I’m taking you back to the bay of Naples again (not many more times now, promise)! 😉
Most people have heard of Vesuvius and the havoc its eruptions have wrought. But fewer people seem to have heard of the much larger volcano that underlies the area north west of Naples. Known as the Campi Flegrei or Phlegrean Fields (fields of fire), this volcanic complex forms an area around eight miles wide, much of which is under the sea. There isn’t a peak in the style of Vesuvius, although an eruption threw up Europe’s newest mountain – Monte Nuove – in 1538.
Instead, this is a caldera, formed when the chamber of magma lying beneath a volcano is depleted by an eruption. The chamber is no longer able to support the weight of the ground above, and it collapses in on itself. Around 37,000 years ago there was a massive eruption here and the land collapsed, leaving a caldera on which several towns and much of Naples is built. As the magma replenishes and the pressure builds, the topography of the land changes again and subsequent eruptions have left new calderas. Another huge eruption around 12,000 years ago formed the caldera of the Campi Flegrei, and volcanic activity since has left a number of cones and craters, some of which fill with water – Lago d’Averno with its sulphurous fumes was described by Virgil as the entrance to the underworld, and the volcanic fumes were what reputedly gave the famous Sybil of nearby Cuma her prophetic abilities.
What’s left now is a very interesting landscape which we intended to spend a day exploring. We were so entranced by our first destination, though, that we ended up spending most of the day there. The Solfatara is the most active volcano in the Campi Flegrei, formed around 4,000 years ago. It hasn’t erupted since the 1198, and although it is classed as dormant now, there is lots of residual activity. The crater is a bleached moonscape of white rock with bubbling mud in the middle and steam hissing from fumaroles. The rim of the crater is carpeted with vegetation and the town of Pozzuoli – it’s a little bizarre to see houses so close while you stand on hot ground with steam rising all around you. I’ll tell you about Pozzuoli in the next post.
Not being keen on strong smells, I didn’t know how I’d cope with the sulphurous gases that characterise the Solfatara. In fact the smell wasn’t that strong, and after a while I rather enjoyed it. Steam seems to exit from every crack in the rock, leaving lurid yellow sulfur crystals around the holes. The high drama comes from the Bocca Grande (big mouth) though; fumaroles where 160 C sulphurous gasses hiss out of the ground from the cooling magma chamber below. In typical Italian fashion, the cooler fumarole is fenced off while the hotter two are not. This allows you to risk a scalding to stand in the midst of the swirling steam. and look at the rocks piled on the top of the vents (so that they can be sold as souvenirs). These become encrusted with mineral deposits from the gases, most startlingly the arsenic sulphide realgar which is an incredibly vivid purplish red. It was a really intoxicating experience, which I don’t think photos can really convey.
We had the place almost to ourselves for a lot of the time, although there was an Italian family attempting to cook eggs in the one of the Bocca Grande vents (they managed to do one, but the others exploded or were too hot to retrieve). A tour guide showed off his party trick of waving a lighted torch of newspaper around, which causes the steam to increase hugely – apparently the gases condense around the smoke particles. We saw another guide demonstrating to some British teenagers how if they dig a stick into the ground, it will immediately begin to release steam. The ground is unnervingly hollow and hot to touch. Don’t do as I did and sit down on a convenient rock when feeling a bit tired – I’ve never got up so quickly in my life. 😀
Despite the wildly sensationalist tone at the beginning, the article here has some interesting information about the volcano and how the Campi Flegrei and Vesuvio are monitored. There’s been rather a controversy over the last couple of years about the plan to drill down into the caldera and insert probes to more comprehensively monitor the volcano’s activity.
Here are some pictures, and if you scroll down, a couple of videos too.