It is a device used to record and detect earthquake. It basically works by detecting or responding to ground motion or vibration. Vibration caused by earthquakes, volcanic eruptions, explosions etc .
Seismograph also called as Seismometer is used to detect seismic waves. Seismic waves means an elastic wave in the earth produced by an earthquake or other means.
It basically consists of 2 parts
- Timing device
- Recording device
Basic principle of seismograph is as shown in image below
What is Seismology
The scientific study of earthquakes and internal structure of the Earth. It also includes the study of the origin, geographic distribution, effects, and possible prediction of earthquakes.
What are Seismic waves and what are its types?
Seismic waves means an elastic wave in the earth produced by an earthquake or other means.
Types of seismic waves
Primary waves – P waves
- They are longitudinal in nature
- They are pressure waves hence travel faster than other waves
- It can traverse through solids, liquids and gases as well.
Secondary waves – S waves
- They are traverse in nature
- They arrive after P waves
- It can traverse only through solids
How the waves work is nicely shown in the video in this link – https://www.britannica.com/video/181934/rock-vibrations-Earth-earthquake-waves-P-surface