Continuing lava flows
Update Sat 09 Aug 10:47
The lava effusion continues at decreasing, but still considerable rate. When seen yesterday evening, only one channel, 5-10 m wide was still entering the sea at 10 m wide front, while there had been up to 7 branches reaching the shore in the area west of or partially covering the 2007 lava delta. Small explosions were occurring at the sea entry.
Stromboli's lava flows yesterday night
Several lava branches were still weakly active on the upper Sciara, causing many incandescent rockfalls.
It appears that a part of the NE flank of the NE crater has collapsed and that the new effusive vent is located at its northern base, at approx. 700 m elevation. Thus, being lower than the summit vents, it is able to effectively drain the upper part of the volcano's plumbing system, which explains why no explosions were observed at the summit craters.
Lava flows reaching the sea
Update Thu 07 Aug 17:37
from INGV's update this morning:
Lava flows reaching the sea this morning (INGV thermal webcam)
At 05:16 GMT on 7 August, the second abundant lava flow began as an overflow from the northern terrace, quickly covered the entire "plateau" at 600 m altitude, and then descended the Sciara in several branches.
In a short time, the lava flows reached the sea in several fronts. The activity was accompanied by numerous landslides. The left image, taken by the camera SCT at 06:23 GMT on August 7, shows three lava flows entering the sea, while two others, in the foreground, are close to reaching the coastline.
Update Thu 07 Aug 10:59The lava flow is entering the sea and has covered the 2007 lava flow.
The new lava flow seen on the thermal webcam on the Sciara del Fuoco (INGV)
Different from the overflows during July and yesterday evening, this time, the northern side of the NE crater was affected. First, it seems that a significant collapse occurred, accompanying the opening of a new effusive located at the northern base or flank of the NE crater. How much of the crater itself was affected is difficult to judge at this point.
The beginning of the new flow
A collapse event at 05:18 marks the opening of the vent:
Culture Volcan posted a nice illustration showing the topography of Stromboli, the Sciara del Fuoco with the paths of yesterday's (yellow) and this morning's (red) lava flows:
Topography of yesterday's and this morning's lava flows of Stromboli
15 minutes later, the lava flow front arrives at the edge of the 2002-3 plateau.
Immediately after this event, a large thermal anomaly, likely a lava flow, spreads down the north side of the NE cone. As the topography image shows, the area north of the NE crater where the new flow headed to is occupied by a flat plateau created by the 2002-3 lava flows. It would force lava flows to pool and spread out horizontally, and prevent them from quickly reaching the steep part of the slope of the Sciara. However, only 15 minutes later, a broad front of lava arrives at the edge of the plateau and then rapidly descends the steep slope. This and the size of the lava flow suggest a very high effusion rate, many times larger than any of those overflows observed in recent years. It can be assumed that the flow has entered the sea shortly after. Updates will be posted on top as news arrive.
Within minutes, the lava then descends the Sciara del Fuoco
Stromboli volcano (Eolian Islands, Italy): major lava flow
Thursday Aug 07, 2014 05:56 AM | VON: T
Thermal image of the large lava flow from Stromboli after a collapse (?)
Thermal image of the same area immediately before, showing the cooling flow from last night
This post will be updated on this special page.
Seismic signal this morning, showing the collapse and onset of the new lava flow from 05:15 (STR8 station, INGV)
A major event has taken place about half an hour ago. It seems - judging from available webcam imagery - that a new vent opened at the NE base of the crater and/or a significant part of the crater terrace might have collapsed and left space for a larger lava flow descending the Sciara.
Videos (time-lapse from INGV's webcam on Sciara del Fuoco, thermal and visible):
Yesterday's new lava flow had started as an overflow from the notch between the two prominent N1 and N2 vents, commonly known as the NE crater. A series of smaller and larger collapse events had occurred during the day, most notably at 14:06, 14:24 and 14:51.
These events likely coincide with the beginning of the lava flow. The flow itself, similar to the ones that had occurred in July, remained active until the early morning, but had significantly decreased by then.
A picture taken from the sea on the evening shows that the flow had not reached the sea:
Alert of elevated activity since 5 August
Already on 5 August, Civil Protection raised the alert status to "elevated", with access to the summit closed. Monitoring detected very high levels of explosive activity from the NE and NW craters and strong degassing from the central vents.
Rockfalls / lava flow on the Sciara on 6 Aug afternoon (image: Civil Protection)
Between 09:13 and 17:23 that day, deformation in the outer flanks of the NE crater was detected - the area where the landslide and new flow started on 7 Aug.