Magnitude 3.9 quake under Etna's NE rift zone on 15 Aug 2026A shallow magnitude 3.9 quake occurred at 1.2 km depth under the NE rift zone of Etna volcano at 12:24:08 local time, with the epicenter at 2.8 km north from Piano Pernicana. This quake could be in connection with magma movements, potentially involving an activation of the north east rift zone.The effusive activity (lava flows) from the recently formed vents at elevations of 2750 m and 1990 m continued as of this morning, when personnel from the volcano observatory visited the volcano: The leading edge of the lava flows has reached an elevation of approximately 1600 m near Rocca Musarra, overriding previous flows.At 10:40 local time today (15 Aug 2026), a brief explosion occurred at the Northeast Crater, generating an ash plume that—according to dispersion forecast models—drifted southward. Currently, only weak ash emission, confined to the summit area, is continuing.Regarding seismic activity, at approximately 10:20 local time, the average volcanic tremor amplitude showed a very rapid, transient increase, reaching average levels and peaking at 10:40 local time. Subsequently, following a sudden drop, the tremor amplitude returned to the low range at 11:00, where it remains. As of this update, tremor seems to have increased again, probably in connection with the mentioned earthquake. This could indicate that something is about to change in the near future.Coinciding with the rise in tremor—and exclusively during this surge—the centroids of the tremor sources were located at the Northeast Crater, at an elevation of approximately 2000 m above sea level. Currently, the tremor source is located at the Voragine crater, at an elevation of approximately 2600 m above sea level. Starting at 10:26 local time, significant and temporary infrasonic activity was recorded for approximately half an hour, characterized by a succession of at least twenty high-amplitude infrasonic events, all localized at the Northeast Crater. At present, infrasonic activity is absent.We confirm the information previously reported: the recovery of the deformation observed via the tilt network and the consolidation of the deflation trend across the volcanic edifice, as observed by the GNSS network.Current tremor amplitude (image: INGV Catania)