Glossary - The Solid Earth - page 655

band-pass filter filters a signal to retain only those frequencies within the required range,
e.g., 5-40 Hz.

basalt mafic igneous rock.

basement rock continental crust that provides the substrate for later deposition.

basin depression in which sediments collect.

batholith large body of igneous rock, several kilometres thick and extending over areas up to
thousands of square kilometres.

bathymetry depth of the seabed.

beta decay radioactive decay by emission of an electron.

beta particle electron. An elementary particle with a charge of − 1.

blueschist low-grade metamorphic rock; formed at lower temperatures and higher pressures
than greenschist; characterized by blue minerals.

body wave seismic wave that travels through the interior of the Earth; P-waves are
longitudinal body waves; S-waves are transverse body waves. Body waves are short-period
( ∼ 0.1-20 Hz), short-wavelength ( < 100 km) waves for which ray-theory approximations are

valid.

body-wave magnitude magnitude of an earthquake as estimated from the amplitude of body
waves.

bulk modulus ( K ) bulk property of a material; equal to the pressure acting on a sample
divided by the resultant fractional decrease in volume of that sample.

cation positively charged ion.

centripetal acceleration acceleration of a body with a circular motion, towards the
centre of that circle; proportional to the square of the body's velocity and inversely
proportional to the radius of the circle; depending on one's point of view, also called
centrifugal acceleration.

CHUR chondritic uniform reservoir (see Section 6.8 ).

compensation depth depth at which the overlying rocks are assumed to exert a constant
pressure; below this depth, there are no large lateral variations in density.

compressional waves another name for P-waves. See body waves.

conduction transfer of heat by molecular collisions.

continental rise part of the continental margin between the continental slope and the abyssal
plain; slopes generally 1 : 40 to 1 : 2000.

continental shelf part of the continental margin between the coast and the continental slope;
slopes about 0.1 ◦ (1 : 500).

continental slope part of the continental margin between the continental rise and the
continental shelf; slopes about 3-6 ◦ (1 : 10 to 1 : 20).