The purpose of this research is to evaluate the use of passive seismic methods to estimate the depth to bedrock. These seismic investigations are used to delineate different geologic conditions such as layer geometry, water table, and the bedrock topography. Civil engineers rely on accurate measurements and assessments of bedrock to build safe, stable structures. The goal of the project is to establish the accuracy and efficacy of these methods as compared to current and historic core boring taken by PennDOT, with the goal being to eliminate a portion of the core borings currently being performed by the Department. Fourteen sites across northwestern Pennsylvania were used to evaluate the results from 3 different methodologies to historical core borings with recommendations provided.