Not only does the volcano provide an affluent agricultural base for the area, but also a favourable site structure with, “two roughly semi-circular depressions opening to the sea (Lobley c.1889: 49). The popularity of the immediate vicinity of Vesuvius is emphasised in the neighbouring city of Naples, the most densely populated city in Europe, with over a million inhabitants crowded into an area of little more than four square miles (Lobley c.1889: 48).
A further reason for the popularity of the bay is that Vesuvius has been in respose since 1944 and many people have deduced from this that the volcano is extinct. An unexpected renewal in activity would reap hazardous effects on the area, causing inevitable economic failure due to the dependency on the land, taking several years to even begin to return to the customary standard. After the eruption of 1944, cultivation recommenced between 1945 and 1946, and the humus was built up again after a few years (Sheets and Grayson 1979: 615).
Despite all the potential dangers, and the lengthy history of past destructions, settlements have continued to grow uncontrollably at the base of Vesuvius without paying any attention to the volcanic threats (Tazieff and Sabroux 1983: 161). Principally, there is the exposure to a variety of volcanic hazards including lava flows and the catastrophic Plinian explosions with their series of pyroclastic falls, surge, flows and lahars. The regions vulnerability is worsened by the fact that Vesuvius is not the only volcano threatening the area; on the adjacent side of Naples, the caldera of Campi Flegrei has been displaying signs of unrest in the last three decades. “To complete this equation of geologic hazards, the area forms the nucleus of a much vaster zone that is seismically vulnerable; its most disastrous earthquake, on 23rd November 1980, killed more than 3,000 people (Richter 1986: 1)
When the prospective risks are this severe, forecasting volcanic activity is extremely important. Timely evacuations may save lives, but they won’t avoid sizeable economic damage to densely occupied agricultural areas, like the region surrounding Vesuvius. “In order to keep the economic damage as low as possible, it is necessary to plan the use of volcanic territory correctly (Tazieff and Sabroux 1983: 149).” Regardless of the unruly settlement layout encompassing the volcano, future sensible development can be encouraged with the identification of areas of high volcanic risk. The initial step is to assess volcanic risk by constructing a map where sectors of different degrees of hazard, in terms of intensity and probability, are identified. From this, it becomes easier to plan the positioning of buildings of significant importance, for example hospitals, and others that are difficult to evacuate and are of high value (Tazieff and Sabroux 1983: 149).
Because of it’s dense inhabitancy and long history of devastation, Mount Vesuvius was considered a high priority in terms of assessment, so in 1976, the Italian Geodynamic Project was launched (Tazieff and Sabroux 1983: 149).
The initial research involved an investigation at Vesuvius of eruption prediction by examining the activity and history of the volcano; it can be divided into eight cycles. Professor Palmieri, the director of the Vesuvian Volcano Observatory first noted this in 1872, and announced that the, “eruptions of Vesuvius follow a cyclic pattern which makes it possible to predict, at least to some extent, the pattern of activity of an eruption. The recognition of the cyclic behaviour of Vesuvius stimulated other workers to try to establish patterns for other volcanoes, and the results of their efforts proved to be an important step in the advancement of volcanology (Bullard 1962: 130).”
Each cycle began with a Plinian eruption, marking several centuries of activity. The last phase lasted between 1631 and 1944 that included relentless lava flows and inconsequential explosions. Nonetheless, these Plinian eruptions are extremely consequential, with their high explosivity, high eruption rates and large volumes of erupted magma, they are considered the most troublesome event related with Vesuvius. The inevitable pyroclastic falls, surges and flows after a Plinian eruption were all seriously considered, and a preliminary hazard map was drawn up. The damage would be absolute if one was to occur in the present day, which is why it could be considered lucky that the only activity that took place throughout the last cycle was of the Strombolian kind, which featured lava flows and eruptive fractures. A hazard map was drawn up stressing the most dangerous areas situated around the central cone. (Tazieff and Sabroux 1983: 150-161) Despite these precautions, a lava flow on the slopes of Vesuvius is pretty deadly from the aspect that the area is so densely populated; the town Torre Annunziata has been destroyed four times, most recently in 1906, yet has been rebuilt after each occasion (Bullard 1962: 63).
Hazard zoning maps are valuable for indicating logical land uses, and to civil-defence officials for calculating future eruptions, but it doesn’t make the job of monitoring by volcanologists and public officials any easier (Tazieff and Sabroux 1983: 149). Vesuvius Observatory, built between 1841 and 1845, aids this task. Some of the top volcanologists in Italy work at the Observatory, but despite recent key technological advances in the last two decades, the aptitude to predict volcanic activity is still relatively elusive (Mayell 2002:1). The monitoring system is composed of geochemical and geophysical networks. “The geochemical networks control seismic activity, the ground deformations and the gravimetric and magnetic field variations. The geochemical networks monitor the variations in the composition and temperature of the fumaroles and aquifer gas emissions which could be related to the presence of magmatic fluids (Petrosino 2000:1).”
Monitoring is extremely important, but it’s not always practical or affordable, yet so is the evacuation of large numbers of people, particularly in the midst of indeterminate volcanic threats. Above all, it is extremely costly and complex, especially when there are 3.75 million people living within 30 kilometres of Vesuvius’ summit. (Mayell 2002:1).
Despite the implications of evacuation, there is no other alternative when land-use patterns are long established, and the prospect of moving people permanently is simply not an option. The only feasible solution is to maintain an efficient monitoring system to detect any volcanic activity, and uphold public support, especially when the socio-economic consequences of an evacuation are so big. The re-housing and feeding of the evacuees, along with the inevitable problems of looting from the vacant buildings and the loss of earnings from the frozen trade makes the prospect of accurate volcano prediction particularly important, especially when the consequences of failing to predict could be so catastrophic. (Mayell 2002:1)
References
Bullard F M (1962), “Volcanoes; In History, In Theory, In Eruption,” Thomas Nelson and Sons Ltd, Edinburgh
Sheets P D and Grayson D K (1979), “Volcanic Activity and Human Ecology,” Academic Press, London
Tazieff H and Saboux J C (1983), “Forecasting Volcanic Events,” Elsevier Science Publishers, Amsterdam
Lobley J L (1889), “Mount Vesuvius,” Roper Drowley, London
Richter (1986), “Vesuvio [online],” [Accessed 18th November 2002], Available from World Wide Web
Mayell H (2002), “Volcanoes Loom as Sleeping Threat for Millions [online],” [Accessed 18th November 2002], Available from World Wide Web
Petrosino A (2000), “Vesuvius Observatory [online],” [Accessed 22nd November 2002], Available from World Wide Web
Emily Beedham
Student Number: 020178417
Mount Vesuvius; an assessment of the present day situation
Word Count: 1458