SEISMIC WAVES

WHAT ARE SEISMIC WAVES?

Before we try to explore about seismic waves and its use in geology we should know that what does seismic means. So here is the thing that word seismic is originated from Greek word “seiein” which means “to shake”. Now when we study seismic waves it is the shaking caused by waves that helps us study the detail of Earth’s Interior.

The point from where the seismic waves are originated; i.e. the seismic waves can be produced by earthquake, explosion or volcanic eruptions that cause shaking of earth; it is called as the focus.

TYPES OF SEISMIC WAVES:

There are two types of seismic waves originated:

@  BODY WAVES

@  SURFACE WAVES

WHAT ARE SEISMIC WAVES?

Before we try to explore about seismic waves and its use in geology we should know that what does seismic means. So here is the thing that word seismic is originated from Greek word “seiein” which means “to shake”. Now when we study seismic waves it is the shaking caused by waves that helps us study the detail of Earth’s Interior. Now a day’s not just the Earth’s interior but also a lot of Earth’s information is explored by the use of these waves.

The point from where the seismic waves are originated; i.e. the seismic waves can be produced by earthquake, explosion or volcanic eruptions that cause shaking of earth; it is called as the focus.

TYPES OF SEISMIC WAVES:

There are two types of seismic waves originated:

@  BODY WAVES

@  SURFACE WAVES

BODY WAVES:

“Body waves are the seismic waves that travel through the Earth’s interior”

Body waves are less destructive as compared to surface waves as they are not near the earth’s

surface and moreover they are relatively fast than surface waves. However, these waves are

further categorized as:

@  P-Waves:	@  S-Waves:
The compressional or longitudinal waves	The transverse waves.
Rock particles vibrate back and forth i.e. parallel to the direction of wave propagation.	Rock particles vibrate by a shearing motion i.e.  Perpendicular to the direction of wave propagation.
These are the fast waves.	These waves are the slower waves.
P-waves travel at the speed of 4 to 7 kilometers per second.	S-waves travel at the speed of 2 to 5 kilometers per second.
Can travel through the liquids. Such as liquid asthenosphere.	S-waves are not able to travel through liquids.

SURFACE WAVES:

“Seismic waves that travel on earth’s surface.”

Surface waves are the slowest waves that are set off during earthquake. As these waves are

nearer to the earth’s surface and have very slow speed thus these waves are extremely

destructive. Surface waves are of following two types.

@  Love waves:

Love waves are just like S-waves they move the ground perpendicular to the direction of

propagation of the waves and this result in the knocking off of the buildings from their

foundations and such destructions. Love waves cannot travel through water body i.e. liquids just

like S-waves.

@  Raleigh waves:

The most destructive seismic waves that cause major damage to the buildings are Raleigh waves.

These waves are very slow and take very long to pass through the land surface. The movement

of these waves is like rolling oceans waves they cause ground to move in an elliptical path

opposite to the direction the wave passes.