Explanation:

Earthquake swarm is a series of many (sometimes thousands) low magnitude earthquakes without a discernible main shock. They occur in a localised region and over a period of time ranging from days, weeks to even months, without a clear sequence of foreshocks, main quakes and aftershocks.

When seismic energy piles up inside the Earth and is released in small amounts from certain points, such a series of earthquakes can occur. Sometimes, these are also accompanied by acoustic or sound emissions.

• Dahanu    town    in    Maharashtra’s    Palghar district has been hit by some 30 low-intensity earthquakes since November 2018.
• Palghar was rocked by a series of minor earthquakes (6 tremors) on a single day recently.
• The magnitudes of the quakes ranged between 3 and 4.1 on the Richter scale.
• Many aftershocks of lesser magnitude have also been observed in the area.
• Data collected so far point to an “earthquake swarm”.