What is the Difference Between Reverse Fault and Thrust Fault

The main difference between reverse fault and thrust fault is that in reverse fault one side of the land moves upward while other side remains still whereas thrust fault is a break in the Earth’s crust across which older rocks are pushed above young ones.

A fault in geology refers to a planar fracture or discontinuity which occurs as a result of rock-mass movement. Plate tectonic movements cause large fractures. E.g. transform faults. The release of energy that is associated with a fault is called an earthquake. There are different types of geological faults such as strike-slip fault, dip-slip fault, etc. We can mainly categorize them as normal fault, reverse fault, and thrust fault.

Key Areas Covered

1. What is Reverse Fault 
     – Definition, Characteristics, Formation
2. What is Thrust Fault
     – Definition, Characteristics, Formation
3. What is the Difference Between Reverse Fault and Thrust Fault
     – Comparison of Key Differences

Key Terms

Fault, Reverse Fault, Thrust Fault

What is Reverse Fault

A reverse fault is a type of dip-slip fault where one side of the land moves upwards while the other side stays still. The non-moving land is called the footwall while the side that moves is called the hanging wall. Therefore, it is the opposite of a normal fault. This type of faults causes the compressive shortening of the crust. When compared to a normal fault, the dip of this type of fault is very steep (about 45 degrees). However, this type of faults is less common than normal faults.

Figure 1: Reverse Fault

Compressional stresses can cause a reverse fault. Here, the hanging wall and the footwall are pushed towards each other, causing a compression. In contrast, normal fault is caused by tensional stresses, which cause the hanging wall and footwall to be pulled apart from each other.

What is Thrust Fault

Thrust fault is a break in the Earth’s crust where older rocks are pushed above younger rocks. It is a type of reverse fault because in both cases – one side of the land moves upwards while the other side remains still. There are some different forms of thrust faults such as blind thrust faults, fault-bend folds, fault-propagation folds, and thrust duplex.

Figure 2: Thrust Fault

A blind thrust fault refers to an instance where the fault plane terminates before it reaches the ground level. These faults are difficult to be captured since they mostly lie underground. When a thrust fault is involved with a thin-skinned style of deformation, it is called a fault-bend fold. A fault-propagation fold occurs at the tip of a thrust fault where we can observe that the fault is continuing after some time. Thrust duplexes occur when there are two decollement levels close to each other within a sedimentary sequence.

Difference Between Reverse Fault and Thrust Fault

Definition

A reverse fault is a type of dip-slip fault where one side of the land moves upwards while the other side stays still in contrast, a thrust fault is a break in the Earth’s crust where older rocks are pushed above younger rocks.

Occurrence

In a reverse fault, one side of the land moves upwards compared to the other side of the land, whereas in a thrust fault, older rocks get pushed above younger rocks.

Conclusion

A fault is a planar fracture or discontinuity which occurs as a result of rock-mass movement. The main difference between reverse fault and thrust fault is that in the reverse fault one side of the land moves upward while other side remains still whereas thrust fault is a break in the Earth’s crust where older rocks are pushed above younger rocks.

Reference:

1. “Fault (Geology).” Wikipedia, Wikimedia Foundation, 21 May 2020, Commons Wikimedia.
2. “What Is Reverse Fault.” Study.com, Available here.
3. “Thrust Fault.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.

Image Courtesy:

1. “Fault-propagation fold” By Ross S. Stein and Robert S. Yeats – Hidden Earthquakes – (Public Domain) via Commons Wikimedia
2. “Mountain by reverse fault” By takami torao (Koiroha (talk) 14:19, 29 August 2009 (UTC)) – Own work (Public Domain) via Commons Wikimedia