Pressure Release Study, Part II
by Tom Brown, Jr.
In the last issue, we concerned ourselves with a study of the major pressure releases
of changing forward motion and foot mapping. In this issue, we will concentrate on
pressures against the wall (see Figure 1), which tell how much pressure is exerted on any
side, front, or rear of a track. The wall is that part of the track which is formed when
the print is placed in the ground, extending from the ground level to the bottom of the
Understanding the wall pressure release systems will help you determine how much
pressure is placed on the wall, thereby indicating turning, pivoting, sliding, and so many
other nuances that are found in each individual track. Keep in mind that I am only
covering the major pressure releases and many points are left out in between. These points
will become evident when you have put in a few thousand hours of dirt time and are looking
for much finer detail. Also, keep in mind, no matter what the soil, these same pressure
releases occur in the same order. Of course, on hard dirt you will need a magnifying glass
to read the dirt particles that will lay in the ways to be mentioned.
|Cliff (see figure 2)
Any time a print goes straight in and out, a wall, or cliff will occur. This indicates
that there is no pressure against the wall. The cliff is usually at a 90 degree angle from
the ground level to the bottom of the track.
Ridge (see figure 3)
As pressure is placed against the wall, a small ridge is formed at the ground level that
will continue along the outside of the track until the point where the pressure stops. The
greatest point of pressure on ridges are marked by peaks. These peaks are very important
in determine indicator pressure releases and the exact points of pressure determine subtle
changes in movement.
Crest (see figure 4)
As the pressure increases against the wall, the ridge is built higher and the dirt
begins to crest backwards over the foot.
Remember that this pressure release will still stay intact when the foot is removed
-because the foot restricts and is pulled out evenly. Any more pressure beyond a crest
will result in what is known as a cave or caving (see Figure 5), then continuing on to a
cave-in (See Figure 6). Keep in mind that weathering will crumble a crest and it could be
misread by an inexperienced tracker.
|Plate (see figure 7)
With extreme pressure now against the wall, a huge plate is thrown up. The whole wall
rides up and above the ground level resulting in a plating effect. A number of these
plates can occur at the same time, the largest ones being the area of greatest pressure.
Plate Fissure (see figure 8)
Even more pressure now causes the plate to throw long cracks called fissures. Keep in
mind, any time the term "crack" is used alone it means that the dirt has cracked
or broken due to weath ring and not to stress; fissures refer toe stress. If the pressure
continues, then the plate crumbles, showing even greater pressure and stress against the
wall (See, Figure 9).
|Explosion (See Figure 10)
An explosion is the greatest amount of pressure and stress any wall can stand and
usually means that the wall is completely blown out. This usually takes a very violent
motion, and the stress can be judged by the amount of dirt kicked out of the track and the
distance it has traveled.
Practicing Pressure Releases
All dirt moves in the same way with few exceptions, but all types
have their own quirks, depending on consistency, moisture, and composition. Fortunately,
these will not affect the major pressure releases listed, but only those minute ones that
take much time and study to learn. By the time you get to that point, you know most dirt
very well and are aware of the little inconsistencies of the soil you are working with.
To practice pressure releases, it is best to find a damp, sandy beach; being an ocean,
lake, or stream will make little difference. Usually, these areas are littered with tracks
of men and animals, but it is a good idea to wipe the slate clean and make your own.
Practice the various speed variations and changes you learned in the last newsletter, then
various turns and pivots. Pick out the pressure releases you see in the illustrations.
This way when you make the track you know exactly what you were doing, how fast you were
going, and to what degree you turned.
Later, as your skill increases, go for the other human tracks you find, then to the
animals. Don't graduate to different dirt until you can master the releases in simple sand
situations. Then, slowly bring your skill up by trying more and more difficult dirt until
you can see the pressure releases in hard-packed earth in the form of dust particle
As you get more advanced, you will discover how each digit and portion of a finger or
toe can have its own set of pressure releases differing from others on the same foot. This
and other advanced methods will be covered in future articles along with some of the more
isolated releases and pivots common to all tracks.
Many of you have written to me about the foot mapping portion of the last article and
how you thought it could be done better. You are right, providing that is all there is to
pressure releases. But, unfortunately, there is so much more, and only that system will
work for the more advanced methods and especially correlate to the depth foot mapping that
we will discuss in later issues. So please use this method. You'll soon see why it is the
only way that will work.
Some people have asked how it would be
possible to map a small foot such as a rodent's forepaw. Simply draw to scale, saying that
one inch equals one foot, then draw in the pressure releases on the foot map. A magnifying
glass is helpful in reading mice and other small animal pressure releases.
From The Tracker magazine,
published by the Tracker School.
For more articles from The Tracker magazine, visit the
Tracker Trail website.