Team participates in project to explore Earth's interior

A University of Northern Iowa geologist and two of his students are taking part in a National Science Foundation project to explore the formation, structure and evolution of the North American continent.            
   
James Walters, professor and head of the Department of Earth Science, and May 2009 UNI geology graduates Rodney Hubscher of Marion and Drew M. Kreman of Tipton are spending 10 weeks this summer locating optimal sites in Iowa where seismometers can be installed.The USArray project, part of the decade-long EarthScope experiment, is placing hundreds of permanent and portable seismometers, which measure the actual movement of the ground across the continental U.S., according to Walters. With the data from this network, researchers will be able to collect detailed images of the Earth’s interior and investigate the processes controlling earthquakes and volcanoes.
   
Begun in California in 2004, the project is now east of the Rockies. This summer teams are fanning out across Iowa, Minnesota, Missouri, Arkansas and Louisiana to locate appropriate sites, preferably remote and secluded. “Our ideal site is in secluded pasture land, along a fence. This seems to be no problem for most of the landowners we have asked permission from,” said Kreman. The seismic stations are placed about 45 miles apart in a grid-like configuration and remain on-site for two years.
   
Each seismic station is housed in a dome-capped steel cylinder, about the size of a basketball, which is buried sitting atop about four inches of concrete to prevent it from floating to the surface in water-logged ground. Solar panels above ground provide power, and cell phone modems relay the seismometer data.
   
The data consist of plots of sound waves, arriving from all directions. Combining these plots gives scientists information on what lies beneath Earth’s surface. “How sound waves weaken, refract and twist within the Earth varies according to the temperature, pressure and composition of the rocks they pass through,” Walters explained. “By determining the time it takes vibrations to travel from one place to another, scientists can figure out the nature of the material along that path.”
   
Walters’ students, who attended a four-day training session at the University of Minnesota in May, are surveying target areas, getting permission from landowners and staking the sites. “Many of the Iowa farmers hosting these sites plan on using the stations as educational portals for their children and community schools,” Hubscher noted. “Students will be able to monitor the station live, and EarthScope provides educational materials to supplement the learning experience.” During the summer of 2010, the seismometers will be installed.
Both students have found Iowa farmers to be easy to work with and also that their association with UNI has helped. “I felt really proud representing the University of Northern Iowa,” said Kreman. “This is a great opportunity for the students to get some hands-on experience in the field,” said Walters.
   
Hubscher will attend San Diego State University in the fall, where he will begin a master of science degree in geology. Kreman will attend the University of Arkansas, where he will pursue a master’s degree in the geosciences.

 

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