LAB EXAM Flashcards
what is strike
the orientation of a level line on an inclined surface
what is azimuth
the horizontal angle between a line and north, measured clockwise, and is always written with three digits
what is quadrant
the angle between a line and a specified coordinate direction, usually true north or south
what is dip
the inclination (vertical angle) of the greatest slope of an inclined plane, measure perpendicular to strike, and must always include a dip direction
what is written strike or dip
strike
what is plunge
the inclination between horizontal and the linear feature
what is trend
the orientation of a horizontal line parallel to the linear feature and pointing in the down plunge direction (must have three digits)
planes that dip upstream, “V”…
“v” points upstream
planes that dip downstream at the same angle as the stream gradient, the “v”…
will not exist
planes that dip downstream at an angle shallower than the stream gradient, the “v”…
“v” point upstream
planes that dip downstream at an angle greater than the stream gradient , the “v”…
“v” points downstream
vertical planes go straight across all topography
no “v”
horizontal planes follow contour lines and will…
follow the “v” for the stream
what is a great circle
the intersection of the equator in two diametrically opposed points
what is a spherical projection
a projection onto the equatorial plane of the lower half of the sphere
what is a stereonet
the grid defined by the stereographic projection of great and small circles
equal angle projection
the angle between the two tangents to great circles on the net
what is a beta diagram
great circle plots of the limb planes, with their intersection being the fold axis
how to find fold axis of beta diagram in stereonet
plot limbs as planes then calculate the plane intersection
what is a Pi diagram
the fold axis is found by aligning the limb plane poles onto a great circle, and finding the pole to that circle
how to find fold axis from Pi diagram in stereonet
find the poles of the planes and click on stereonet for intersection
