Finding of an historical document describing an eruption in the NW flank of Etna in July 1643 AD: timing, location and volcanic products

The eruptive activity of Etna volcano is well known in detail due to the integration of numerous geological and historical investigations. The study of historical sources of the volcano's activity started in the sixteenth century and has been reported in several catalogues of the eruptions published mainly in the eighteenth and nineteenth centuries. We have found a new document written in 1643 by the Fiscal Prosecutor of the High Court for the viceroy of Sicily in which he reported earthquakes occurring in the small town of Troina. The document also describes an eruption taking place in the Bronte region of Etna between 18 and 28 of July that was previously unknown in current historical catalogues, even those compiled by recent historiographical studies. This eruption clearly produced the volcanic products outcropping in the upper NW flank, shown on the new geological map of Etna as the Val di Cannizzola lava flow. The July 1643 eruption was a brief event with the emission of a roughly 2.7-km-long lava flow of very low volume (3-4 × 106 m3). It occurred in a period characterised instead by long-lasting and high-lava-volume eruptions that preceded the large and destructive 1669 eruption, the main event that has occurred on Etna in historical time.