Fabris was a painter of Italian descent, active in England and Naples. Pietro is best known for work he completed for the dilettante geologist, the diplomat Sir William Hamilton, which included a number of engravings based on his paintings that depicted contemporary volcanic activity collected in two books, Observations on Mount Vesuvius, Mount Etna, &c. (London, 1774) and Campi Phlegraei: Observations on the Volcanoes of the Two Sicilies (Naples, 1776).