Scientists have raised the threat level at Alaska’s Cleveland volcano from yellow to orange after detecting a low-level eruption on Saturday morning – sparking fears that the rumble could be a precursor to a bigger eruption. Jessica Larsen, with the University of Alaska Fairbanks Geophysical Institute, said scientists had not seen evidence for ash in satellite images. KTVA.com reports: “We detected an explosion using infrasound equipment, which basically senses air pressure and it can detect explosions from really far away, like in remote volcanoes like Cleveland,” said Jessica Larsen, with the University of Alaska Fairbanks Geophysical Institute. “And then it also showed up on the seismic data. So we would classify that as an eruption. Usually these eruptions from Cleveland can be short duration explosions and then some variable amount of time might pass before we see another one.” Larsen said there was no evidence of increased activity at the volcano in the days leading up to the eruption. AVO was not able to get an immediate look at the volcano, as cloud coverage in the area prevented satellite viewing. So far no ash cloud has been reported and Larsen said no aviation warnings have been issued. The volcano’s color [...]