Magneto-Telluric Survey in the Delhi-NCR Region

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Magnetotelluric Study

Mains level : Earthquakes

In the backdrop of multiple quakes of low intensity in the Delhi-NCR region, the National Centre for Seismology (NCS) is conducting a unique geophysical Magnetotelluric-MT survey to accurately assess potential seismic hazards.

Try this PYQ:

Q.Consider the following statements:

  1. The Earth’s magnetic field has reversed every few hundred thousand years.
  2. When the Earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide.
  3. When living organisms originated, they modified the early atmosphere of the Earth.

Which of the statements given above is/ are correct?

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

What is Magneto-Telluric Survey?

  • MT is a geophysical method which uses natural time variation of the earth’s magnetic and electric fields to understand the geological (underground) structure and processes.
  • It is an increasingly popular technique widely used to image the electrical resistivity distribution inside the Earth in various application fields ranging in scale from the shallow crust to the lithosphere.
  • In the MT method, the earth’s natural electromagnetic field is used as a source field.
  • The receivers record the electric and magnetic fields on the surface of the Earth.
  • The variations in amplitude and phase of the received signals can be interpreted in terms of the resistivity structure of the subsurface using the magnetotelluric impedance.

Where would the MT survey be undertaken?

  • The survey is conducted across three major seismic sources, namely Mahendragarh-Dehradun Fault (MDF), Sohna Fault (SF) and Mathura Fault (MF).
  • It will ascertain the presence of fluids, which generally enhance the possibility of triggering earthquakes.

Benefits of the survey

  • Its findings will help different user agencies for designing quake-resistant buildings, industrial units and structures such as hospitals and schools.
  • In addition to MT, analysis and interpretation of satellite imageries and geological field investigations for locating the faults are also being carried out.
  • Both these geophysical and geological surveys will help in taking multiple preventive measures in the quake-prone region.
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