Pyroclastic density current (PDC): A turbulent, high-density flow composed of volcanic ash, lapilli and gases that descends rapidly along a volcano’s slope following an eruption.

Italy's Mount Etna erupted early Monday, causing tourists to flee as it spewed a massive plume of hot volcanic debris into the air. Videos circulating on social media purportedly show people on ...

Italy's Mount Etna, Europe's tallest volcano, erupted on June 2, causing tourists to seek safety. Several videos online have shown people fleeing as smoke and ash billowed from the side of the ...