The deadliest and strongest earthquakes in recorded history

Subject :Geography

Section: Physical geography

Deadliest and strongest earthquake in the world:

A powerful earthquake of magnitude 6.8 struck Morocco capital Marrakech recently.
Significant earthquake events database is maintained by the National Centres for Environmental Information (NCEI) in the USA.
The deadliest earthquake in terms of magnitude came in 1960 in Puerto Montt, Chile with a magnitude of 9.5.
The deadliest earthquake in terms of death and damage came in Shaanxi, China in 1556, causing a death toll of 8.3 lakh.

India:

The Bhuj earthquake (7.6 magnitude) was the deadliest earthquake in India with a death toll of more than 20000 people.
In terms of magnitude, the strongest earthquake in India came in Andaman and Nicobar Islands in 1941 and 1897 Assam earthquake. Both were of magnitude 8.

Other major earthquakes in India:

Seismic waves:

Seismic waves are the vibrations from earthquakes that travel through the Earth and are recorded on instruments called seismographs.
Seismographs record a zigzag trace that shows the varying amplitude of ground oscillations beneath the instrument.

Measurement of earthquake:

Two scales are used widely to measure the earthquake:
- The Mercalli scale bases its measurement on the observed effects of the earthquake and describes its intensity. It is a linear measurement. It measures the intensity of earthquake on a scale of 1-12.
- The Richter scale measures the seismic waves, or the energy released, causing the earthquake and describes the quake’s magnitude. It is logarithmic. It measures earthquake magnitude in a scale of 0-10.