After the ash emissions of 18-21 August 2019, Etna resumed its activity starting from 4 September 2019 from the NE Crater (NEC), producing sporadic and modest ash emissions. In the following days (in particular from 8 September) Strombolian activity was observed which produced weak and intermittent flashes in the night hours which gradually became more intense and continuous. Weak emissions of very diluted ash were observed during the day. On 9 September, the intense cloud cover allowed continuous observations of the eruptive activity only starting around 18:00 UTC. In particular, the analysis of the data recorded by the cameras operating in the visible and thermal infrared spectrum installed on the western (EBT), southern (EMOV, EMOH and EMOT) and eastern (EMCH and EMCT) slopes made it possible to link the eruptive scenario to the NEC (Fig. 1).
Fig. 1: Strombolian activity at the NE Crater observed between the evening of 9 September and the morning of 10 September 2019 by the surveillance cameras of INGV-OE
Between 18:00 UTC on 9 September and 05:00 UTC on 10 September, the NEC fueled continuous Strombolian activity which produced diluted ash emissions which rapidly dispersed into the atmosphere under the effect of winds.
During the last 24 hours, the parameters of the volcanic tremor have presented some evident variations, mainly regarding its amplitude and its location.
After the important, high values recorded during the increase in the early hours of 8 September, the average amplitude of the volcanic tremor underwent a significant, progressive decrease (Fig. 2). It reached clearly more contained values, within the average level, in the last hours of the same day 8. Starting from the first hours of yesterday (9 September), the average amplitude of the tremor showed a clear and sudden increase, reaching very already important from 6 am and reporting the maximum values between 11 yesterday and 2 today. At present, the amplitude of the tremor is characterized by some fluctuations, with average values tending towards a slight decrease, but which nevertheless remain within the high level.
Fig. 2: Time course of the average volcanic tremor amplitude recorded in the last week at the ECPN summit station (Piano Crater, altitude 3035m) according to three amplitude levels (low=green, medium=yellow, high=red).
Other evidence deriving from geophysical data and geochemical data are reported in the legible press release at the link ....
Furthermore, today (10-9-2019) at 10:31, the stations of the Seismic Network of the National Institute of Geophysics and Volcanology, Observatory of Etna, recorded an earthquake with a local magnitude of 2.5 (±0.2 ).
The event was located 0.8 km SW from Fiumefreddo di Sicilia (CT).
The hypocentral coordinates are as follows:
latitude 37.788 longitude 15.197 (epicentral error 0.4 km)
depth 7.4 km (depth error 0.4 km)
The three locations closest to the epicenter are (in order of distance):
1) Fiumefreddo of Sicily (CT) (0.8 km)
2) Piedimonte Etneo (CT) (2.7 km)
3) Mascali (CT) (3.5 km)