title: Did the September 2010 (Darfield) earthquake trigger the February 2011 (Christchurch) event?
abstract: We have investigated the possible cause-and-effect relationship due to stress transfer between two earthquakes that occurred near Christchurch, New Zealand, in September 2010 and in February 2011. The Mw 7.1 Darfield (Canterbury) event took place along a previously unrecognized fault. The Mw 6.3 Christchurch earthquake, generated by a thrust fault, occurred approximately five months later, 6 km south-east of Christchurch's city center. We have first measured the surface displacement field to retrieve the geometries of the two seismic sources and the slip distribution. In order to assess whether the first earthquake increased the likelihood of occurrence of a second earthquake, we compute the Coulomb Failure Function (CFF). We find that the maximum CFF increase over the second fault plane is reached exactly around the hypocenter of the second earthquake. In this respect, we may conclude that the Darfield earthquake contributed to promote the rupture of the Christchurch fault.
authors.affiliation: Istituto Nazionale di Geofisica e Vulcanologia, via di Vigna Murata 605, 00143 Rome, Italy. salvatore.stramondo@ingv.it
authors.forename: Salvatore
authors.initials: S
authors.lastname: Stramondo
authors.forename: Christodoulos
authors.initials: C
authors.lastname: Kyriakopoulos
authors.forename: Christian
authors.initials: C
authors.lastname: Bignami
authors.forename: Marco
authors.initials: M
authors.lastname: Chini
authors.forename: Daniele
authors.initials: D
authors.lastname: Melini
authors.forename: Marco
authors.initials: M
authors.lastname: Moro
authors.forename: Matteo
authors.initials: M
authors.lastname: Picchiani
authors.forename: Michele
authors.initials: M
authors.lastname: Saroli
authors.forename: Enzo
authors.initials: E
authors.lastname: Boschi
mesh_terms: D055866:Earthquakes; D009520:New Zealand