Virtual Volcano Vacation #33 WINNER! – Campi Flegrei

The eruption of Monte Nuovo illustration - Plate VI from Sir William Hamilton’s Campi Phlegraei: Observations on the Volcanos of the Two Sicilies (1776) - Image originally found at The Volcanology Blog

The eruption of Monte Nuovo illustration – Plate VI from Sir William Hamilton’s Campi Phlegraei: Observations on the Volcanos of the Two Sicilies (1776) – Image originally found at The Volcanology Blog

For this week’s virtual volcano vacation, I thought about celebrating Vesuvius Day by “dropping in” on one of the world’s most famous volcanoes for a second time, but I have a feeling that it would be the first place everybody would look. So I figured I would hide right next door to the first place everybody would look..because that would be the last place anybody would look….and it seems to have almost worked.

I never really gave Campi Flegrei much thought before, except as a bubbling oddity that occasionally gets called a “supervolcano” by the likes of DailyMail and IFLScience. But the idea of an urban volcano seemed an appealing gimmick for a virtual vacation and I began nozin’ aroun’ for interesting facts and trivia. Now I’m thinking that “awesomevolcano” needs to become “a thing”.

Map of the main craters of Campi Flegrei - Image originally from Wikipedia

Map of the main craters of Campi Flegrei – Image originally from Wikipedia

But where to begin? With 24 craters and volcanic edifices to choose from, to pick just one seemed a bit like getting Neapolitan ice cream and only eating the chocolate. So I began my trek at Monte Nuovo. This small green cinder cone is touted as Europe’s youngest mountain, having erupted itself in the year 1538…from 29 September to 6 October to be precise. The eruption was preceded by violent earthquakes and changes in land elevation…the sort of thing that “supervolcanoes” do…at least according to “supervolcanologists“. A much more recent period of quakes and land deformation in the late 20th century had some scientists worried Monte Nuovo was about to reawaken, but if there is one thing that can be predicted about volcanoes, it is that they will be unpredictable.

Monte Nuovo with Lago di Averno in the foreground - Original image from Liniziativa.net

Monte Nuovo with Lago di Averno in the foreground – Original image from Liniziativa.net

But the aptly named “new mountain” is just the tip of the proverbial iceberg. It is just one small part of a 13 kilometre wide volcanic caldera, much of which now lies underwater in the Gulf of Pozzuoli west of Naples. The caldera was formed by two cataclysmic events. The first, called the Campanian Ignimbrites, began with a volcanic column at least 40 kilometres high which resulted in the creation of a caldera, followed by a second eruptive column (much like what took place at Crater Lake) which produced pyroclastic flows that deposited ignimbrites (layers of ash, tuff and lapilli) in a circle radiating at least 1,500 kilometres from the eruption’s origin. Then, about 17,000 years ago, a second large eruption called the Neapolitan Yellow Tuff created a smaller caldera within the original caldera and deposited its distinguishing yellow rock around the area. The caldera’s most geologically-recent eruptions (from 15,000 BCE forward) have occurred at multiple vents and produced a white ejecta called Pozzolana. This material is abundant in most of the volcanoes within the Phlegraean Fields and is the key ingredient in Roman cement.

Exposed volcanic deposits at Procida, including welded pyroclasts, lithic breccias, olivine rich magma, ash and pumice - Original image from NapoliUnplugged.com

Exposed volcanic deposits at Procida, including welded pyroclasts, lithic breccias, olivine rich magma, ash and pumice – Original image from NapoliUnplugged.com

Deep below the caldera lies a large body of magma that has throughout the area’s history changed volume, causing the land to very slowly rise and fall, a phenomenon called bradyseism. This rising and falling is made evident by the presence of tiny boreholes left by marine mollusks upon the three standing columns of the ruins of the Macellum (marketplace) of Pozzuoli. Also, contemporary hydrothermal springs and fumaroles within the caldera testify to the presence of magma below.

Next I visited an interesting but frustrating tuff cone called (depending on who you ask) Monte Babaro, Monte Gauro, Mount Gaurus, or by the seemingly antiquated moniker, the Campaglione Volcano. The lopsided crater now contains a recreational facility called Carney Park. Named after Admiral Robert B. Carney who served as Chief of Naval Operations during the Eisenhower presidency, the park was originally built by the US Department of Defense and administered by the US Navy under the auspices of Naples’ Navy Support Activity (NSA). The facility includes a golf course, swimming pool, tennis and basketball courts, football and soccer fields, baseball and softball diamonds, tent and cabin camping including a site for Girl Scouts and Boy Scouts, as well as picnic areas and a restaurant. Suffice it to say that you can do just about anything you’ve ever wanted to do inside a volcano at Carney Park…except play with lava, as the volcano is extinct.

A baseball game at Carney Park inside extinct volcano - Original image from Department of Defense Lodging

A baseball game at Carney Park inside extinct volcano – Original image from Department of Defense Lodging

Then I went even further east to Cratere degli Astroni, one of the largest and well defined features of the Campi Flegrei. In ancient Roman times it was known for its hot mineral springs, but during the 16th century when volcanic activity suddenly shifted westward and Monte Nuovo was born, the hydrothermal activity ceased and the crater became a royal hunting preserve for Alfonso I of Aragon, who built a high embankment around the crater rim. Later on, a wall built of volcanic tuff was added to further secure the perimeter. In the early part of the twentieth century, the crater became an unregulated tourist attraction, which had a devastating impact on the unique environment within. Fortunately, in 1987, Astroni crater was declared a Reserve and has since been under the care of the Campanian Institute of the Ministry for the Environment and the World Wildlife Fund/World Wide Fund for Nature. (WWF).

Lake and hills within the Astroni crater - Original image from TripAdvisor.com

Lake and hills within the Astroni crater – Original image from TripAdvisor.com

After that, I turned south and found myself in a steaming, bubbling sulfurous shallow volcanic crater called Solfatara. It is currently the most geologically active part of Campi Flegrei and contains fumaroles and gurgling mud pools. Not surprisingly, “solfataric activity” refers to when a volcanic area emits sulfurous gas and steam. Two large fumaroles can be found near the southern part of the crater. They are called “La Bocca Grande” (the bigmouth) and their emissions have turned the surrounding rocks a coppery golden hue. In the middle of the crater are the Fangaia, mud lakes that boil at temperatures from 170-250 centigrade. The ancient Romans took advantage of the therapeutic properties of the volcanic steam for their baths of the sort of which one ancient example still exists on the western side of the crater. The crater was also said by the ancients to be the home of Vulcan. Though Solfatara might be the center and point of origin of the entire caldera, the crater has not erupted since 1198. Still it is monitored closely for signs of uplift that might indicate rising magma and impending future eruption.

Congratulations Leslie. It took you a little longer but you found me. Leslie picks up eight points for identifying the volcano in general plus three extra for naming three of the four craters.

Image credits:
Postcard #6 (unnamed image of Roman bath) by Panoramio user lakegeneva

 

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