Scientists at the Alaska Volcano Observatory have lowered Cleveland Volcano’s aviation alert level. The restless Aleutian volcano exploded three times in a week earlier this month. None of the eruptions produced detectable ash plumes and the Observatory says there’s been no eruptive activity since March 13.

Cleveland lies on a major international flight path and scientists raised the alert level in January after a lava dome started growing in the volcano’s crater.  Gas build-up underneath lava domes can lead to explosive eruptions. Seismologist Steve McNutt told KUCB earlier this month that the recent explosions probably removed the forming dome.

The Observatory says in a release that sudden explosions exceeding 20,000 feet are still possible.  There’s no real-time seismic monitoring network on Cleveland, but the Observatory does have an alert system that can detect the lightning that often accompanies major ash clouds within minutes.