ISGS - April 2008 Activity Highlights

1904 Berry School, Mt. Carmel, Illinois
showing the collapsed chimmey and bricks missing.

April 18, 2008, Mt. Carmel, Illinois: Magnitude 5.2 Earthquake and Aftershocks

At 4:37 a.m. on April 18, 2008, Illinois experienced a 5.2 magnitude earthquake. The earthquake was felt in 18 states. The epicenter of the earthquake was located about six miles northwest of Mt. Carmel, Illinois, and was located in the Wabash Valley Seismic Zone. This area was the location of previous magnitude 5 earthquakes in 1968 and 1987. The 1968 magnitude 5.3 earthquake was the largest recorded in the central United States since 1895. On the day of the quake, members of the Illinois State Geological Survey (ISGS) participated in many roles to provide information to the Governor's Office, Illinois Emergency Management Agency (IEMA), and the public through approximately 20 press interviews and continuous updates to the ISGS Web site. ISGS staff coordinated deployment of portable recording seismographs near the main shock epicenter by representatives of the Center for Earthquake Research and Information, University of Memphis, and Indiana University. The damage in towns within about 30 miles of the earthquake was documented. Over two dozen magnitude 1.0 or greater aftershocks have been recorded, and ISGS staff continue to monitor these events and communicate information to the public.

The ISGS had a staff member at the State Emergency Operations Center in Springfield who helped write several press releases for the Governor's Office and IEMA. Text was also provided for the IEMA and Homeland Security Web sites. Additionally, ISGS staff, the IEMA director, and a representative from the Department of Insurance participated in the State's press conference. Historical earthquake information about the area of the earthquake and expectations for aftershocks were also communicated to the representatives in the State Emergency Operations Center.

Damage in Illinois was recorded by two ISGS geologists on the day of the main shock. The geologists documented the nonstructural damage to chimneys, parapets, grave markers, and television antennae in many towns in roughly a 30-mile radius of the epicenter. They documented one building where brick walls fell inward, causing the apartment building to be condemned. (Contacts: Bob Bauer and Tim Larson)

Participants in the geological science field trips.

Spring Geological Science Field Trips Popular with Participants

Approximately 100 people attended the Illinois State Geological Survey spring Geological Science Field Trips on April 25, and May 31, 2008. The field trips highlighted the geology and natural resources of the Horseshoe Lake State Conservation Area and surrounding areas and included six stops within Alexander County.

The first field trip stop was south of Miller City at the base of the Santa Fe Levee. There participants viewed the landscape changes that occurred following the levee breach during the Great Flood of 1993. The second stop was to an Eocene age sand and gravel deposit within Black Powder Hollow, south of Thebes, where a large number of participants collected a variety of agates. The third stop was Rock Springs Hollow, where the Ordovician age Girardeau Limestone is bounded by a number of faults and related fractures that have created a series of small waterfalls. Following lunch at Horseshoe Lake, the participants learned that this oxbow lake formed approximately 6,000 years ago when the Mississippi River changed course, cutting off a large meander. The fourth stop, to the Olive Branch-Sandy Ridge Novaculite Quarry, provided an excellent view of the ancient Ohio River valley and an opportunity to discuss the geological history of the Ohio River, its abandonment of its former course through what is now the Cache Valley during the last glaciation, and its present course. The participants were able to view a large fault within the quarry and collect a number of loess kindchen(unusually shaped calcareous concretions) that form in the overlying windblown loess deposits. The fifth stop was Birk-McCrite tripoli quarry, operated by Unimin Speciality Minerals Inc. The participants learned about the quarry operation and the uses of tripoli, a microcrystalline silica. Some of the more common uses of tripoli include buffing and polishing compounds and use as a filler and extender in plastics, paints, and rubber. The participants collected Devonian age fossils and a variety of mineral specimens at this quarry. The final stop on the trip was to the Tatumville Novaculite Quarry, where participants examined a rare exposure of a graben (a downthrown block of bedrock bounded by two faults) within the quarry highwall and collected samples of novaculite, a microcrystalline chert. Novaculite is typically used as a base for road construction and also as a fine sharpening stone. As the day came to an end, ISGS geologists spent time answering a number of questions from individual participants. A question on a number of minds, given the number of faults seen on the field trip, concerned the recent 5.2 earthquake in southern Illinois and its relationship to the New Madrid Seismic Zone. (Contact: Wayne Frankie)

Thick (11 m) Peoria Silt loess near Owensboro being studied to correlate the paleosols (dark bands) with similar loess-paleosol sequences in southern Illinois. The loess shown was deposited between about 25,000 and 11,000 years ago during the Wisconsin Episode of glaciation.

ISGS Researchers Active at North-Central GSA

Four ISGS geologists co-led two field trips for the North-Central Geological Society of America (GSA) meeting in Evansville, Indiana. Thirty people from Maryland, Ohio, Pennsylvania, Nebraska, Missouri, Iowa, Indiana, and Kentucky attended the first trip, which covered the Illinois-Kentucky Fluorite District in southern Illinois and northwestern Kentucky. One of the trip highlights was the stop at the Hastie Mining Company quarry, the only place in Illinois where fluorite is currently mined as a by-product of the limestone quarry operation.

The second field trip, "From the Cincinnati Arch to the Illinois Basin, Geological Field Excursions along the Ohio River Valley", was organized by the Pander Society, a group of conodont enthusiasts organized in 1967. The society takes its name from the German scientist C.H. Pander, who in 1856 was the first to describe these enigmatic fossils. Conodonts are of great value in biostratigraphy, particularly in Silurian through Pennsylvanian age rocks. Conodonts undergo successive color changes with temperature of burial and can be used as an index to rank or maturation of hydrocarbon-bearing rock. The field trip visited four sites where conodonts are known to occur in Pennsylvanian rocks of southwestern Indiana. These sites were an outcrop of the Lead Creek Limestone, a surface coal mine showing Middle Pennsylvanian coal-bearing rocks, a box cut serving as the portal to an underground mine where Middle Pennsylvanian rocks are exposed, and the type outcrop of the West Franklin Limestone. The field trip was co-led by a retiree from the Indiana Geological Survey and a coal geologist who works as a consultant for Marshall Miller Co. in Evansville. For this trip, an ISGS geologist led the stop that discussed aspects of Pennsylvanian stratigraphy, sedimentation, and conodonts in southwestern Indiana. These two field trips were the only two trips at this year's North-Central GSA that were fully booked.

In addition to the field trips, ISGS staff members were co-authors of numerous abstracts presented at the meeting. (Contacts: Brett Denny and Don McKay)

Landslide Investigated

An earth slump landslide occurred within materials on a bench of limestone bedrock in Grafton, Illinois. An ISGS engineering geologist responded to a request to evaluate the setting for the Illinois Emergency Management Agency (IEMA), since the Grafton mayor closed State Route 100 until the threat of potential landslide onto the road was assessed. Material from high on the slope flowed down the slope, as did the thin soil on the bedrock face below the bench. Part of the lower part of the slide pressed up against the back of a house. The geologist supplied information to the city engineering firm and IEMA regarding the setting, diagrams, and borehole information and provided a list of possible mitigation issues to investigate.

The engineering geologist also provided pictures, locations, and descriptions of Illinois landslides to the U.S. Geological Survey Landslide Center after their staff saw press coverage of the Grafton landslide. Among the described images was a rock fall event along the Mississippi river north of Savanna and historic pictures of rock slumps in the same area in the 1920s. Also, landslides that damaged houses west of Peoria, Illinois, were provided.

While mapping in Calhoun County, Illinois, for the STATEMAP program, two ISGS geologists visited a landslide located on a property just below Tara Point Inn in Grafton, Illinois. A scarp developed in the Hannibal Shale, which is about 50 to 60 feet thick in this area of the Grafton Quadrangle and overlies Silurian age dolomite. A perched groundwater table, due to a large amount of rainfall and a small pond, contributed to the slide. Jointing of the carbonate rocks above the Hannibal Shale yielded a lot of water, which further exaggerated the slump. The Hannibal Shale can turn into a greenish claystone and become very unstable. (Contact: Bob Bauer)

Fabrication of a Full-Scale Sorbent Activation Process for Mercury Control

Chemical engineers from the Illinois State Geological Survey (ISGS) worked with engineers from Apogee Scientific, Inc., EPRI, and Maxwell Consultant and Engineering to design a full-scale sorbent activation process (SAP) unit. The SAP unit will be used for on-site production of activated carbon from Illinois coal at Ameren's Meredosia power plant during September through December 2008. The Engineering design data were obtained from the Applied Research Laboratory at the ISGS using a bench-scale SAP unit. ISGS engineers are currently providing technical assistance to Heat Transfer Specialists, Pekin, Illinois, to fabricate the SAP unit. A meeting is planned for May 22, 2008, at Meredosia to discuss the planned full-scale mercury control tests. SAP is a state-of-the-art, patented technology developed at the ISGS. This one-of-a-kind technology is expected to reduce the cost of mercury control removal from coal power plants by more than 50%. (Contact: Massoud Rostam-Abadi)

Highlights Archive

Updated 07/23/2012 SLD