," Blakeman said. "The one in February and this one were the biggest in 30 years. But I don't think it can be construed as anything more (unusual) than that."
Even so, University of Florida geology professor Ray Russo would like to see Florida increase its earthquake-detection capabilities.
There are 500 to 600 earthquake-detection stations around the world. All of them can (and did) detect earthquakes as big as Sunday's. Florida has only three or four detection stations because of its low frequency of earthquakes.
But Russo submitted a proposal to the Legislature last spring for $540,000 to fund eight more detection stations for 10 years around the state. Russo said a network of stations would allow an alarm to be broadcast sooner should a major earthquake or tsunami hit the state. He said the warning time would be only about 10 minutes - but enough time for people to evacuate buildings or get away from the shore.
"People think the Gulf is a quiet place for earthquakes, but now a magnitude-6 opens the door for reconsidering," Russo said. "There is no way to answer the question of whether we'll have another. But if we do, we ought to have an idea of the possible consequences and have something in place."
You can register your experience with Sunday's earthquake, or any future earthquakes, on an Earthquake Hazards Program Web site operated by the U.S. Geological Survey at www.earthquake.usgs.gov. Click on "Magnitude 6.0 Gulf of Mexico, Sept. 10, 2006," then click on "MAPS" and "Tell Us." The USGS encourages people to register after an earthquake even if they felt nothing so scientists can map the severity in each area. To view responses to Sunday's earthquake, click on "Did You Feel It" under the MAPS icon.
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