Magnitude 4.9 Light Earthquake Strikes Near Adak, Alaska
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A magnitude 4.9 earthquake occurred 120 km west-southwest of Adak, Alaska, on February 18, 2026. The shallow quake did not trigger a tsunami advisory.
What this USGS earthquake report tells you, and what most readers miss
This notice was issued by USGS on April 6, 2026 and geographically references Alaska. Its severity classification of "medium" signals how the issuing agency weighs the risk of harm if no action is taken - "critical" and "high" tier alerts typically carry direct consumer actions, while "medium" and "low" tend toward informational guidance or monitoring advisories. The category it belongs to - Earthquakes - determines the monitoring protocol behind it, which shapes what follow-up action (checking for structural damage, watching for aftershocks, reviewing local building codes) is relevant and which agency holds authority over the assessment.
Most readers skim a notice like this, check whether they are personally affected, and move on. The more useful lens is to verify its scope, source, and timestamp, then compare related notices without assuming that one record proves a broader trend.
Areazine pairs this record with the original agency URL so you can check the primary source before acting. Its related labels are earthquake, seismic, usgs, Alaska.
What Happened
A light earthquake with a magnitude of 4.9 ml occurred on Wednesday, February 18, 2026, at 23:12:50 UTC (approximately 1:12 PM local time in Adak). The event was centered approximately 120 km west-southwest of Adak, Alaska, at a shallow depth of 18.6 km.
Location Details
The seismic event was located at coordinates 51.288°N and 178.094°W. The recorded depth of 18.6 km is classified as shallow. Shallow earthquakes—those occurring at depths of less than 20 km—are typically felt more distinctly at the surface than deeper seismic events of the same magnitude.
Impact Assessment
According to the U.S. Geological Survey (USGS), there are currently no felt reports associated with this event. The Modified Mercalli Intensity (MMI) was calculated at 4.366, which corresponds to light shaking. Data indicates there is no tsunami advisory, watch, or warning in effect. No specific PAGER alert level (color) was issued for this event.
What You Should Know
A magnitude 4.9 earthquake is categorized as a "light" earthquake. While these events cause noticeable shaking and are frequently felt, they rarely result in significant structural damage. Residents in the Aleutian Islands region should be aware that aftershocks are a routine possibility following an event of this size. In the event of further shaking, safety officials recommend you "Drop, Cover, and Hold On."
Source
Data and attribution provided by the USGS Earthquake Hazards Program.
Original source: USGS Official Notice ↗
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