INGV reported that multiple vents on Stromboli?s crater terrace were active during 15-21 July, though the exact number was unknown due to the unfavorable positions of the cameras. Vents in Area N (north crater area, NCA) produced low-to-medium-intensity explosions at a rate of 4-10 events per hour, ejecting lapilli and bombs less than 150 m high. The vents of Area C-S (South Central crater area) generated explosions of intensities variable between low and very high and at a rate of 6-17 events per hour. Tephra was ejected over 200 m high. Lava from Area C-S vents continued to travel down the S part of the Sciara del Fuoco shedding blocks that rolled all the way to the coastline.
Source: Sezione di Catania – Osservatorio Etneo (INGV)