Swarm of over 100 earthquakes hits Hanford nuclear site near Tri-Cities in Washington, U.S.
A series of over 100 shallow earthquakes have struck 48 km (30 miles) on the edge of the Hanford nuclear site northwest of Washington’s Tri-Cities since Saturday, September 21, 2024, with scientists attributing the tremors to tectonic activity near the Yakima Fold and Thrust Belt.
Earthquake swarm hits Hanford nuclear site near Tri-Cities in Washington, U.S. Image credit: TW/SAM, Google
Over 100 earthquakes have been recorded around 48 km (30 miles) northwest of the Tri-Cities area in Washington since Saturday. The quakes were recorded on the western edge of McGee Ranch, at the Hanford Reach National Monument.
Most of the quakes were below M2.0, with the largest being M2.9, which struck the north end of the swarm at 20:22 LT on Sunday, September 12. Most of them occurred at a depth of around 8 km (5 miles), classified as shallow crustal quakes.
The most recent quake occurred at 01:45 local time (LT) on Thursday, September 26. The quake occurred around 14 km (8.6 miles) northwest of Hanford. It was a M1.7 quake, with a depth of around 7.2 km (4.4 miles).
This area served as a security boundary for production facilities when the site was involved in producing plutonium for the United States’ nuclear weapons program.
As of 10:48 UTC on Thursday, September 26, there have been at least 129 earthquakes, although some smaller quakes may have gone undetected.
So far, there have been no reports of people feeling the quakes. According to Doug Gibbons, a research engineer for the Pacific Northwest Seismic Network, the quakes might not have been felt due to their remote location and low magnitude.
As there was no clear mainshock and only short intervals between the quakes, scientists are classifying them as a swarm. The quakes appear to have been caused by regular tectonic activity associated with the Yakima Fold and Thrust Belt on a fault line near Umatanum Ridge.
“This is a completely natural phenomenon. Although this swarm occurs just outside the Hanford Site, it has no connection to the radioactive waste stored there,” said Renate Hartog, manager of the Pacific Northwest Seismic Network.
References:
1 Swarms in Eastern Washington: are there fewer now than in the past? – PNSN -September 25, 2024
2 Recent Earthquakes – PNSN – Accessed on September 26, 2024
3 Swarm of 100+ earthquakes rattle edge of Hanford nuclear site northwest of Tri-Cities – Tri-City Herald – September 25, 2024
I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.
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