M6.1 Earthquake in the Nicobar Islands, India region — August 3, 2021
2021-08-03 03:42:38 UTC (2021-08-03) · approx. 9:42 AM UTC+6 local
Felt by 9 people across nearby locations. Maximum shaking intensity MMI 4.1 (moderate).
On August 3, 2021 at 03:42 UTC, a magnitude 6.1 shallow crustal earthquake struck in the Nicobar Islands, India region, at a depth of 10.0 km and coordinates 8.8809°, 94.0192°. The earthquake was reported felt by 9 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 4.1 (moderate). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.
Physical scale: An earthquake of magnitude 6.1 releases seismic energy equivalent to roughly 21 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 9.7 km — a useful intuition for the size of the slip patch on the fault.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 9 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 33,105 |
| MMI 4 | light | 28,184 |
Earthquake Details
94.0192°E
Technical Information
Common Questions
How strong was the magnitude 6.1 earthquake in the Nicobar Islands, India region?
The magnitude 6.1 earthquake that struck in the Nicobar Islands, India region on August 3, 2021 at 03:42 UTC had a depth of 10.0 km. It was felt by 9 people with maximum shaking intensity of MMI 4.1 (moderate). For context, this was a strong earthquake capable of causing significant damage.
Where did the earthquake occur?
The earthquake epicenter was located at 8.8809°, 94.0192°, which is in the Nicobar Islands, India region.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 6.1 earthquakes can continue for weeks to months and gradually diminish over time.
Actions
Location
Authoritative source: USGS event page (event ID: us6000f1r4). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, August 3, 2021). M6.1 Earthquake in the Nicobar Islands, India region — August 3, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000f1r4/