The US Geological Survey has warned that ash from a freshly active volcano in the Northern Mariana Islands can could pose a serious threat to aviation.
The organisation says a swarm of seismic activity heralds renewed eruptive activity at Anatahan Volcano.
It says the current round of seismic activity peaked 10 days ago with about one small earthquake each minute and was similar in nature to that observed at other volcanoes before they erupted.
It says earthquakes are still occurring frequently, and steam and ash emissions and small explosions are likely to occur, throwing up clouds that could be hazardous to aircraft.
