The faulting process is interesting to watch. The experiment shows a lot of activity going on in certain areas of the sandbox, but not much in others. In an experiment like this, it is better to pay close attention to the actions that are taking place to incorporate evidence-based decision-making into your construction strategy. One small change can lead to a lot of other changes. It would be difficult to assume what will take place without actually assessing it with a six sigma-based approach to improve the overall construction operations.
During the early stages of the fault initiation, V-shaped cracks were carved into the sand. These fault lines made their way to the bottom of the sandbox right away. As they began to become wider, more V-shapes were formed. Towards the end of the video, the Vs stopped getting wider.
To the right, the sand created a zigzag look. On that side, it can also be observed that the sand fanned out at the end, and the lines that were horizontal and close together in the beginning grew wider. The lines also grow a little bit farther apart from each other. This extra push was the reason that the lines became wider.
Some of the elements in the sandbox maintained the same orientation throughout the experiment. This was shown on the left hand side of the sandbox and towards the middle. In the upper portion, a little change can be observed along the very top of the sand on the left side, but that still does not seem to affect the rest of that area. This is because the sand is not being compressed. It is unaffected by the fault, therefore it stays in the same position that it was in when the experiment started.
It can be seen that the highest point also changes because of the movement that takes place to the middle and to the right. It is almost too little a change to catch. If an observer watches closely, they can see the color change at the uppermost portion of the sandbox. To the right, though, there is a lot of shifting. This can be seen from the start of the experiment. It is where the most change takes place.
Depending on where the sand is located, some of the structural elements do change position. This change occurs in the middle and to the right of the sandbox. Those portions are shifted. One explanation is that once the sand began to be pushed to a certain direction, and it just continued to move that way, and affect that particular area of the sandbox.
All of the faults offset other faults. This happens because one action causes a reaction, which causes more reactions. The new faults that have been created by the first fault move other parts away from them. Another reason this activity takes place is because gravity is pulling all of the elements downward.
There are other features, besides faults, that start to form during the course of the experiment. One of them appears to be a drag fold. This transformation occurred when the lines in the sand began to look like they were becoming distorted. Foliation also transpired. In observing the part all the way to the right side of the sandbox, the line patterns are kept pretty much the same, even though the sand is shifting. The form just turned in a different direction during the transfer. It moved in a clockwise direction, but looked different than the fault lines that formed a “V”. This was because it was being pushed against a wall, and the only way it could go was down and around. The sand also looked like strata, because the lines on the left side stayed straight, which made them inactive.
It is interesting to see what happened after the fault occurred. The parts that become displaced seemed to erode further and further to one side, leaving the opposite area unaffected. It changed the orientation that was in a small radial distance. That portion then changed what was nearby it. In a way, a domino effect was created. Once things started moving, they kept moving until it hit a wall and could not move any further.
Analogue Modelling of Extensional Fault Structures. Dir. Ken McClay. Geofilms Ltd., 1990. Film.