In mid-2011 a strange episode occurred in Catania. In early summer, Mount Etna began to erupt, ash fell and lava flows could be seen clearly from the Sicilian city. Meanwhile, time speeded up, or at least that is what the city’s clocks were saying. For over a week, chronometers were confusing the inhabitants of the Catania area by gaining around 15 minutes per day.

The digital clocks on computers and household appliances in the east of the island had apparently gone mad. The authorities and island residents could see for themselves, and it was not a matter of isolated cases. Thousands of people took to the social media to join the clamour of ‘victims’ of this time-telling aberration.

For days, experts in computing and electronics attempted to find an explanation for the mysterious event. Etna was suspect number one. Changes in electromagnetic fields caused by the recent eruption seemed to be the most plausible explanation. However, in the end the cause was found to be simple enough: work on the underwater electricity cable linking Sicily and mainland Italy revealed that a slight variation in the frequency of the alternating current (from 50 Hz to 50.13 Hz) was causing the clocks to run fast.

The mystery of the erratic clocks finally had an explanation, an underwater one.