Geophysical Info—type And Characteristics Of Faults

- Jul 19, 2019-

Compressive fault

1. The fracture surface is often soothing and wavy, especially in the direction of the strike.

2. There are often many scratches, steps, and polished surfaces on the fracture surface. Newly-developed flakes (such as mica, talc, chlorite) and crushed or elongated columnar minerals, flaky minerals, gravel, granules, quartz, calcite wafers and ingots The fracture surface and the two sides are arranged close to the parallel fracture surface

3. The tectonic rocks in the fault are mainly breccia, mylonite, fault mud, and sometimes the structural lens is also visible.

4. The rock on both sides of the fracture surface is broken, pulled and broken due to strong extrusion, resulting in some associated structures, such as plume-like fissures, cleavage, "in" shape structure (including faults and folds), small revolving Structure, etc.

5. The fracture surfaces often appear in groups, parallel to each other, extend farther along the strike, and often form a tiling pattern on the profile.

6. Reverse fault (including thrust fault, reverse fault fault 辗 blanket) is a compressive fault

Tensile fault

1, the fracture surface is rough and irregular, and the shape is irregular. Less scratches, less frequent scratches, and generally steeper dip

2. When the tensile fracture occurs in the conglomerate, the fracture surface often passes through the gravel without cutting or flattening.

3. There is no obvious change in the occurrence of rock formations on both sides of the fracture surface.

4. The tectonic rocks are mainly breccia, and the mylonite and fault mud are rare. The breccia is very large in size and has no significant orientation

5, tensile breaks are often distributed in groups, forming a tensile fault zone. They are parallel to each other on a plane, and often form a basement, a step, and the like on the cross section. Any tensile fracture that tracks the "X" shape fracture is jagged, called "Zigzag" fracture.

6, normal fault is a tensile

Torsional fault

1. The fracture surface is often smooth, flat, and sometimes mirror-like, often with a large number of horizontal or near-level scratch steps. The fault is stable and the fault line is straight.

2. There are sometimes new metamorphic minerals such as siliceous, calcite and chlorite on the fracture surface, but not as common as the compressive structural surface.

3. The tectonite is often milled very fine, with breccia and mylonite, and has a narrow strip of physicochemical properties. Tectonic rock often formed in oblique distribution and torsional fault zone

4. On both sides of the fracture surface, the rock is often accompanied by some pinnate cracks and cleavage due to strong twisting, "in" shape and small convolution structure.

5. Twisted fractures often appear in groups, two groups are parallel, and have an "X" shape (often cut into diamonds), sometimes in a geese line

6 translational fault is a torsional fault

Compression tomography

1. That is, it has a compressive characteristic and has a torsional characteristic. The characteristics of the above-mentioned compressive and torsional fractures can be used for reference.

2. Scratches and steps showing the oblique slanting of the upper plate are often seen on the fracture surface. Some associated structures may occur in the two plates of rock, such as traction, pinnate fissures, cleavage, "in" branching and spiral construction. The intersection of the axial plane, the fracture surface and the main fracture surface of these associated structures is not parallel to the strike line of the main fracture surface, nor parallel to the trend line, but between the two, which is the compression A characteristic of sexual fracture

3 compression and torsion fractures often appear in groups, forming geese in a row and flat form

4 translational reverse fault and reverse translation fault are all compression torsion faults