earthquake of magnitude 4.3 has Palghar in northern Maharashtra. An earthquake
is the result of a sudden release of stored energy in the Earth’s crust that
creates seismic waves. The magnitude is a number that characterizes the
relative size of an earthquake. Earthquakes are measured with a seismometer,
commonly known as a seismograph.
Palghar district has been witnessing an unusual
frequency of earthquakes since November, 2018. This had led to the
establishment of three temporary field stations of the National Centre for
Seismology (NCS) to observe and record the seismic activity. National Centre
for Seismology, Ministry of Earth Sciences is nodal agency of Government of
India dealing with various activities in the field of seismology and allied
has categorised the unusual tremors in Palghar as an ‘earthquake swarm’. Earthquake
swarm is a series of low magnitude earthquakes that occur in a localised region
and over a period of time ranging from days, weeks to even months.
is hypothesised as the reason for swarms in peninsular India. In this case, water
from heavy rainfall enters small fractures in rocks. This
raises the pressure within them. This pressure is released in earthquake swarms.
According to experts, such activity typically starts in June and dies down in
December; however in Palghar this has continued. This has raised questions
about the mechanism behind it