What Is an Exceptional Earthquake?

Abstract

On 8 September 2020, the Italian media reported that the Court of Rieti, central Italy, found guilty with imprisonment between five and nine years the five defendants for the collapse of two public housing buildings and the death of 18 people, following the 24 August 2016 Mw 6.0 Amatrice earthquake; the first of a long-lasting earth- quake sequence featuring nine Mw > 5 events, the largest being an Mw 6.5 near the town of Norcia (Fig. 1b,c). The court rejected a claim of exceptionality of the ground shaking put forward by the defendants and stated that the collapse was caused by “... well-identified design and building flaws, violating specific legal provisions and technical construction standards....”