Kathianne
04-19-2008, 07:42 AM
Thursday morning at school, a couple of teachers were in my room before school started. Just the normal gossiping and talking about summer, etc. All the sudden one of them said, "Your cell is buzzing," but I didn't have my cell with me. We figured somehow my laptop must have been the cause. A few minutes later, a precariously staked pile of papers fell over and we started laughing, I said, "Gee, maybe it's an earthquake." Laughter.
Yesterday, (Friday) morning I'm sitting in the kitchen with my coffee and suddenly the table is 'dancing', ceiling fan swaying. Yep, that was the earthquake. Seems the ones here are a bit different than those in the West. Here's some not so reassuring information from AP:
http://news.yahoo.com/s/ap/20080419/ap_on_re_us/midwest_earthquake
Scientists say Midwest quakes poorly understood
By DAVID MERCER, Associated Press Writer1 hour, 43 minutes ago
Scientists say they know far too little about Midwestern seismic zones like the one that rumbled to life under southern Illinois Friday morning, but some of what they do know is unnerving.
The fault zones beneath the Mississippi River Valley have produced some of the largest modern U.S. quakes east of the Rockies, a region covered with old buildings not built to withstand seismic activity.
And, when quakes happen, they're felt far and wide, their vibrations propagated over hundreds of miles of bedrock.
...
The New Madrid fault zone produced a series of quakes in 1811 and 1812 that reached an estimated magnitude 7.0, putting them among the strongest known quakes to have occurred east of the Rockies. The quakes changed the course of the Mississippi River and were felt in New England.
That distance of well over a thousand miles sounds impressive, but experts say quakes that happen in the Midwest commonly radiate out for hundreds of miles because of the bedrock beneath much of the eastern United States.
"Our bedrock here is old, really rigid and sends those waves a long way," said Bob Bauer, a geologist with the Illinois State Geological Survey who works in Champaign.
He compared the underground rock, which in much of the Midwest lies anywhere from a few thousand feet to just a few feet below the earth's surface, to a bell that very efficiently transmits seismic waves like sound.
"California is young bedrock," he explained. "It's broken up ... like a cracked bell. You ring that, the waves don't go as far."
The question of whether Friday's quake was centered along a branch of the New Madrid zone or not is of more than academic interest. The area even now produces smaller, very regular quakes, and experts say it still has the potential to produce a quake that could devastate the region.
The Wabash faults have the potential to do the same, at least based on distant history, said Columbia University seismologist Won-Young Kim.
The strongest quake produced in recent history by the Wabash was a magnitude 5.3 in southern Illinois in 1968, but researchers have found evidence that 4,000 to 6,000 years ago, much stronger quakes shook the region, Kim said, as strong as magnitude 7.0 or more.
A similar quake is still possible, if the region is given time to build up enough energy, Kim said. But knowledge about the area is too thin to say whether that's likely, he added.
Yesterday, (Friday) morning I'm sitting in the kitchen with my coffee and suddenly the table is 'dancing', ceiling fan swaying. Yep, that was the earthquake. Seems the ones here are a bit different than those in the West. Here's some not so reassuring information from AP:
http://news.yahoo.com/s/ap/20080419/ap_on_re_us/midwest_earthquake
Scientists say Midwest quakes poorly understood
By DAVID MERCER, Associated Press Writer1 hour, 43 minutes ago
Scientists say they know far too little about Midwestern seismic zones like the one that rumbled to life under southern Illinois Friday morning, but some of what they do know is unnerving.
The fault zones beneath the Mississippi River Valley have produced some of the largest modern U.S. quakes east of the Rockies, a region covered with old buildings not built to withstand seismic activity.
And, when quakes happen, they're felt far and wide, their vibrations propagated over hundreds of miles of bedrock.
...
The New Madrid fault zone produced a series of quakes in 1811 and 1812 that reached an estimated magnitude 7.0, putting them among the strongest known quakes to have occurred east of the Rockies. The quakes changed the course of the Mississippi River and were felt in New England.
That distance of well over a thousand miles sounds impressive, but experts say quakes that happen in the Midwest commonly radiate out for hundreds of miles because of the bedrock beneath much of the eastern United States.
"Our bedrock here is old, really rigid and sends those waves a long way," said Bob Bauer, a geologist with the Illinois State Geological Survey who works in Champaign.
He compared the underground rock, which in much of the Midwest lies anywhere from a few thousand feet to just a few feet below the earth's surface, to a bell that very efficiently transmits seismic waves like sound.
"California is young bedrock," he explained. "It's broken up ... like a cracked bell. You ring that, the waves don't go as far."
The question of whether Friday's quake was centered along a branch of the New Madrid zone or not is of more than academic interest. The area even now produces smaller, very regular quakes, and experts say it still has the potential to produce a quake that could devastate the region.
The Wabash faults have the potential to do the same, at least based on distant history, said Columbia University seismologist Won-Young Kim.
The strongest quake produced in recent history by the Wabash was a magnitude 5.3 in southern Illinois in 1968, but researchers have found evidence that 4,000 to 6,000 years ago, much stronger quakes shook the region, Kim said, as strong as magnitude 7.0 or more.
A similar quake is still possible, if the region is given time to build up enough energy, Kim said. But knowledge about the area is too thin to say whether that's likely, he added.