Foundation, Concrete and Earthquake Engineering

What is Fault Move ment? what is Dipslip Movement?

Dear reader we have already discussed about movement of fault in our previous post. Here actually we will define type of fault movement. Fault movement can geologically reduced to two components i.e. in strike and dip direction. The movements are:

a. Dip slip movement

b. Strike slip movement

But some movements have components in both directions; however only one direction of movement is generally predominant.

In this post We will discuss about dip-slip fault movement. From the term dip-slip movement, we can easily realize that movement is primarily occurred along dip direction or can be said normal to strike. Different types of dip-slip movement also found depending on dip angle and direction of movement of respective fault. They are:

a. Normal faults

b.Reverse fault

c.Thrust faults

a. Normal faults:

These types of movement are happened when dip-slip movement have horizontal component of extensional type. in this regard we are introducing two term

Normal faulting during earthquake-Hang wall

-Foot wall

Hang wall:

The materials remain above inclined fault plane is called hang wall as shown in figure below:

Foot wall:

The materials beneath fault plane is called foot wall as shown in figure above.

So when hang wall moves down ward with respect to foot wall, normal fault movement is occurred which is usually observed in conjunction with tensile stress within the earth crust producing lengthening of crust in horizontal direction.

Reverse faulting during earthquakeb.Reverse faulting:

When the movement have compressional horizontal movement, reverse faults are said to be occurred. In this movement hang wall move upward with respect to foot wall and horizontal shortening (crust) is observed.

c. Thrust faulting:

In this movement also hang wall move upward with respect to foot wall but difference is small angle of dip of fault plane. The example is European Alps which is thrust structure indicating potential of producing large movement.

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