Increased earthquake activity this week has prompted officials to warn that two long-dormant volcanoes in Alaska could be at greater risk of erupting.

On March 7, the Alaska Volcano Observatory raised the alert level for the Tanaga Volcano, which is located in the Western Aleutian Islands, after observing multiple earthquakes occurring under Tanaga Island, the observatory stated in a news release. On March 9, that alert was expanded to include the Takawangha volcano, also situated on the island.

A swarm of earthquakes occurring over the past few weeks has intensified at a remote Alaska volcano dormant for over a century, a possible indication of an impending eruption. https://t.co/dbnuJ8iDfD

— AP Climate (@AP_Climate) March 10, 2023

“We started seeing a whole lot of earthquakes occurring, one after the other, several per minute,” John Power, a research geophysicist with the U.S. Geological Survey stationed in Anchorage at the Alaska Volcano Observatory, told The Associated Press on March 9.

Power revealed that though there have been “hundreds” of earthquakes, none has been stronger than a 2.75 magnitude. Since the earthquakes are occurring beneath the summit of the volcano, however, it indicates “unrest,” prompting observers to raise the alert level, he told the outlet. (RELATED: Mount Etna Erupts, Massive Ash Cloud Looms Over Eastern Sicily)

“Whether or not this will lead to an eruption is something we can’t say at this point in time,” he said. “But we are concerned about it enough that we have gone and elevated the warning level,” Power stated.

The last reported eruption for Tanaga occurred in 1914, the press release stated. Instead of the flowing lava typically associated with volcanoes like Kilauea or Mauna Loa — both located in Hawaii — Tanaga would spew volcanic ash, Powers told AP. The eruptions, if they were to occur, would pose a serious threat to air travel, given that volcanic ash is angular and sharp and could potentially shut down an airplane engine, the outlet continued.