ROME-A 4.2-magnitude earthquake shook Italy’s Campi Flegrei region west of Naples in the early hours Wednesday, in the biggest tremor in the area for 40 years, according to experts. The quake scared residents but caused no injuries or damage, according to the civil protection agency. The Campi Flegrei (Phlegraean Fields) is a vast volcano, though it is flat rather than cone shaped. While less well-known than nearby Vesuvius, a recent increase in activity has rattled nerves. The quake struck at 3:35 am (0135 GMT) at a depth of around three kilometres (nearly two miles), and was felt across much of Naples. “It was the biggest quake in the past 40 years,” Mauro Di Vito, head of Italy’s National Institute of Geophysics and Volcanology (INGV), told AFP.