Engineering Geology is the branch of science that applies geologic knowledge to civil works design. It involves reviewing geologic data, such as maps, reports and aerial photos, conducting site surveys and geologic mapping, exploring the subsurface conditions, and monitoring ground movements with instruments. Engineering Geology also evaluates critical factors for slope stability, seismicity, fault activity, ground water behavior, and environmental impacts. When the soil conditions are unfavorable, Engineering Geologists provide relevant geologic information to Geotechnical Engineers for designing soil improvement methods, such as shear pins, dewatering, underpinning, grouting and stabilization fill.