An Alaskan volcano that has been inactive for more than 100 years is showing signs of rumbling, according to scientists.

However, there’s a chance that the activity could be signs of a pending avalanche, rather than a volcanic eruption, NASA said.

The Iliamna volcano, located near the Cook Inlet in southern Alaska, last erupted in 1867, but would still rumble every few years due to avalanches large enough to register on nearby seismic and infrasound instruments, according to NASA.