The National Seismic Network of the National Institute of Geophysics and Volcanology located an earthquake of magnitude 3.3 off the north-eastern coast of Sardinia at 11:03 today. "This is a rare but not unique event," we read on the INGV website. "This area of the sea, located between Olbia and Siniscola, has been affected by about twenty earthquakes in the last 40 years." "The cause of these earthquakes is to be attributed to the presence of extensional faults that border the Sardinian-Corsican block to the east with respect to the Tyrrhenian basin."