Spatial relation between the 1908 Messina Straits earthquake slip and recent earthquake distribution

We re-analyze coseismic surface displacement data of the 1908 Messina earthquake, taking into account both correlated and uncorrelated uncertainties, to re-determine the slip distribution on the fault plane. Using a data set of earthquakes occurred at crustal depth in the Messina Straits between July 1988 and December 2004, we evidence a peculiar recent seismicity distribution inside the fault volume of the 1908 Messina Straits earthquake with respect to other regions in the area. An unusually large number of earthquakes is found in regions smoothly ringing slipped areas. Our results seem consistent with static Coulomb stress variations inside the fault volume and regional strain rate from GPS data, but could also suggest that in the last 15-20 years the 1908 earthquake source has been releasing strain accumulated in portions of it which did not rupture during the 1908 event.