Acquisition of Control Points Throughout Indiana for Accurate Calibration of the Tromino Geophone

Status Start Date End Date Locations
completed Dec 15, 2018 Feb 15, 2020 Adams, Blackford, Cass, Howard, Johnson, Lagrange, Miami, Monroe, Morgan, Noble,
St Joseph, Steuben
Director: Don Tripp
Other Researchers: Robin Rupp
Funding: Indiana University - Indiana Geological & Water Survey
Issue: There are limited numbers of Tromino control points in the state of Indiana. For example, Monroe County has no control points and therefore points from Bartholomew County have been used for calibration. The issue is that the geology will vary and thus the frequencies that indicate depth to bedrock in one region may be different in another region, dictated by the geology of those areas.
Objective: Our objective is to create a data base which will contain the frequencies for depth to bedrock throughout the state of Indiana. This would allow researchers to be able to properly create calibration curves that are specific to the region where research is being conducted. This would facilitate more accurate interpretations of data collected using the Tromino during research conducted by the survey. Data could be accessible by academic and/or industry researchers as a service provided by IGWS.
Approach: A shapefile downloaded from the DNR web site will be used as our primary source for well locations with known depths to bedrock. The shapefile will be filtered so that the most recent 35 water wells that have been field located can be identified as our primary target wells. Additionally, as best as possible we will select a broad range of depths within each county in order to facilitate better calibration curves. We also have IGWS drill holes and gamma logs that we can use to augment the water wells identified from the DNR shape file. 1) We will start off by gathering control points in Monroe County to support ongoing research being conducted by Henry Loope and Peter Jacobs in Flatwoods Park and Bean Blossom Valley. This would also serve as a pilot in order to further constrain costs associated with collecting control points. 2) Based upon Jose Luis’s needs, the next counties would be the NW portion of Morgan County and Johnson County. 3) Additional control points are needed in Lagrange, Noble, Steuben Counties. Due to the distance, control points could be collected in these counties concurrently with other field operations as they happen in order to reduce cost. a. Jose Luis stated that he would like to have this northern region complete within the next 1 ½ years. 4) Additional control points to be taken would be in the Teays Valley region (Blackford and Adams Counties).
Products: Shapefiles that contain as a minimum the locations of all wells, drill holes, and gamma logs used for this project along with depths to bedrock and frequencies. Data base containing frequencies to depth will be located on Z:\Tromino\Database
Benefits: The benefits of this study would be that we could potentially have a data base that users can pull from in order to make proper and accurate calibrations for the Tromino that is specific to a given region. Currently we have a low density of calibration points throughout the state. Ultimately we would like to have a statewide comprehensive data base that user could pull from regardless of which part of Indiana they would be working in and be able to produce accurate calibration curves.