Figure 7
IP derived from infrasound detections at several stations for the July 3rd (a) and August 28th, 2019 (b) paroxysms at Stromboli. The vertical red line identifies the time of issuance of the VAA from Toulouse VAAC, while the pink line indicates the 300 m/s travel-time typical of stratospheric arrivals. The onset time of increased volcanic activity, based on the IP values exceeding the threshold of 60 for at least 20 min at each array, is shown by the red arrows. Such notification would have been possible at AMT, IS48 and IS26 for the July event, and at IS48 for the August event.
