- An 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 disciplines.
- NCS 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.
- Hydro-seismicity 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
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