The National Institute of Geophysics and Volcanology, Etneo Observatory, informs that this November 16 at 09:17:50 UTC, an explosion, considered as major, was observed at Stromboli, in the center-south zone, accompanied by a plume ash about 1,000 meters high.
A small pyroclastic flow rolled down the Scira del Fuoco to sea level, where it continued for some 200 meters.
Shortly after the eruption, ashes and lapilli fell; the color of the particles, a few mm., are brown to red-brown (old materials present in the vent), however a small amount of lighter pumice is also present in the ash (small fraction of fresh magma which has produces the rash).
From the seismic point of view, the phenomenon, clearly visible on all the seismic stations of Stromboli, is characterized by a sequence of explosive events which started at 9:17 (UTC) for a duration of 4 minutes. Regarding the magnitude of the volcanic earthquake there are no significant variations.
N.B. The paroxysmal explosion warning system was and is still in operation. This explosion (major and not paroxysmal) exceeded the amplitude criterion (0.3 microrad) provided by the Paroxysmal Early-Warning system but not that on the duration of the ground inflation which precedes the paroxysmal explosions, for which the threshold was not exceeded of 0.85 provided by the automatic system to trigger the warning system
Sources INGV OE & LGS
Stromboli - major explosion 16.11.2020 - video INGV OE
A moderate explosion occurred at Santiaguito on November 16 at 7.15 am local time; it was accompanied by a plume of ash at 3,600 m. asl. and pyroclastic flows on the sides of the Caliente dome. The most important flow moved towards the upper part of the bed of the Rio San Isidro, on the SW flank of the dome.
The ashes dispersed in a SW direction towards the area of San Marcos Palajuno and its surroundings.
This type of event is due to the unstable accumulation of blocky lava and fine pyroclasts in the dome of Caliente Dome, causing it to detach and channel in the form of avalanches and pyroclastic flows.
Sources: Insivumeh & Conred
Santiaguito -16.11.2020 - explosion and pyroclastic flows at the Caliente dome - photo Edgar Cabrera, COLRED Finca El Faro
Santiaguito -16.11.2020 - explosion and pyroclastic flows at the Caliente dome and seismogram - Doc. Insivumeh
At Sinabung, the PVMBG shows a declining seismicity curve.
For the day of November 16, the observatory records:
- 21 collapse / avalanche earthquakes
- 1 low frequency earthquake
- 1 earthquake related to a pyroclastic flow at 4:29 p.m., which moved over 2,000 meters towards the ESE, and left an imprint of 110mm in amplitude, lasting 240 sec.
In Semeru, on Java, an image from the Sentinel-2 L2A bands 12,11,4 satellite of November 16, 2020 shows the presence of hot spots at the summit crater and on the flow on the side of the volcano.
The PVMBG informs for November 14:
- 81 eruption earthquakes
- 4 blast / emission earthquakes
- 1 local tectonic earthquake
- 3 distant tectonic earthquakes.
Sources: PVMBG & Sentinel-2