Although experts believe “the probability of a volcanic eruption is relatively low,” the relentless inflation and recent shaking of Italy's Campi Flegrei caldera raise questions for experts—and locals.
As a result, an increase in the steepness or bulging of a volcano’s slope may signal an impending eruption. To detect the inflation of a volcanic cone, a tilt meter, a device like a carpenter’s level, is used. As magma rises, it pushes aside fractured rock, enlarging the fractures...