Stromboli volcano, Italy



	The "normal" activity of Stromboli consists of discrete small explosions that eject glowing lava fragments a few tens of meters high. This is known as "Strombolian" activity and applied worldwide to eruptions of this type. These photographs show night (top) and daylight (bottom) views of Strombolian activity at a small cone built up within one of the summit craters of Stromboli. 22 August 1994

Stromboli is one of the few volcanoes on earth that display continuous eruptive activity (also called "persistent" activity) over a period longer than a few years or decades. Its historic record goes back to more than 2500 years before present, and there is evidence that its persistent activity has been going on for as long as 5000 years (recent studies, however, indicate that this activity began only during the first millennium A.D.).
Most of this activity is of a very moderate size, consisting of brief and small bursts of glowing lava fragments to heights of rarely more than 150 m above the vents. Occasionally, there are periods of stronger, more continuous activity, with fountaining lasting several hours, violent ejection of blocks and large bombs, and, still more rarely, lava outflow. Twice during the 20th century (in 1919 and 1930) there have been large eruptions that caused significant damage and killed persons even at considerable distance from the craters. Several explosions in the past few years have surprised groups of tourists who were in the summit area, causing various accidents as people began to run around in fear and consternation. Unfortunately, one person was killed by such an event in late 2001. Pure luck has prevented that tourists were in areas at risk when the volcano entered into a serious eruptive crisis at the end of 2002, and when a very powerful explosion occurred on 5 April 2003.
Eruptions that produce lava flows occur at very irregular intervals that may vary from a few years to more than 15 years. The most recent of these eruptions occurred in 1975, 1985-1986, and 2002-2003. Generally such eruptions are considered rather harmless, because lava flows remain confined to a large depression formed during several sector collapses during the past 13,000 years, which hosts the active craters. However, the 2002-2003 eruption was accompanied by a landslide, which triggered a tsunami (a large wave caused by the displacement of large rock volumes below the sea or avalanches into the sea). As a consequence, the portions of the main village on the island closer to the coast suffered substantial damage, and for the first time in history the entire population of the island was evacuated.
Although it has been visited almost daily by numerous people in the past thirty years or so, documentation of the activity of Stromboli has been far from complete until very recently. Thus, as recently as August 1994, the emission of a small volume of lava from the northernmost of Stromboli's presently three craters was only revealed several months later. The volcano is now being monitored visually by several automatic telecameras maintained by the Catania section of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) whose task is the surveillance of seismic and volcanic activity in Sicily. Seismic stations are maintained by the monitoring network of the INGV and several other institutes such as the Dipartimento di Georisorse e Territorio of the University of Udine. These stations are continuously transmitting data to those institutes. However, as surprisingly as this might seem, much of the eruptive dynamics of Stromboli are still not fully understood, and there is a pressing need to further research on the way this volcano works. The complex events during the major effusive eruption of 2002-2003 have been a serious challenge both for scientists and civil defense personnel.
These Stromboli pages will give some general information about the volcano and deal with some specific aspects of its recent eruptive history. Particular attention is devoted to the period since 1985 which includes many personal experiences by myself, and which has proved to be the best documented period in the history of Stromboli. As you will note these pages are densely interwoven with those of the companion site "Stromboli On-line", as both "Stromboli On-line" and "Italy's Volcanoes" are intended to complement each other.

The first part of the Stromboli section introduces you to the geographical setting of the volcano, with information on the location and morphology of the island. From there you may proceed to the geological evolution of the volcano, which is anything else than simple. The eruptive activity during the historical period is reviewed on a number of pages, starting with a simple list of the major eruptive events known during that period, and then showing a series of photos taken on the volcano before 1930, a critical year during the recent history of the volcano. The powerful and destructive eruption of 1930 is described in detail, followed by an overview of the activity between 1930 and 1985. The ten years from 1985 to 1995 are then dealt with in much detail, including eyewitness accounts from myself and many others, numerous photos, and an analysis of the morphological changes caused by the eruptive activity. Activity after 1995 is described in a more synthetic manner on another page.
The final part of the Stromboli section talks about volcanic hazards, an aspect of studies on the volcano which is receiving increasing attention due to the growing number of visitors to the island, and following studies on violent eruptions in the not-too-distant past. This also includes a discussion of the way tourism is handled at the volcano in the light of numerous episodes of strong explosive activity in the past few years. The interested visitor will finally be guided to further reading and a selection of web sites about Stromboli.
Extensive cross-links to Stromboli On-line are provided throughout these pages. To return to these pages, use the "Back" button of your web browser.