The top of the volcano exploded, sending a gigantic column of ash four or five kilometres (2.5-3 miles) into the sky. Mount Stromboli, off the north coast of Sicily, is one of the most active volcanoes in the world. On 11 July, it produced a paroxysm – a type of powerful eruption that interrupts a period of milder volcanic activity. In the villages nestled around the foot of the volcano, warning sirens blared.

The paroxysm occurred shortly after 2pm local time and news of the event quickly began to spread online. Shortly after the explosion, two dozen or so volcanologists around Europe were due to attend one of their regular meetings. Chiara Maria Petrone, a volcano petrologist at the Natural History Museum in the UK, joined the session online.