Term
|
Definition
| downhill movement of masses of bedrock, rock debris or soil, driven by the pull of gravity |
|
|
Term
|
Definition
| have been far more costly in the U.S., in terms of both lives and dollars, than all other geologic hazards combined |
|
|
Term
|
Definition
|
|
Term
|
Definition
| descending mass moves downhill as a viscous fluid |
|
|
Term
|
Definition
| descending mass remains relatively intact and descends along well0defined surfaces |
|
|
Term
|
Definition
| movement along plane parallel to motion |
|
|
Term
|
Definition
| (slump) movement along a curved surface |
|
|
Term
|
Definition
| Material free-falls or bounces down a cliff |
|
|
Term
| Factors Controlling Mass Wasting |
|
Definition
| Steep slopes, large relief, thick layers of loose rock, debris soil, presence of water, lack of vegetation,seismic activity |
|
|
Term
|
Definition
| large elevation change from top of mountains/hills to valley floor |
|
|
Term
|
Definition
| shear forces maximized by gravity |
|
|
Term
|
Definition
| occurs anytime downward pull of gravity overcomes frictional forces resisting it |
|
|
Term
|
Definition
| is the down slope pull on the rock or debris |
|
|
Term
|
Definition
| is the force acting against the shear force; once overcome movement will occur |
|
|
Term
| Factors that can overcome shear strength |
|
Definition
| decrease friction, a process that reduces the shear strength of the actual material |
|
|
Term
| Saturated soil is less viscous and more prone to failure |
|
Definition
| due to increased pore pressure; soil particles adhere to one another due to surface tension |
|
|
Term
|
Definition
| or soil creep, very slow downslope movement of soil; freeze and thaw cycles |
|
|
Term
|
Definition
| mass wasting in which motion takes place throughout the moving mass (flow) |
|
|
Term
|
Definition
| debris moves downslope, slowly or rapidly as a viscous fluid |
|
|
Term
|
Definition
| when a block of bedrock breaks free and falls or bounces down cliff |
|
|
Term
|
Definition
| an apron of fallen rock fragments |
|
|
Term
|
Definition
| the rapid sliding of a mass of bedrock along inclined surface of weakness |
|
|
Term
|
Definition
| a very rapidly moving, turbulent mass of broken up bedrock |
|
|
Term
|
Definition
| a body of running water, confined to a channel, that runs downhill under the influence of gravity |
|
|
Term
|
Definition
| upper part of stream near its source in the mountains |
|
|
Term
|
Definition
| place where a stream enters sea, lake or larger stream |
|
|
Term
|
Definition
| a long, narrow depression eroded by a stream into rock or sediment |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| flat valley floor composed of sediment deposited by the stream |
|
|
Term
|
Definition
| (and deposition) controlled by flow velocity and discharge |
|
|
Term
|
Definition
| is the distance traveled per unit time |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| is the volume of water flowing past a given point of a unit of time |
|
|
Term
|
Definition
| flow faster along the outside of bends and more slowly along the inside, depositing point bars on the insides of the meanders |
|
|
Term
|
Definition
| may form when a new, shorter channel is cut through the narrow neck of a meander (as during a flood) |
|
|
Term
|
Definition
| are created by wind blowing over the surface of the water |
|
|
Term
|
Definition
| when waves strike coastlines and transferred to the rocks and sediments on beaches |
|
|
Term
|
Definition
| waves hitting the shoreline at an angle will bend and change direction to become more nearly parallel to the shoreline |
|
|
Term
|
Definition
| refracted waves still hit the coastline at a slight angle, pushing water and sediments parallel to the coastline |
|
|
Term
|
Definition
| dynamically supplied to beaches from several sources |
|
|
Term
|
Definition
| erosional, depositional, drowned, emergent |
|
|
Term
|
Definition
| are common where bays are separated by irregular rocky headlands jutting out into the ocean |
|
|
Term
|
Definition
| typically exhibit gently sloping plains showing few effects of erosion |
|
|
Term
|
Definition
| submergent coasts, sea level has been rising |
|
|
Term
|
Definition
| have been elevated by deep-seated tectonic forces |
|
|
Term
|
Definition
| any arid region that receives less than 25 cm of precipitation per year |
|
|
Term
|
Definition
| the predominant force shaping most desert landscapes, often violent flash floods occur |
|
|
Term
| Distribution of deserts at the equator |
|
Definition
|
|
Term
|
Definition
| deserts form downwind of where moist air rises over high mountain ranges |
|
|
Term
| Two distinct landscapes in the southwest |
|
Definition
| Colorado Plateau and Basin and Range province |
|
|
Term
|
Definition
| flat-lying sedimentary rocks, plateaus, mesas, buttes |
|
|
Term
|
Definition
| narrow hill of resistant rock with a flat top and steep sides |
|
|
Term
|
Definition
| broad, flat-topped area bounded in part by cliffs |
|
|
Term
|
Definition
| broad, flat-topped hill bounded by cliffs |
|
|
Term
|
Definition
| has rugged linear, fault-bounded mountain ranges separated by flat-floored valleys |
|
|
Term
|
Definition
| wind can keep dust in suspension, but large sand grains move |
|
|
Term
|
Definition
| are mounds of loose sand piled up by the wind |
|
|
Term
|
Definition
| is a large, long-lasting mass of ice, formed on land that moves downhill under its own weight |
|
|
Term
| Glaciers are part of earth's |
|
Definition
|
|
Term
| Two types of glaciated terrains |
|
Definition
| Alpine glaciation and continental glaciation |
|
|
Term
|
Definition
| occurs in mountainous regions in the form of valley glaciers |
|
|
Term
|
Definition
| covers large land masses in Earth's polar regions in the form of ice sheets |
|
|
Term
|
Definition
| general name for unsorted, unlayered glacial sediment |
|
|
Term
|
Definition
| is a trembling or shaking of the ground caused by the sudden release of energy stored in the rocks beneath Earth's surface |
|
|
Term
| Earthquakes breaking of rocks |
|
Definition
| brittle behavior is characteristic of near surface rocks |
|
|
Term
|
Definition
| energy is released during earthquakes |
|
|
Term
|
Definition
| released from a position along a break between two rock masses |
|
|
Term
|
Definition
| shearing (transverse)body wave in which rock vibrates back and forth perpendicular to the direction of wave propagation |
|
|
Term
| Earthquake "size" measured |
|
Definition
|
|
Term
|
Definition
| a measure of the effects an earthquake produces |
|
|
Term
|
Definition
| magnitude scale is logarithmic, 1,000 times more energy |
|
|
Term
|
Definition
| plotting distances from 3 stations on a map as circles with radii equaling the distance from the quake |
|
|
Term
|
Definition
| compressional (longitudinal) body wave in which rock vibrates back and forth parallel to the direction of wave propagation |
|
|
