Giovanni Battista Rizzo: The Vision of an Earth Physicist Between the Nineteenth and Twentieth Centuries

Giovanni Battista Rizzo (1863-1945) stands as one of the most significant figures in the history of Italian terrestrial physics. Born in Monastero di Vasco, in Piedmont, into a humble family, his determination and early aptitude allowed him to pursue university studies at the Royal University of Turin. There he trained as a physicist and quickly became an assistant at the Astronomical Observatory directed by Francesco Porro, a figure who strongly influenced his early scientific direction. From his youth, Rizzo devoted himself to pioneering research on absorption spectra, solar radiation measurements, and high-altitude meteorology, collaborating with international institutions and conducting fieldwork on Monte Rosa to measure solar intensity and the so-called solar constant. His career took a decisive turn when he moved to Messina in the early twentieth century. Appointed first to the Chair of Terrestrial Physics and later to that of Experimental Physics, Rizzo assumed the directorship of the Meteorological and Geodynamic Observatory of Messina in 1904. Immersed in this new Mediterranean context, he increasingly focused on geodynamics and seismology, disciplines then undergoing rapid development. The earthquakes of 1905 and, above all, the catastrophic event of 28 December 1908 profoundly shaped his personal and scientific trajectory. A direct witness to the tragedy, Rizzo was among the first to propose an energetic interpretation of earthquakes, challenging the purely descriptive approach of the Mercalli scale and anticipating the later need for a standardized physical measure of magnitude, which would only be formalized decades afterward. Beyond his scientific relevance, Rizzo played a decisive institutional role within the city of Messina. Appointed Rector of the University in 1911, a position he held until 1928, he led the complete reconstruction of the Ateneo after the earthquake. His tenure was marked by strategic vision and exceptional administrative commitment: under his leadership, the University was rebuilt from the ground up and reorganized, regaining a central cultural role in both the city and the region. He also promoted the establishment of new scientific institutes, including the School of Veterinary Medicine. In the later years of his career, after relocating to Naples, Rizzo taught Terrestrial Physics and contributed numerous entries to the Enciclopedia Italiana Treccani, especially in the fields of meteorology and atmospheric physics. Even in his mature scientific years, he remained attuned to the evolution of the discipline, clearly recognizing the need for an integrated approach to atmospheric, magnetic, and seismic phenomena. A figure of rare balance—combining academic rigor, scientific insight, and institutional responsibility—Giovanni Battista Rizzo left a profound legacy, though long overshadowed by the dramatic historical events of his era. His contributions to meteorology, geophysics, and to the development of the University of Messina remain essential chapters in the scientific history of early twentieth-century Italy.

___ Maria Teresa Caccamo, Salvatore Magazù