Abstract:
A project involving computer analysis is proposed to test the feasibility of doing field gravity surveys of Blackford and surrounding counties. The method of obtaining the analytical data for this project will be as follows: First, the author will write a computer program that will compute the gravity variations along different cross sections of a model of a glacially buried river valley. Next, the author will employ the program to compute changes in the expected gravity profile relevant to changes in density values of the substrata and varying dimensions for the model river valley. The computed profiles will be used to evaluate the resolving power of the gravity survey in delineating subsurface geometry. This data can be cross evaluated with available seismic data to test the validity of the gravity method. The data obtained will permit discussion of the theoretical gravity map patterns in Blackford and surrounding counties. This study is significant for several reasons. Gravity evaluations of this sort may be a tool for evaluating buried river valleys as a groundwater resource for the future. This possibility could have great economic value, if not here, perhaps in other areas of similar conditions.The data from this survey is also usable to evaluate other local glacial subsurface conditions. The author will test the sensitivity of a gravity survey to determine the degree of accuracy with which one can locate buried, smaller tributaries leading from the main stream and to see how accurately one can estimate the overall slope of the buried river valley itself.Finally, the project will test the feasibility of future actual gravity field surveys which may save large amounts of time and energy.