Applied Geology
Applied Geology tests how geological knowledge is used in engineering, groundwater, hazard assessment and exploration.
Groundwater
- Aquifer: porous and permeable; aquiclude: porous but impermeable; aquifuge: neither.
- Water table, confined aquifer, artesian well, cone of depression, porosity versus permeability.
Engineering geology
- Dam sites need impermeable, competent rock; avoid faults, soluble limestone and landslide zones.
- Tunnels are favourable in massive igneous and metamorphic rock; difficult in swelling clays and fault zones.
- Landslides occur on steep slopes with weak rock and high water pressure.
Exploration
- Geophysical: seismic reflection and refraction, gravity, magnetic, electrical resistivity.
- Geochemical: stream sediment and soil surveys.
- Remote sensing and GIS for mapping.
Worked example
A dam is proposed on limestone with karst cavities. Reasoning: karst is soluble, permeable and leaks; grouting may help but a site on impermeable granite is preferred. Answer: reject or treat the limestone site.
Traps
Porosity and permeability are not the same; clay is porous but impermeable. A confined aquifer is not the same as an unconfined one. Seismic zones in India run II to V, not I to V.