Volcanoes in Alaska, Washington state, Oregon and Hawaii have been rumbling and even spewing lava, enough to spark a swarm of news stories. But despite the jolts and temblors, geologists say there’s no cause for alarm.
“Volcanoes can be unpredictable, and there’s always the chance that something bad will happen, but these recent seismic events along the Pacific Ring of Fire from Alaska to Washington to offshore Oregon are probably not directly related to each other,” said Natalia Ruppert, a seismologist with the U.S. Geological Survey’s Earthquake Science Center in Seattle.
“This is what volcanoes do,” she said. “They come to life for a while; sometimes the earthquake activity leads to an eruption and sometimes it doesn’t.”
Most of the U.S. volcanoes that have been making themselves known since spring woke up, shook themselves off and then fell back into slumber.
Two, one in Hawaii and one in Alaska, are in the midst of active – but relatively small and nonthreatening – eruptions.
Though it all might seem ominous, it isn’t. It’s simply part of life on a dynamic, seismically active planet.
There’s no direct connection between any of these, Ruppert said. “The distance between these (seismic) activity centers is thousands of miles.”
Recent U.S. volcanic activity
Though volcanoes have always been a part of the West Coast’s geography, it might seem this is an especially busy time for these mountains caused by fissures in the Earth’s crust that go down to the mantle below.
But seismologists and volcanologists are keeping a careful eye on them, Ruppert said. “This is why the federal government funds earthquake and volcano monitoring efforts through the Department of the Interior and USGS.”
Consider these events:
- More than 300 earthquakes hit Washington’s Mount Rainier in early July, the largest earthquake swarm ever recorded at the volcano. The swarm, a cluster of earthquakes in the same area in rapid succession, began July 8. Within two days, 334 earthquakes had been identified by the Pacific Northwest Seismic Network. But that’s not hugely unusual for the majestic volcano about 70 miles southeast of Seattle, which registered a similar swarm of quakes in 2009. Rainier’s last eruption, however, was about 1,000 years ago, Ruppert said.
- North of Washington state, Alaska has three volcanoes that are making themselves felt just now.
- As of July 10, Alaska’s Great Sitkin volcano in the Aleutian Islands was on a watch alert level, with lava erupting in the summit crater. Seismicity levels were low with occasional small earthquakes, the USGS reports. That eruption began in May 2021. Lava has been erupting at the summit since July 2021.
- On Alaska’s Kenai Peninsula, a flurry of small earthquakes shook the Iliamna volcano June 15. No surface activity was observed, however, and on July 1 the volcano was set at a normal alert code.
- North of Iliamna, another Alaskan volcano, Mount Spurr, has been experiencing swarms of shallow earthquakes since February. It’s now at a normal advisory level. For now, there’s little concern, Ruppert said.
- Heading down the West Coast, seismologists are also monitoring the Axial Seamount, a massive undersea volcano 300 miles off Oregon. It has been attracting attention for months as scientists prepare for an eruption they expect sometime in 2025. Because it’s so far underwater, only scientists using an array of instruments will know about the eruption.
The volcanoes are along what’s known as the Ring of Fire, a 25,000-mile-long horseshoe-shaped string of volcanoes and seismically active areas that stretches from the southern tip of South America, up along the West coast of the United States, across the coast of Alaska, down through Japan all the way to New Zealand.
It’s created by the Pacific tectonic plate sinking below the North American plate and is the most seismically and volcanically active zone in the world, according to the U.S. Geological Survey.
Eruptions in Hawaii
Far to the west in Hawaii, Mount Kilauea continues to erupt, though as of July 11 it has not been exhibiting the fountains of lava seen earlier in the month. On July 9, the USGS said the most recent eruption had ended.
Hawaii’s volcanoes are not part of the Ring of Fire. The island chain was (and still is) formed by a volcanic hot spot that has created 15 volcanoes that stretch 3,800 miles across the Pacific.
In Hawaii’s case, the volcanoes are the result of a heat source deep within the Earth’s mantle. The plume of magma coming from that hot spot in the ocean floor remains stationary as the Pacific Plate slowly – 2 to 4 inches a year – moves over the top of it.
That’s why Hawaii’s oldest volcanoes, on Kauai, are 5.5 million years old, while the newest, on the Big Island, are “only” 700,000 years old and still growing.
