Shragge, JeffreyWilson, Gavin2022-10-142022-10-142022https://hdl.handle.net/11124/15432Includes bibliographical references.2022 Spring.Climate change, expanding populations, and the rapid industrialization of low and middle income countries have created unprecedented challenges for local communities and their surrounding environments. Near-surface geophysical surveying can provide a wealth of data to help address these challenges in a cost-effective manner that is minimally invasive to local environments. Electrical and electromagnetic methods are two such families of techniques that are widely used in near-surface geophysics due to their wide applicability to near-surface problems, such as water exploration and environmental monitoring, the ease of data acquisition, and that electrical and electromagnetic geophysical data can greatly aid near-surface investigations with minimal processing. Recent development and the widespread availability of electrical components and cheap microcomputers have created new opportunities for developing purpose-built, low-cost, open-source geophysical instrumentation for near-surface investigation. This thesis reports the development of two such prototype instruments. First, a frequency-domain instrument that is capable of sensing conductive objects in near-surface environments and costing under US$400 has been designed and validated at the Colorado School of Mines. Second, a time-domain induced polarization instrument, based off an existing low-cost direct current resistivity meter system, was developed and validated in a laboratory setting. The induced polarization system is capable of sensing highly chargeable objects, such as sulfides, and costs under US$200 to construct. Both instruments have demonstrated the capability to be leveraged for near-surface humanitarian applications. Future development includes improving on the mechanical stability of the low-cost instrumentation and improving autologging capabilities for use in remote and time-lapse geophysical investigations.born digitalmasters thesesengCopyright of the original work is retained by the author.electromagneticsgeophysicsinduced polarizationinstrumentationlow-costnear-surfaceText2022-10-01