2008 Illinois earthquake

2008 Illinois earthquake

Date	April 18, 2008 (2008-04-18)
Magnitude	5.4 Mw
Depth	11.6 kilometers (7.2 mi)
Epicenter	38°27′N 87°53′W / 38.45°N 87.89°W / 38.45; -87.89Coordinates: 38°27′N 87°53′W / 38.45°N 87.89°W / 38.45; -87.89 Lick Prairie Precinct, Wabash County, Illinois (5 miles north-northeast Bellmont, Illinois)
Areas affected	United States
Max. intensity	VII - Very strong[1]
Casualties	2 injuries

The 2008 Illinois earthquake was one of the largest earthquakes ever recorded in the state of Illinois, measuring a magnitude of 5.4.^[2] It occurred at 4:37:00am CDT (9:37:00 UTC) on April 18 within the Wabash Valley Seismic Zone at a depth of 11.6 km. It was centered near West Salem, Illinois and Mount Carmel, Illinois (the affected area is west of Terre Haute, Indiana and Vincennes, Indiana; east of St. Louis, Missouri; and northwest of Evansville, Indiana), specifically 38.450°N, 87.890°W,^[3] and felt as far as 450 miles (724 km) away.^[4] Tremors were felt as far west as Nebraska^[5] and Kansas City,^[6] as far south as Atlanta,^[7] as far east as Kitchener, Ontario^[8] and West Virginia,^[9] and as far north as the Upper Peninsula of Michigan.^[10] The earthquake was felt so far away, compared to earthquakes in other regions, because the old, rigid bedrock beneath much of the Midwest allows the tremor to propagate further.^[5][9]

The earthquake epicenter was located in the Wabash Valley Seismic Zone, which is adjacent to the more famous New Madrid Seismic Zone.^[11]

Damage

• In Mount Carmel, Illinois, a woman was trapped in her home by a collapsed porch but was quickly freed and was not hurt. Also, an old school that was converted into a two-story apartment building was evacuated because of loose and falling bricks and because the roof had started to collapse into a couple of the apartments on the top floor.^[12] The building was later condemned.^[13] A man received serious eye injuries, but did not seek immediate medical attention.^[13]

• In St. Louis, Missouri, the outer lanes on the South Kingshighway Boulevard viaduct were closed between Shaw Boulevard and South Vandeventer Avenue/Southwest Avenue for approximately thirty minutes because pieces of concrete were seen around it, and on the surface streets/railroad tracks below it.^[14] Several chimneys collapsed in South St Louis, and the St Francis De Salles Oratory Roman Catholic Parish reported damage to its steeple, and the Basilica of St Louis King of France reported small fragments from the mosaic ceiling. Following the quake, 35,000 people in St Louis County were with out power, as the Labadie Power Station went offline due to strong vibrations. Power was restored by 9:46 AM

• In Louisville, Kentucky, a facade broke off from an older building just south of downtown.^[15]

• In Harrison County, Indiana, across the Ohio River from Louisville, the riverboat casino Caesars Indiana lost power.^[15]

• In Princeton, Indiana, a woman was cut when a crystal figurine was knocked from a shelf in her home.^[16]

• Illinois and Kentucky state highway crews were investigating if any roads or bridges were damaged in the area nearest the quake, only cracks had been reported on U.S. Route 51 near Cairo, Illinois, at the state's southern tip, said Mike Claffey, a spokesman for the Illinois Department of Transportation.^[17] No roads were reported to be damaged in Kentucky, but inspections were being conducted in the Louisville, Paducah, and Henderson districts, according to the Kentucky Department of Transportation.^[18]

• Unit 4 at Gibson Generating Station automatically shut down after the earthquake due to its vibration sensors.^[19]

Emergency response

Many precautionary measures were taken after the initial quake, including several evacuations.^[20] All Vincennes University dormitories were evacuated as a precaution, but no damage was discovered and students were allowed to return after about 45 minutes. A coal mine in Gibson County, Indiana, was also evacuated after the earthquake, but miners returned to work shortly afterwards.^[21]

The Gibson County, Indiana, 9-1-1 system was briefly knocked offline due to a flood of calls resulting from the earthquake, but after about 15 minutes service was restored.^[21]

Aftershocks

A week after the main earthquake, the USGS recorded a total of 26 aftershocks ranging in magnitude from 1.0 to 4.6. The biggest aftershock occurred at 10:14am CDT (15:14 UTC),^[11] on April 18; it was a magnitude 4.6, and also centered near West Salem, just north of the original quake.^[22][23] An aftershock with a magnitude of 4.0 (initially reported as 4.5) was felt three days later on April 21, at 12:38am CDT (05:38 UTC), centered northwest of Mt. Carmel, Illinois.^{[24] [25]} A 3.7 aftershock struck on Friday, April 25 around 17:30 GMT (12:30 PM CDT).^[26] A 3.3 aftershock struck on Thursday, May 1 around 5:30 GMT (12:30 AM CDT). ^[27] A 3.6 aftershock struck on Thursday, June 5 around 2:13 AM local time.^[28]

Earthquake on TV

Several television stations were live on-air when the quake hit. CBS 8 WISH-TV in Indianapolis, NBC 14 WFIE^[29] in Evansville and WAVE 3^[30] and WHAS 11^[31] in Louisville were doing local news broadcasts when the tremors hit.

Tremors of the magnitude 4.6 aftershock were also caught on camera during a taped interview with the Indiana Department of Transportation in Vincennes, Indiana, as the interviewer asked about the magnitude 5.4 earthquake. It was later broadcast on the Wabash Valley's local news station WTWO's Live at Five broadcast.^[32][33]

See also

• 1968 Illinois earthquake
• List of earthquakes in Illinois

References

External links

Wikinews has related news: Minor earthquake shakes Illinois

• "Map showing area". USGS. Archived from the original on 22 April 2008. Retrieved 2008-04-18. 
• "Information on this specific earthquake". USGS. Archived from the original on 11 May 2008. Retrieved 2008-05-04. 
• "Seismographic Readings for this specific earthquake" (PDF). Illinois State Geological Survey. Archived (PDF) from the original on 12 May 2008. Retrieved 2008-04-18. 
• "Seismographic Readings for 15:15 (UTC) aftershock" (PDF). Illinois State Geological Survey. Archived (PDF) from the original on 12 May 2008. Retrieved 2008-04-18. 
• Last event for Illinois. USGS. Preliminary earthquake report for the latest aftershock