Seismology: a new Italy-Japan international collaboration project, coordinated by OGS with the participation of INGV
The project was selected among the 11 admitted by the 2021-23 executive protocol for bilateral scientific-technological cooperation.
"Analysis of seismic sequences for the prediction of strong aftershocks", presented by the National Institute of Oceanography and Experimental Geophysics - OGS, has been included in the 2021-2023 Executive Protocol of bilateral scientific-technological cooperation between Italy and Japan. A total of 11 major projects in cutting-edge sectors have been admitted to participate in the agreement signed in Tokyo on 15 January by the Italian Ambassador to Japan, Giorgio Starace, and by Takeshi Nakane, Ambassador for Scientific Cooperation of the Ministry of Foreign Affairs Japanese Foreign.
The focus - The project presented by OGS foresees the close collaboration of two Italian research institutions, OGS and the National Institute of Geophysics and Volcanology (INGV), with the Japanese research institution The Institute of Statistical Mathematics (ISM ). By combining the skills of the researchers of the three bodies, who have already developed and applied specific algorithms for these purposes to some geographical areas, we aim to improve the estimate of the probability that after a strong earthquake the energy of the shocks that follow it, the so-called aftershocks, decay or, vice versa, other strong tremors may occur.
The phenomenon of aftershocks - A first particularly strong seismic shock is always associated with a series of subsequent aftershocks even after weeks or months in the same area which, as a rule, decrease in intensity. Among the first to propose an empirical relationship between the time that passes after a major earthquake and the decrease in frequency and intensity of aftershocks was the Japanese geologist and geophysicist Fusakichi Omori (1868 - 1923).
However, it may happen that an already intense shock is followed by similar responses or with even higher values. An example is what happened in the seismic event that hit the Amatrice-Norcia-Visso area. In fact, after the first earthquake of 24 on 2016 August 6.0, an even more intense phenomenon followed, with the 30 magnitude event of 2016 October 6.5. A similar situation occurred in the seismic events that occurred in Friuli where four months after the first shock of magnitude 6.5 on 6 May 1976, in September of the same year a swarm of earthquakes of magnitude up to 6.0 caused further destruction.
Importance - Aftershocks of significant magnitude can have further impacts on buildings, structures and infrastructures already damaged by previous earthquakes and entail new risks for the population. Having possible probabilistic indications on their occurrence is also useful in the management and planning of civil protection initiatives.
The comment - "The aim of the project is to study the cases in which, after a first earthquake of significant magnitude, there are further aftershocks of a magnitude similar to or even greater than that of the initial earthquake" explains Stefania Gentili, OGS researcher and project coordinator . These replicas, in fact, can cause significant damage to the building and infrastructural heritage already affected by the previous events, causing collapses and loss of human lives. “Having indications on the probability that these phenomena occur could therefore also be very important for civil protection activities in the management of seismic emergencies” Gentili points out.