Earthquake Alert: M5.7 Event Detected in the United States

A magnitude 5.7 earthquake has been recorded 152 km SW of Adak, Alaska, occurring at 10:47 UTC on Friday, September 11, 2026. The earthquake's focal depth is 13.4 km. A tsunami advisory has been issued for this event. Coastal residents in the region should monitor official channels and move to higher ground if instructed to do so.

Earthquake Details

At a focal depth of 13.4 km, this is classified as a shallow earthquake (0–70 km). Shallow events are typically the most damaging: the seismic energy has less distance to travel before reaching the surface, resulting in stronger and more abrupt ground shaking at the epicentre.

A magnitude 5.7 earthquake is classified as a strong event and is capable of causing significant damage, particularly to older or poorly built structures. Strong earthquakes cause severe shaking that is difficult to stand through. Duration can reach 30–60 seconds. Widespread damage to ordinary buildings is common; even some well-built structures may sustain damage. Strong ground motion can trigger landslides, liquefaction of saturated soils, and rupturing of underground infrastructure.

Tsunami Risk: What You Need to Know

Not every large earthquake generates a tsunami. The key conditions required are: a large magnitude (generally M7.0+), a shallow focal depth under the ocean floor, and vertical displacement of the seafloor. Tsunamis can travel across ocean basins at speeds up to 800 km/h — as fast as a commercial aircraft — and may arrive at distant coastlines hours after the originating earthquake.

For coastal residents in the region: if you felt strong earthquake shaking, treat it as your natural warning and move immediately to higher ground. Do not wait for an official alert — the earthquake itself is your warning.

Regional Seismic Context

The United States experiences significant seismic activity primarily along the West Coast (Cascadia Subduction Zone, San Andreas Fault), in Alaska (subduction of the Pacific Plate), and in the intermountain West. The New Madrid Seismic Zone in the central US represents a significant intraplate hazard.

Alaska is the most seismically active US state, regularly producing large earthquakes including the 1964 Good Friday earthquake (M9.2 — the second largest ever recorded). California's San Andreas Fault system poses long-term risk to millions of residents. The USGS ShakeAlert early-warning system now covers the entire West Coast.

Safety Actions

The internationally recommended action during earthquake shaking is Drop, Cover, and Hold On: drop to your hands and knees, take cover under a sturdy table or desk (or protect your head with your arms if no shelter is available), and hold on until shaking stops. Do not run outside during shaking — most injuries occur when people attempt to move.

Fasten heavy furniture — bookshelves, water heaters, cabinets — to walls using earthquake straps. Store breakable items on lower shelves and heavy items closest to the floor. These simple steps significantly reduce the risk of injury from falling objects.

The USGS ShakeAlert system delivers earthquake warnings to smartphones via Wireless Emergency Alerts on the West Coast. California residents can also use the MyShake app. Drop, Cover, Hold On is the recommended protective action.

Energy Released

The energy released by a magnitude 5.7 earthquake is approximately the equivalent of a large mining explosion or small nuclear device. This is 32 times more energy than a magnitude 4.7 event — the logarithmic nature of the magnitude scale means each whole number increase represents about 32 times more energy.

This magnitude class poses a serious threat to older and poorly constructed buildings. Collapse is possible in the most vulnerable structures. Modern seismically designed buildings are expected to remain standing, though repair or demolition may be necessary after inspection.

Stay Updated

Monitor the Pacific Tsunami Warning Center (ptwc.weather.gov), your national meteorological or civil protection agency, and official government channels for the latest advisories. QuakeWatch provides real-time earthquake data on our live map — you can track this event and all aftershock activity as it develops.