A trace on the ground motion record representing the component of motion
in a horizontal plane at a right angle to the seismic wave travel
direction.
a. In seismology, a wave motion in which the motion of the particles, or
the entity that vibrates, is perpendicular to the direction of progression
of the wave train. AGI
b. In geophysics, a body seismic wave advancing by shearing displacements.
AGI
c. A wave in which the direction of propagation of the wave is normal to
the displacements of the medium; e.g., a vibrating string. The gravity
wave in which fluid parcels move in circular orbits is an example of a
mixed transverse-longitudinal wave. The Rossby wave is also mixed, except
in the case of zero current speed, when it is a transverse wave.
Syn:distortional wave; secondary wave. See also:S wave
See:overhand stoping
a. Any dark-colored fine-grained nongranitic rock, such as a basalt,
peridotite, diabase, or fine-grained gabbro; also applied to any such rock
used as crushed stone. Syn:trapp; traprock; trappide. CF:whinstone
AGI
b. A device for separating suspended sediment from flowing water; e.g., a
sand trap. AGI
c. A door used for cutting off a ventilating current and that is
occasionally opened for haulage or passage. See also:trapdoor
Fay
d. A device to separate denser material from less-dense material, such as
entrained water in a stream or a compressed-air line. Long
e. That portion of any mass of porous, permeable rock that is sealed on
top and down the sides by relatively nonporous and impermeable rock and
that lies above the intersection of a horizontal plane passing through the
lowest point of complete sealing.
A gem with a row or rows of steplike facets around the table and culet (or
small lower terminus of the gem, parallel to the table), or around the
culet alone. See also:step cut
a. A door in a mine passage to regulate or direct the ventilating current.
Also called weather door. See also:trap
b. See:air door
a. An isometric crystal form of 24 faces, each face of which is ideally a
four-sided figure having no two sides parallel, or a trapezium.
Syn:leucitohedron
b. A crystal form consisting of six, eight, or twelve faces, half of which
above are offset from the other half below. Each face is, ideally, a
trapezium. The tetragonal and hexagonal forms may be right- or
left-handed. AGI
A quadrilateral that has only two sides parallel. Jones, 2
A rule for estimating the area of an irregular figure by dividing it into
parallel strips of equal width, each strip being a trapezium.
See also:Simpson's rule
See:trap
a. An employee, normally an apprentice, used to open and close mine doors.
Also called trapper boy; nipper; door tender; doorman. Syn:door boy
BCI; Fay
b. An employee who assists the dispatcher by throwing switches and
attending telephone at an inside station. BCI
See:trapper
See:trap
Points placed on a railway line to derail a train that has been
incorrectly signaled. Hammond
See:trap
Protective screen for removing detritus from the pulp stream ahead of a
processing unit. Pryor, 4
A common name in the older literature for unwelded massive ash and
pumice-flow deposits. Trass has been used in the production of pozzolan
cement. CF:ignimbrite
The angle of draw advancing with a moving face. Nelson
See:apron