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Maharashtra recorded 29 small earthquakes between 30 July and 14 August 2026 - 24 in and around Nashik, four in Palghar and one in Nagpur.
Magnitudes ranged from 2.0 to 4.3 at depths of roughly 5-8 km; the largest was a magnitude 4.3 event at Nashik on 8 August at a depth of 5 km.
Seismologists classify the sequence as an earthquake swarm - many events of comparable size in a small area with no identifiable main shock.
Monsoon water percolating into cracks in Deccan basalt builds pore pressure that is released as shallow tremors; Maharashtra saw comparable episodes in September 2023 and February 2019.
Nashik and Palghar fall in Seismic Zone III under IS 1893, and the shallow depth makes it unlikely that the swarm will be felt in Mumbai.
In an ordinary sequence there is one clearly largest event - the main shock - followed by aftershocks that decay in size and frequency. A swarm has no such hierarchy: many events of broadly comparable magnitude strike a small area over days or weeks, sometimes running into the thousands, without any one of them standing out as the main shock. Because stored strain is being let out in small instalments from several points rather than in one large rupture, the individual events are usually low in magnitude. The distinction matters for public communication: the absence of a main shock is a description of what has happened so far, not a guarantee about what will follow.
Simple Analogy: A main shock with aftershocks is a dam bursting and then dripping. A swarm is a hundred small leaks opening across the same wall, none of them the burst.
Koynanagar earthquake, magnitude 6.3 - the classic Indian case of reservoir-triggered seismicity, near the Koyna dam in Maharashtra
Latur (Killari) earthquake, magnitude 6.2, in a part of peninsular India long regarded as stable
Earlier earthquake swarm episode in Maharashtra
Most recent previous swarm episode in the state
Current sequence begins
Largest event of the sequence - magnitude 4.3 at Nashik, depth 5 km
Count reaches 29 events over 16 days
Nodal agency of the Government of India for monitoring earthquake activity, operating the national seismological network and issuing earthquake parameters
Administrative ministry for seismology, meteorology, ocean science and polar research
Apex body for disaster management policy and guidelines under the Disaster Management Act, 2005
GS Paper I > Geography > Geophysical phenomena such as earthquakes; GS Paper III > Disaster and disaster management
General Awareness > Geography > Earthquakes and seismic zones of India
A sequence of many earthquakes of comparable magnitude in a small area over a short period, with no identifiable main shock.
The depth below the surface at which the rupture originates; shallow events shake a smaller area but more intensely near the epicentre.
Movement of centimetres to tens of centimetres along a fault spread over weeks to years - an earthquake in slow motion, releasing energy without strong shaking.
Earthquakes induced by the impounding of water behind a large dam, which alters stress and pore pressure in the underlying rock; Koyna, 1967, is the classic Indian case.
Continental interior far from plate boundaries, with low but not zero earthquake frequency - and occasionally damaging events, as at Latur in 1993.