STEREONET PLOTTING
FOR PLANE
(N380E,420SE è
strike, dip amount dip direction )
(128o,42oè dip direction, dip
amount)
(120o, 400SE
è strike, dip amount
dip direction); 120o = S60oE
FOR LINE
(071o,24oè trend, plunge)
How to plot a plane when strike, dip amount and dip direction is
given?
(e.g. N38oE,42oSE)
1. trace the primitive circle of stereonet
2. mark North and South pole
3. plot strike i.e. N38oE on the primitive circle.
4. rotate the tracing paper until the mark of the plotted strike comes to
north pole (if strike is given the rotate
the tracing paper to north pole(0o) or south pole(180o)
whichever is nearer).
5. after rotating the tracing paper to north pole (as north pole
is nearer to
N38oE not south pole) see
on which side dip direction is (i.e. SE in this case).
In this case SE is on the left side
so count 42o from 90o(equator), each line
represents 2o so count 21
lines.
6 without disturbing the tracing paper draw great circle
through the point
plotted (i.e. N38oE,42oSE),
north pole and south pole. This is the required
plane.
When 90o is added
to N38oE, we get 128o and the plane becomes 1200,420.
Here 128o is dip direction and 42o is dip amount.
Let’s plot this.
1. Plot/mark 1280 along the primitive circle.
2. Rotate the tracing paper until the mark comes to 900
or 270o whichever is
nearer.
3. Count 42o from the mark (the mark being on 900
or 270o) and plot a point
(say A)
4. Draw a great circle passing through north pole, south pole
and mark A. This is required plane.
Similar process for lineation only difference is that instead of
drawing great circle only point is plotted as line in 3D is a point in 2D.
PLOTTING
FRICTION ANGLE
friction angle (say 32o) circle is a
locus of all the lines having plunge 32o.
while plotting friction angle (say 32o),
16 lines are counted from the primitive circle i.e. perimenter of the stereonet
from 90 o and 270o and circle is drawn passing from two
points with center at the center of stereonet.
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