Abstract
The 8 September 1905 Calabria earthquake is the seismic event for which the Italian Seismic Catalogue shows the highest instrumental magnitude of the whole dataset. However, the reported Ms=7.47 was calculated over only two stations, and leaves room for a revision. In this work I provide a new estimate of the surface-wave magnitude of the earthquake calculated over sixteen individual values of magnitude from seven different stations. The new estimate is Ms=7.06±0.13, a value that is consistently lined up with other estimates provided by means of macroseismic or geological evidence. The novel estimate is stable despite alternative epicentral locations and different depths proposed for this event by several investigators. The net variation of almost half a unit magnitude implies a resizing of the seismogenic source of the event in the frame of the seismotectonics of the region, and highlights the strong need for a systematic revision of the instrumental magnitude estimates for several ‘historical’ earthquakes that occurred at the dawning of the instrumental seismology.
Highlights
The 8 September 1905 Calabria earthquake ranks among the ten most powerful events of the whole Italian seismic history [CPTI 15 Catalogue, Rovida et al, 2021] in terms of default magnitude (Mw = 6.95, which for this earthquake is calculated from the average of the macroseismic and instrumental magnitudes)
The net variation of almost half a unit magnitude implies a resizing of the seismogenic source of the event in the frame of the seismotectonics of the region, and highlights the strong need for a systematic revision of the instrumental magnitude estimates for several ‘historical’ earthquakes that occurred at the dawning of the instrumental seismology
Luigi Cucci of the Calabria region, prompted the author that there was room to attempt a revision of the seismological data available for the earthquake and provide an updated value of its surface-wave magnitude because 1) the rapid increase of organized catalogs and bulletins on the Internet has made it easier to access a greater number of seismological data than thirty years ago, 2) this instrumental data in particular is an important input for the evaluation of the magnitude of the 1905 event in the seismic Catalogue, and eventually for the assessment of the seismic hazard of the area
Summary
Such a value makes by far the 1905 earthquake the strongest event to have occurred during the instrumental era in Italy, even more than other seismic events that deeply affected the social, economic and environmental background of the Peninsula such as the 1908 Messina M = 7.10 [Pino et al, 2000], 1915 Avezzano M = 7.04 [Margottini et al, 1993], and 1980 Irpinia M = 6.81 [Rovida et al, 2021] earthquakes Such a high value probably derives from the shortage of seismological data associated with this earthquake and available to Margottini et al [1993] to build their dataset. Luigi Cucci of the Calabria region, prompted the author that there was room to attempt a revision of the seismological data available for the earthquake and provide an updated value of its surface-wave magnitude because 1) the rapid increase of organized catalogs and bulletins on the Internet has made it easier to access a greater number of seismological data than thirty years ago, 2) this instrumental data in particular is an important input for the evaluation of the magnitude of the 1905 event in the seismic Catalogue, and eventually for the assessment of the seismic hazard of the area
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
