A small explosion shook Cleveland Volcano early Wednesday morning. There is no monitoring network on the volcano itself, but distant seismic stations picked up the blast, as they've picked up several similar explosions over the last few months.

Scientists at the Alaska Volcano Observatory said in a release that the eruption probably produced a small ash cloud. None of the recent explosions has interrupted air traffic, but Cleveland does lie on a major international and the Observatory is keeping the aviation alert level for the volcano at orange.