31 km SE of Chickaloon, Alaska
A magnitude 3.5 earthquake struck near 31 km SE of Chickaloon, Alaska on August 20, 2026 at 5:58 PM UTC. The event occurred at a depth of 12.4 km, releasing energy equivalent to 2.7 tons of TNT. This is classified as a Minor earthquake on the Richter magnitude scale. The hypocenter depth is categorized as Shallow (< 70 km). Shaking from this event may have been felt within an estimated radius of 11 km from the epicenter.
Magnitude Scale
Depth Gauge
Intensity
('III', 'Felt indoors; hanging objects swing.')
Impact Assessment
3 people reported feeling this earthquake through the USGS "Did You Feel It?" system.
This earthquake has been reviewed and confirmed by USGS seismologists.
Nearby Earthquakes
| Mag | Place | Time |
|---|---|---|
| 1.3 | 62 km N of Chickaloon, Alaska | 2 hours, 29 minutes ago |
| 1.7 | 14 km ENE of Willow, Alaska | 7 hours, 35 minutes ago |
| 1.3 | 14 km ESE of Susitna North, Alaska | 9 hours, 13 minutes ago |
| 1.6 | 37 km NNE of Chenega, Alaska | 9 hours, 54 minutes ago |
| 1.9 | 4 km E of Whittier, Alaska | 12 hours, 10 minutes ago |
Frequently Asked Questions
Yes. A magnitude 3.5 (Minor) earthquake was recorded near 31 km SE of Chickaloon, Alaska on August 20, 2026 at a depth of 12.4 km (shallow (< 70 km)).
The earthquake had a magnitude of 3.5, classified as "Minor" on the magnitude scale. It released energy equivalent to approximately 2.7 tons of TNT.
The earthquake occurred at a depth of 12.4 km, which is considered shallow (< 70 km). Shallow earthquakes typically cause stronger shaking near the epicenter.
The tsunami risk for this earthquake was assessed as none. Tsunami generation typically requires a magnitude 7.0+ shallow earthquake beneath or near the ocean floor.
Earthquake depth (also called focal depth or hypocentral depth) is the vertical distance from the Earth's surface to where the earthquake rupture begins. Shallow earthquakes (0-70 km) tend to cause more surface damage, intermediate (70-300 km) are felt over wider areas, and deep earthquakes (300-700 km) rarely cause significant damage at the surface.
The Modified Mercalli Intensity (MMI) scale measures the effects of an earthquake at a specific location, ranging from I (not felt) to XII (total destruction). Unlike magnitude, which measures energy released at the source, MMI describes how strongly shaking is felt and what damage occurs at a given place.
The felt radius is the maximum distance from an earthquake's epicenter at which ground shaking can be perceived by people. It depends primarily on magnitude, depth, and local geology. A shallow M6.0 earthquake might be felt 300-500 km away, while a deep M6.0 might be felt over a wider but less intense area.
Earthquake energy is often expressed in TNT equivalents for intuitive comparison. A M5.0 earthquake releases energy equivalent to about 32,000 tons of TNT (a small nuclear weapon), while a M9.0 releases 32 billion tons of TNT — roughly 1,000 times more than the largest nuclear weapon ever detonated.
Tsunami generation requires three conditions: the earthquake must be large (typically M7.0+), shallow (under 100 km depth), and occur beneath or near the ocean floor with significant vertical displacement. Strike-slip faults rarely generate tsunamis because they move horizontally rather than vertically.