Stromboli volcano (Italy), eruption update: new lava flows, pyroclastic flows on Sciara del Fuoco
8 March: Pause of the eruption
On 8 March, the lava flow from the 400 m vent below the 2003 lava plateau suddenly ceased almost completely. In the evening, the two branches of the flow and the lava delta at the sea were cooling, only a few red spots were visible from fractures on the surface, and a few glowing blocks and small amounts of sea water steam were still visible at the former entry points. At the vent itself, only a very weakly alimented flow extending perhaps 10-20 m was visible.
9 March: New lava flows and small pyroclastic flows accompanying the opening of a new fissure
Probably in the morning of 9 March, the lava effusion from the 400 m vent increased again, feeding a new lava flow, which has been flowing on top of the older flow. At our arrival at the scene at around 3pm, the flow front, about 5 m high and 20 m wide, was at about 200 m elevation. By the time we left at around 7pm, it had reached the base of the lava delta, and we think it will reach the sea during the night.
In the morning and early afternoon of today, frequent ash bursts were visible from the summit craters, probably related to deep seated typical strombolian activity. Some of the ash eruptions also ejected larger fragments as could be detected on photographs.
These ash emissions stopped when a new fissure vent opened at the Sciara del Fuoco, at about 500 m elevation and several 100s meters NW of the other vent, more or less beneath the former NW crater. This new vent announced its birth by a spot on the Sciara where a small and then increasing amounts of steam and then bluish gas were emitted, from around 3:30 pm onwards. At around 4 pm, we could observe a new, thin and weakly alimentated lava flow issuing from this point. The opening of the vent was accompanied by intense rockfall activity and another phenomenon which is briefly described: After the first appearance of lava, we observed low but dense clouds of white steam and brownish dust travelling downwards along a more or less streight path from the new vent. These "travelling steam and dust clouds" looked similar to small avalanches, propagated typically 100-200 m downhill and lasted around 10-20 seconds. This phenomenon reapeated several times during the following hour, and the clouds started at different points, and tendentially always more downhill where they finally came very close to the sea.
Although we are not able to tell whether these were small dust flows created by sliding loose material or rather a new fracture opening and propagating on the surface, we believe the latter interpretation to be right.
At around 5 pm, the lava flow had become about 200 m long and seemd to aquain speed. At this point, rockfalls of older material and from the new lava flow front triggered small, classic pyroclastic flows that reached the beach and were different from the propagating clouds described before.
From 6 pm onnwards, deteriorating weather and nightfall prevented further detailed observations, but the new flow in the NW sector of the Sciara had already reached an elevation of about 300 m.
It is also noted that large parts of the summit crater walls have collapsed leaving a bizarre arrangement of wall fragments and rock spines.
We gladly announce two new study&walking tours we can offer you in Italy: one to the Bay of Naples from 8-15 April and a two-weeks tour of the Eolian Islands from 6-18 May 2007. Both tours will be guided by our Italian geologist Marta who is a true insider in both areas.[details]
Because of the recent interesting volcanic activity at Merapi and Semeru volcano on Java, we point to two tours with open spaces for last-minute individual bookings:... [details]
Due to lack of participants, we decided to cancel the tour to North Sulawesi and postpone it to 2007. As an interesting alternative, we can offer a special trekking tour in Java and Bali from 5-20 August instead. There are two open spaces available.[details]