Stromboli activity update, 27 October 2010
Shortly after 07.35 h GMT on 17 October 2010, continuous spattering started from what appared to be one of the two vents located at the northern extremity of the crater terrace of Stromboli. This activity continued for nearly two hours before gradually ceasing, and was followed by the intermittent explosive activity that is typical for this volcano.
Photograph of the crater terrace of Stromboli taken by F. Ciancitto from the Pizzo sopra la Fossa on 24 October 2010. The hornito that was the site of intense spattering from 18 October onward is indicated by a red circle and arrow; from a vent at its base a lava flow is seen expanding across the crater terrace and forming a small, fan-shaped lava delta in the right foreground.
During the night between 18 and 19 October, the hornito located in the southern portion (on the side of the Sciara) of the crater terrace, began to produce vigorous spattering followed by the opening of a new vent at its base, from which issued a small lava flow. This lava flow travelled northward across the crater terrace, running against the base of the northern intracrater cone, after which it passed between this cone and the scoria cone of the southern vents (see the photo above). It then descended into a depression to the east, where it formed small, fan-shaped delta. The effusive activity continued at a low rate until the evening of 23 October. On 24 October, the hornito showed only weak activity, but after midnight vigorous spattering resumed, which was difficult to observed on 25 October due to the poor weather conditions at Stromboli's summit.
From the evening of 23 October on, with the cessation of the intracrater lava emission, explosive activity from the northernmost vent in the northern portion of the crater terrace increased in intensity. During the night, and still more vigorously during the morning of 24 October, a series of strong explosions occurred, which produced coarse material (bombs and incandescent lava fragments) that fell outside the crater, covering the rim of the crater terrace and sliding down the Sciara del Fuoco. This phase of activity ended abruptly during the late forenoon (10.38 GMT) and was followed by the normal explosive activity that had persisted during the preceding days.
The two vents on the Pizzo side of the southern vent area produced medium-intensity explosions with ejection of fine-grained material, and ash plumes rose less than 150 m high. Explosions occured with a mean frequency of 2-4 events per hour. L
As of 27 October, the explosive activity of Stromboli is continuing at normal, low-to-medium levels.