VESUVIUS RIGHTLY holds a place at the top of a tally of the world’s deadliest volcanoes because of the sheer number of people now living in very close proximity. Following the deadly eruption of 1631, Vesuvius was active almost continuously, right up until the wartime eruption of 1944. Since then, however, the volcano has been quiet.
While Vesuvius has shown little sign of activity for close to 70 years, the same cannot be said of the inhabitants of the region. Rapid post-war construction, much of it unregulated or illegal, has resulted in a huge increase in the numbers of people living on its flanks.
The population of the highest-risk ‘zona rossa’ (red zone) has exploded to more than 600,000, all of whom will be in grave danger when the volcano once again springs to life. In a belated attempt to tackle this problem, the civil authorities are now offering financial incentives to try and encourage people to move to safer locations, but this has had little effect and is unlikely to make much of a dent in the numbers at risk.
Meanwhile, the volcano has shown little sign of a return to active life. While this is broadly regarded as a good thing, there is also some concern that the longer the volcano slumbers, the more violent the blast will be that heralds its awakening.
When Vesuvius does decide to perk up, however, at least we will know at once. The volcano is one of the most closely jj monitored on the planet and its slopes are l littered with sensors designed to pick up the slightest and most fleeting signal that Vesuvius is stirring.
Seismometers listen out for the tiny tremors that might indicate magma is on the move, while a network of GPS stations hunts for any ground-swelling caused by new magma making its way into the volcano’s interior.
A swarm of earthquakes beneath the volcano in 1999 concentrated the minds of monitoring scientists and civil authorities alike, but the volcano soon returned to its slumber. Now all they can do is watch, wait, and plan.
The problem is, what to plan for? The evacuation strategy of Italy’s Department of Civil Protection assumes an eruption 10 times smaller than that of 79AD and up to a couple of weeks of prior warning in order to get people out. Others, however, think that this is too optimistic and a recipe for disaster.
THE VOLCANO WILL erupt again, but when this will happen and how big the eruption will be is anyone’s guess. While there is a great deal of discussion and debate within the Italian volcanological community about the scale of the next blast, the betting is that it will be similar to that of 163L
This was 10 times smaller than the 79AD explosion, but a higher population density meant that the death toll was higher, with some 4,000 people trapped in pyroclastic surges. With many more now living around the volcano, a repeat of 1631 could see a far higher death toll. It’s a fear for those who have little confidence that the current evacuation plan will work effectively.
Furthermore, 1631 is far from the worst-case scenario that some volcanologists feel should form the basis of the evacuation plan. This notion has gained ground over the last year or so, following the identification of a possible active magma reservoir 8-10km beneath the surface, which appears big enough to feed eruptions on the scale of 79AD.
Even scarier, the discovery that a titanic Bronze Age eruption 3,800 years ago sent pyroclastic flows across the entire area of Naples, has taken the worst-case scenario to a whole new level. On this basis, some think that once Vesuvius shows signs of awakening, everyone within 20km of the volcano should be evacuated; a number that would reach into the millions.