ANCHORAGE / TOKYO — A series of magnitude 5.0 and stronger earthquakes struck multiple sections of the Pacific Rim within a 24-hour period, underscoring ongoing tectonic activity along the world’s most seismically active region, according to data from the U.S. Geological Survey (USGS).
The strongest event occurred early Thursday, when a magnitude 5.9 earthquake struck 271 kilometers east-southeast of Attu Station, Alaska, at a depth of about 41 kilometers. The quake was centered in the Aleutian subduction zone, where the Pacific Plate dives beneath the North American Plate. No tsunami warnings were issued, and impacts were expected to be minimal due to the remote offshore location.
Earlier, a magnitude 5.0 earthquake was recorded 197 kilometers east-northeast of Petropavlovsk-Kamchatsky, Russia, at a shallow depth of 10 kilometers. That quake occurred along the seismically active Kamchatka Peninsula, part of the same Pacific Plate boundary system.
Another magnitude 5.1 earthquake struck the Kuril Islands, northeast of Japan, also at a depth of about 10 kilometers. The Kuril arc is a frequent source of moderate to strong earthquakes due to ongoing subduction of the Pacific Plate beneath the Okhotsk Plate.
Completing the sequence, a magnitude 5.1 earthquake was reported 16 kilometers west-northwest of Shiojiri, Japan, at a depth of approximately 6.7 kilometers. The quake was felt locally, with the USGS estimating light shaking (Intensity III) in nearby communities. No damage or injuries were reported.
Seismologists emphasize that while these earthquakes are not directly linked, they all occurred along the broader Pacific Ring of Fire, a horseshoe-shaped zone that accounts for about 90 percent of the world’s earthquakes. Clusters of magnitude 5 earthquakes are common in this region and do not necessarily indicate a larger event is imminent.
The USGS noted that aftershock probabilities remain low for large events in each area, and no tsunami threats were associated with any of the earthquakes.
