Help Ukraine

Light mag. 3.9 earthquake - Bering Sea, 51 mi southwest of Atka, Aleutians West, Alaska, USA, on 18 Jul 11:30 am (GMT -9) -

Light mag. 3.9 earthquake - Bering Sea, 51 mi southwest of Atka, Aleutians West, Alaska, USA, on 18 Jul 11:30 am (GMT -9) Light mag. 3.9 earthquake - Bering Sea, 51 mi southwest of Atka, Aleutians West, Alaska, USA, on 18 Jul 11:30 am (GMT -9)

Light magnitude 3.9 earthquake at 49 km depth

18 Jul 20:58 UTC: First to report: EMSC after 28 minutes.
18 Jul 20:58: Now using data updates from USGS
18 Jul 21:02: Magnitude recalculated from 3.5 to 3.9. Hypocenter depth recalculated from 25.9 to 48.9 km (from 16.1 to 30 mi). Epicenter location corrected by 22 km (14 mi) towards NNW.
Update Sun, 18 Jul 2021, 21:06
Small magnitude 3.9 earthquake 51 miles southwest of Atka, Alaska, United States
3.9 quake 18 Jul 11:30 am (GMT -9)
3.9 quake 18 Jul 11:30 am (GMT -9)
Just 36 minutes ago, a 3.9-magnitude earthquake struck near Atka, Aleutians West, Alaska, USA. The tremor was recorded in the morning on Sunday 18 July 2021 at 11:30 am local time, at a moderately shallow depth of 30 miles below the surface.
The event was filed by the United States Geological Survey, the first seismological agency to report it.
Our monitoring service identified a second report from the European-Mediterranean Seismological Centre (EMSC) which listed the quake at magnitude 3.9 as well.
According to preliminary calculations, we do not expect that the quake was felt by many people and did not cause any damage. In Atka (pop. 64, 51 miles away), the quake was probably not felt.

Download the Volcanoes & Earthquakes app and get one of the fastest seismic alerts online:
Android | iOS

Earthquake data

Earthquake details

Date & timeJul 18, 2021 20:30:13 UTC -
Local time at epicenter18 Jul 11:30 am (GMT -9)
Depth48.9 km
Epicenter latitude / longitude51.7744°N / 175.1854°W (Bering Sea, Alaska, United States)
Antipode51.774°S / 4.815°E
Shaking intensityWeak shaking near epicenter
Felt0 reports
Primary data sourceUSGS (United States Geological Survey)
Nearest volcanoKasatochi (49 km / 30 mi)
Nearby towns and cities82 km (51 mi) SW of Atka (pop: 64) | Show on map | Quakes nearby
100 km (62 mi) E of Adak (pop: 332) | Show on map | Quakes nearby
Weather at epicenter at time of quakeOvercast Clouds 8.5°C (47 F), humidity: 96%, wind: 9 m/s (17 kts) from SSW
Estimated seismic energy released4.5 x 1010 joules (12.4 megawatt hours, equivalent to 10.7 tons of TNT) | about seismic energy
Show interactive Map
[smaller] [bigger]
If you felt this quake (or if you were near the epicenter), please share your experience and submit a short "I felt it" report! Other users would love to hear about it!
If you did NOT feel the quake although you were in the area, please report it! Your contribution is valuable to earthquake science, seismic hazard analysis and mitigation efforts. You can use your device location or the map to indicate where you were during the earthquake. Thank you!

Data for the same earthquake reported by different agencies

Info: The more agencies report about the same quake and post similar data, the more confidence you can have in the data. It takes normally up to a few hours until earthquake parameters are calculated with near-optimum precision.
3.949 km82 Km SW of Atka, AlaskaUSGS
3.949 km90 Km SW of Atka, AlaskaEMSC

User reports for this quake

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
There are no user reports for this quake.
Volcanoes & Earthquakes - new app for Android

Earlier earthquakes in the same area

Try our free app!
Volcanoes & Earthquakes - new app for Android
Android | iOS version
Why is there advertising on this site?
Support us - Help us upgrade our services!
We truly love working to bring you the latest volcano and earthquake data from around the world. Maintaining our website and our free apps does require, however, considerable time and resources.
We need financing to increase hard- and software capacity as well as support our editor team. We're aiming to achieve uninterrupted service wherever an earthquake or volcano eruption unfolds, and your donations can make it happen! Every donation will be highly appreciated. If you find the information useful and would like to support our team in integrating further features, write great content, and in upgrading our soft- and hardware, please make a donation (PayPal or Online credit card payment).

Planned features:
  • Improved multilanguage support
  • Tsunami alerts
  • Faster responsiveness
Thanks to your past donations, these features have been added recently:
  • Earthquake archive from 1900 onwards
  • Detailed quake stats
  • Additional seismic data sources
Download and Upgrade the Volcanoes & Earthquakes app to get one of the fastest seismic and volcano alerts online:
Android | IOS
Thank you!
Copyrights: VolcanoDiscovery and other sources as noted.
Use of material: Most texts and images, in particular photographs, on this website are protected by copyright. Further reproduction and use of without authorization is usually not consented. If you are not sure or need licensing rights for photographs, for example for publications and commercial use, please contact us.