Asthenosphere

The shell within the earth, some tens of kilometers below the surface and of undefined thickness, which is a shell of weakness where plastic movements take place to permit ...

asthenosphere

Earth science; Geology

The weak or "soft" zone in the upper mantle just below the lithosphere , involved in plate movement and isostatic adjustments. It lies 70 to 100 km below the surface and may ...

asthenosphere

Geography; Physical geography

Layer of rock in the mantle approximately 80km deep and at a temperature of 1400°c. Rocks here become much softer and more easily deformed than in the lithosphere above.

asthenosphere

Natural environment; Earthquake

The soft and probably partly molten layer of the earth below the lithosphere. Distinguished by low seismic-wave velocities and high seismic wave attenuation .

seismic survey

Earth science; Seismology

A technique for determining the detailed structure of the rocks underlying a particular area by passing acoustic shock waves into the strata and detecting and measuring the ...

shot

Earth science; Seismology

A small explosion used to produce shock waves during a seismic survey.

jug hustler

Earth science; Seismology

A member of a seismic crew who operates the geophones.

seismic exploration

Earth science; Seismology

An exploration technique involving the use of seismic methods.

seismic observer

Earth science; Seismology

A seismic observer operates geophysical recording instruments used in seismic surveys and performs routine maintenance to ensure optimum data quality.

scarp

Earth science; Seismology

A roughly linear, cliff-like slope or face that breaks the continuity of a surface into distinct levels. Scarps are often produced by faulting, especially that which involves a ...