Geologic hazards
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A Geologic Hazard is one of several types of adverse geologic conditions capable of causing damage or loss of property and life. These hazards can consist of active fault (fault exhibiting recent movement or seismic activity), fault rupture (displacement of the ground along a fault), landslide (lateral displacement of earth materials on a slope or hillside), rock falls (tumbling down of rock masses), rock slides, debris flows, mudflows (landslides consisting of soft and wet earth materials), avalanches, volcanic eruptions, ash falls, thermal springs, earthquakes, liquefaction (settlement of the ground in areas underlain by loose saturated fine sand and silt during an earthquake event), seismically induced settlement, settlement (ground settlement due to consolidation of compressible soils or due to collapseable soils), ground subsidence, sea caves, sinkholes, voids, erosion, heave, displacement, collapse, burial or inundation, or other conditions due to geologic, seismic, tectonic forces and movements. Sometime the hazard is instigated by man on by the careless location of developments or construction in which the conditions were not taken into account.
Geologic Hazard Evaluation
Geologic hazards are evaluated by an engineering geologist educated, trained and experienced in engineering geology for their recogition, investigation and analysis. Often in conjunction with a geotechnical engineer, the engineering geologist is qualified to formulate recommendations for the mitigation of the hazards. Mitigation can include avoidance of the hazards or relocation; construction of slope stabilization measures (earth buttress, retaining walls, diversion walls, shear pins, tiebacks, soil nails or soil anchors, revetments, injection of grout or concrete, deep foundations, tunnels, subdrains), and other measures.