Unusual eruptions

1.8.2003

End of the lava flow

5.4.2003

Effects of the explosion


Massive bomb and impact crater on Bastimento. Photo copyright Charles Riviere.	The same bomb, photo copyright Maurizio Ripepe. Stromboli village and Strombolicchio in the background.	Solar panels of our seismic station: This is why we have no data right now... Note fresh cow pat bombs in foreground. Photo M. Ripepe.	Telephoto image (heavily processed to increase contrast) from Stromboli village. Red boxes indicate impact craters (JA).

Crater on path leading to Ginostra's cemetery. The bomb was totally shattered by the force of the impact (JA).	The same crater seen in the opposite direction. «Stromboli» on the cemetery's wall indicates an old path towards Pizzo (JA).	Here a bomb destroyed a water cistern, a garden wall and a public footpath but fortunately narrowly missed the house in Ginostra (JA).	Damaged building in Ginostra. Luckily nobody was hurt during this traumatic event. Stromboli in the background (Photo Aeschlimann).

The explosion

Strong explosion at Stromboli in the morning of 5. April 2003, approximately at 9.15 local time (7.15 GMT). A big ash mushroom rose several hundreds meters over the mountain, and a loud noise was heard in the village. Rocks were heard falling along the slope of the mountain.


Photo Salvatore Carbone "Sasà" about 1 minute after the explosion. (from much further right - i.e. west - than the following pictures)	Photo Andreas Franssen 9h13 local time (7h13 GMT) from village Stromboli. The time of this photo is taken as T=0sec. for the following comparisons.	Section from image on the left: Thousands of bombs, some individual large bombs far right, one just before impact lower right, impacts on slope of volcano.	Photo Andreas Franssen T+20sec (relative times established using the internal clock of the digital camera). Rising eruption column.

Photo Andreas Franssen T+43sec. On the base of the eruption column new ash clouds begin to grow (consequence of bomb impacts or further eruptions?).	Photo Andreas Franssen T+69sec. The eruption cloud has risen to great heights and the "secondary" clouds follow.	Photo Andreas Franssen T+93sec. Now the secundary clouds have risen a lot as well. Smoke on the volcano's slopes is caused by minor bush fires.	Photo Andreas Franssen T+111sec. The northwesterly wind carries the eruption clouds towards the southeast. E-mail: "Andreas dot Franssen at t-online dot de"
	Photomosaic on the left: Assembled from photos submitted by Sergio Ballaro, Stromboli. You may need to scroll to the right in order to see all the individual pictures. Photos 1-6; 9-10 (c) Sergio Ballarò. Photos 7-8 (c) Sara Battaglia

Our seismometers recorded the event, but afterwards one of the sensors seems to be damaged:

Bombs covered the current eruption lava field, and fell even in the village of Ginostra. Fortunately nobody was injured, but various sorts of damage is reported. Two houses were hit by meter-sized bombs (one in the center of Ginostra village, one towards Secche di Lazzaro), and the cemetery wall was damaged. Impacts were also noticed on the Stromboli side, but did not reach the village (Thanks to Sergio Ballarò, Klaus Jaeger, Franco Zerilli, Salvatore Carbone, Jacopo Crimi, Andrea Ercolani).

From a report by Sonia Calvari, INGV, published via VOLCAN Listserv:

«On 5 April, at 9:12 am local time, scientists from INGV-CT were doing a helicopter flight for the daily surveys with a portable thermal camera. ... Three vents along this surface were feeding small lava flows, and the summit craters of the volcano were producing a very diluted gas cloud. A few minutes after the start of the survey, the gas plume coming out from the craters and moved west by the strong wind was suddenly crossed by a reddish ash emission, that we interpreted as further collapses within the craters. However, the red ash was soon substituted by juvenile, darker material coming out from crater NE crater. This formed a hot jet with cauliflower shape rapidly growing above the crater. Two or three seconds later, SW crater also produced a hot jet of juvenile material. The eruptive process then evolved very rapidly, with jets from NE and SW craters joining.

A very powerful explosion took place, which pushed the helicopter away from the crater, suddenly increasing its velocity by 30 knots/hour. A mushroom-shaped dark cloud rose from the craters, expanding vertically up to an elevation of about 2 km a.s.l., 1 km above the volcano's summit. The eruptive cloud was surrounded at its base by a dark-grey cloud similar to a base-surge, while it was still expanding vertically and assuming the mushroom shape. Bombs, ash and blocks fell on the NE flank of the volcano above 400 m elevation, causing burning of the vegetation. Most of the ejecta were carried west by the wind. Some fell on Ginostra and damaged two houses. No people were injured by the event.

Continuing the helicopter survey after the paroxysm, we could observe that the lava flow field on the upper Sciara del Fuoco was completely covered by a brown carpet of debris ejected from crater 1 during the initial phase of the event. A very thick steam cloud was rising from this site, suggesting vaporisation of wet material above the still active lava flows. In the meanwhile, several alternating black and reddish pulses were taking place, mainly from SW crater. Several fingers of light-brown debris were expanding from the NW flank of NE crater along the middle part of the Sciara del Fuoco. The upper part of the volcano above 700 m elevation was completely covered by a continuous carpet of pyroclastic products. Pizzo Sopra La Fossa showed on the north flank a number of new fractures concave towards north and extending between the summit of the volcano and the south base of NE crater. The presence of these fractures makes it possible that new landslides can occur on the summit of the volcano.

Within a few minutes from the start of the paroxysm, the upper Sciara del Fuoco showed active flows emerging from the carpet of debris covering the lava flow field. The explosive event caused abundant emission of the so-called "golden pumice" mixed with little brown scoria. ... A helicopter survey carried out on 8 April showed four active vents pouring out lava on the upper Sciara del Fuoco at 590 m a.s.l.. Two of the flows were expanding along the middle Sciara del Fuoco, causing detachment of blocks from the flow front and little rock falls reaching the sea. Within the summit craters a thick carpet of debris has accumulated following the paroxysm of 5 April. This has reduced the craters depth of about 50 m thickness, causing partial obstruction.»

March 2003

During the whole month of March 2003 the lava flows and moderate-sized rockfalls continued to descend along the Sciara del Fuoco. Thanks to Sergio Ballarò we can offer some sample photos of the March 2003 eruptive activity.


Photo Sergio Ballarò. Along the steep slope of Sciara, the smoke raised by the small rockfalls almost continuously descending.	Photo Sergio Ballarò. The morphology of NE crater has changed considerably. In the middle a dyke-like structure.	Photo Sergio Ballarò. An overview of the lava field of the 2002-2003 eruption.	Photo Sergio Ballarò. Detail of one of the effusive vents within the lava field established below NE crater.