Together with Fusakichi Omori and Kenzo Sassa, Giuseppe Imbò is one of the founders of volcano seismology. Imbò's novel idea in volcanic tremor analysis was the introduction of what he called "numeri indici dell'intensità eruttiva" (numerical indices of the eruptive intensity). It was one of the first attempts to quantify eruptive activity on the basis of seismic data. The indices permitted him to establish correlations at Mt. Vesuvius between seismic observations and eruptive phenomena. He found significant differences in the character of the recorded seismic signals between pre- and post-eruptive phases of effusive and explosive activity of the March 1944 eruption of Vesuvius. According to Imbò, volcanic tremors are the product of a rhythmic hammering caused by the degassing magma normal to the vertically-oriented walls of the feeding conduits.