Mount Rainier rattled by a swarm of quakes
Why it matters: Even though scientists say there's no immediate cause for alarm, the uptick in seismic activity below what USGS calls the Cascade Range's " most dangerous volcano" has researchers and locals taking note.
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Axios
a day ago
- Axios
Mount Rainier rattled by a swarm of quakes
Scores of tiny earthquakes rattled Mount Rainier this week, marking the largest swarm of earthquakes at the mountain since 2009, according to the U.S. Geological Survey. Why it matters: Even though scientists say there's no immediate cause for alarm, the uptick in seismic activity below what USGS calls the Cascade Range's " most dangerous volcano" has researchers and locals taking note.
Yahoo
a day ago
- Yahoo
Hundreds of small earthquakes recorded in Mount Rainier swarm for first time since 2009
PORTLAND, Ore. (KOIN) — Hundreds of small earthquakes have been detected at Mount Rainier in Washington in an earthquake swarm, the largest number seen in more than 15 years, according to geologists. The U.S. Geological Survey says the and started to detect the earthquakes just before 1:30 a.m. on Tuesday. Robert Atrops sentenced to life in prison for 1988 murder of estranged wife The earthquakes are currently numbering in the 'several hundred small events,' with the largest one reaching a 1.7-magnitude and the earthquakes hitting at depths of between 1.2 and 3.7 miles. 'Earthquake swarms are relatively common at Mount Rainier, typically occurring 1–2 times per year but usually with many fewer events than have been detected so far during the current swarm,' officials with USGS said in a . The last time , when the mountain saw more than 1,000 earthquakes in a three-day period, with the largest clocking a magnitude of 2.3. Homeowner scammed out of $33K by Silverton roofing contractor, police say So what's the cause of these earthquakes on Mount Rainier? 'Earthquake swarms like this have been attributed to circulation of hydrothermal fluids that are interacting with preexisting faults at shallow levels below the summit of the volcano,' according to USGS. Mount Rainier's GPS stations have not recorded any changes in ground deformation, which is a warning sign for potential eruption. Mount Rainier, which has the tallest Cascade Range peak at 14,409 feet, is listed as an 'active, ice-clad stratovolcano,' with strong geologic evidence of an eruption about 1,000 years ago. Copyright 2025 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Yahoo
a day ago
- Yahoo
This Washington volcano just recorded its 'largest' earthquake swarm since 2009
Scientists have recorded the "largest" earthquake swarm at Mount Rainier in Washington state since 2009, the U.S. Geological Survey reported. The swarm at the second-most seismically active volcano in the northern Cascade Range started at 1:29 a.m. PT on July 8, the USGS reported in an X post. "Hundreds" of small quakes – the largest being a magnitude 1.7 — had been recorded as of 9 a.m. July 8, the USGS said, citing Pacific Northwest Seismic Network data. An exact cause of the swarms wasn't immediately reported, but the USGS said past swarms like these have been linked to "circulation of hydrothermal fluids beneath the summit interacting with preexisting faults." There were no reports that an eruption was imminent. The Pacific Northwest Seismic Network stated in an X post that there is "no indication that the level of activity is cause for concern, alert level and color code for Mount Rainier remain at GREEN/NORMAL." "Mount Rainier is well monitored by a dense network of seismic, infrasound, GPS, and webcam stations," the USGS said. "No other changes are apparent at the volcano at this time. (Cascades Volcano Observatory) and @PNSN1 will continue to monitor activity and issue additional notices as needed." Here's what to know about Mount Rainier. Mt. Rainier hasn't had a "significant eruption" in the past 500 years, according to the USGS's website. However, it is considered to be "potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle." Scientists detect a "few hundred" earthquakes at or near Mount Rainier in a typical year, the USGS reported. "Earthquakes associated with volcanic activity at Mount Rainier will not directly cause major damage to areas surrounding the volcano, but they will give scientists important information about magma movement beneath the volcano," according to the USGS. When "unusual earthquake activity" happens, scientists will use special instruments on and around the volcano to "monitor earthquakes, deformation, and other symptoms of volcanic unrest," the USGS said. This information is used to conclude whether any emergency alerts need to be given to the public, the agency said. Volcanically triggered earthquakes are usually smaller than earthquakes "caused by non-volcanic sources," according to the Pacific Northwest Seismic Network website. There are two kinds of volcanic earthquakes: volcano-tectonic earthquakes and long-period earthquakes. "Volcanic-tectonic earthquakes (VTs) are, simply put, caused by slip on a fault near a volcano," the website states. "Volcanoes are often found in areas of crustal weakness, and the volcano's mass itself adds to the regional strain. Most VT earthquakes have nothing to do with the volcano's magmatic system but occur in response to regional strain exerted in an area of weak faults." A swarm of these earthquakes does not indicate an "impending eruption," the website states. "However, if a significant introduction of new magma from depth occurs in the system, both VTs and long-period earthquakes are likely to be generated." Volcanically caused long-period earthquakes are "produced by vibrations generated by the movement of magma or other fluids within the volcano," the website states. These earthquakes "indicate magmatic activity and may be a precursor to an eruption." Long-period earthquakes were seen at Mount St. Helens "months in advance of the 1980 eruption" that killed 57 people, according to the website. Washington has five major volcanoes in the Cascade Range: Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams, according to the Washington State Department of Natural Resources. All five have a threat level of either "very high" or "high," according to a 2018 USGS hazard assessment report. There are about 170 potentially active volcanoes in the United States, according to the USGS. This article originally appeared on Kitsap Sun: This WA volcano just recorded its 'largest' earthquake swarm since '09
