2. (Geol. & Mining) A dislocation caused by a slipping of
rock masses along a plane of facture; also, the dislocated
structure resulting from such slipping.
Note: The surface along which the dislocated masses have
moved is called the
{fault plane}. When this plane is vertical, the fault is a
{vertical fault}; when its inclination is such that the
present relative position of the two masses could have
been produced by the sliding down, along the fault plane,
of the mass on its upper side, the fault is a
{normal}, or {gravity}, {fault}. When the fault plane is so
inclined that the mass on its upper side has moved up
relatively, the fault is then called a
{reverse} (or {reversed}), {thrust}, or {overthrust},
{fault}. If no vertical displacement has resulted, the fault
is then called a
{horizontal fault}. The linear extent of the dislocation
measured on the fault plane and in the direction of
movement is the
{displacement}; the vertical displacement is the
{throw}; the horizontal displacement is the
{heave}. The direction of the line of intersection of the
fault plane with a horizontal plane is the
{trend} of the fault. A fault is a
{strike fault} when its trend coincides approximately with
the strike of associated strata (i.e., the line of
intersection of the plane of the strata with a horizontal
plane); it is a
{dip fault} when its trend is at right angles to the strike;
an
{oblique fault} when its trend is oblique to the strike.
Oblique faults and dip faults are sometimes called
{cross faults}. A series of closely associated parallel
faults are sometimes called
2. Sobriety of character or demeanor. ``Men of gravity and
learning.'' --Shak.