Vesuvius: Shaky Real Estate

I will write later about the city of Pompeii. In its story you will learn that Mt. Vesuvius is the bad guy. Sure Strabone, the Roman geographer, declared it extinct just a few of decades before it blew its top, but as we shall see, the Mountain was just faking sleep as it has so many times in its violent history.

The bus to the hiking station on Mt. Vesuvius stopped ¾ of the way up the mountain for a “bathroom” break at a tourist snack shack. That means that the bus company had an agreement with the shop owner to bring in loads of tourists to buy junk. There, a kindly elderly man named Andrea De Gregorio told us his story of Mt. Vesuvius. He hails from Torre De Greco on the southwestern slope of Vesuvius. His town has been buried in lava flows every century since a 1631 eruption. Four times destroyed! If I were the city planner I think I’d look into a new neighborhood. And given Vesuvius’ history of eruptions I would consider moving from the area all together. For Andrea, it’s been his livelihood.

The first recorded eruption is that of Pompeii/Herculaneum fame in AD 79. By studying the geology of the area, we now know that eruptions have been going on for the past 17,000 years, but Pliny the Younger was the first to actually write about the destructive forces in Pompeii back in AD 79. In the first phase of the eruption, ash, pumice and rocks were blown more than 10 ½ miles into the atmosphere. Eventually the pressure of explosive gasses subsided and this cloud of pyroclastic materials came raining down on the city of Pompeii killing anyone who hadn’t evacuated and burying the city with a thick, preserving blanket of ash. Large amounts of water also escaped from chambers in the mountain and raced down its slopes. The water gathered fine ash on its journey, creating a “lahar” (mud flow) that buried the city of Herculaneum. Because Herculaneum was spared most of the effects of the burning ash (because it was buried in cooler volcanic mud) it still contains some of its wooden structures and supports.

Based upon frescoes found in the homes of Pompeii and Herculaneum we know that the slopes of Vesuvius were covered in vineyards. Pompeian wines were well revered and shipped all around the Roman Empire. It turns out that soil with high levels of volcanic ash is perfect for growing grapes for wine. Santorini is another great example of this. Every bit of vegetation on the mountain was burned in the eruption’s hurricane force winds of scorching gasses at the end of the three days of activity. Locals who escaped the ash and lahars were justifiably reluctant to move back into the area.

Not much was written concerning the numerous eruptions that occurred between AD 79 and 1631. People, at least educated historians and writers, must have kept their distance! While the Pompeii eruption was most noted by Pliny for its ash fallout, later eruptions were noted for their lava flows and changes to the terrain in the area. This is most likely due to a more scientific approach to vulcanology rather than a major difference in how the mountain reacts to its bad gas and explosive eruptions. Pliny was writing a letter and may not have been as thorough in his observations as later scientist. The coastline has been shifted and elevated due to the incredible strength of the gasses that bulge the mountain and its slopes. The caldera and cinder cone have risen, fallen, expanded and shrank several times. The summit shrank almost 500 feet in the 38 years between eruptions in 1906 and 1944. Huge valleys with rivers of cooled lava exist where there was once a mountain slope. There have been at least ten major eruptions since 1631 and numerous small eruptions. There seems to always be some kind of activity on the mountain whether it is a destructive eruption or a quiet release of gas and steam from vents around the caldera.

The mountain now rests quietly in a quiescent stage. Farms, small towns and homes cover its lower slopes. Pine forests fill the sections midway up the mountain. The summit is alive with wildflowers and lichen taking hold where they can among the rocks and cinders. It’s an easy hike with spectacular views of the sea and countryside surrounding the sleeping giant of Mt. Vesuvius.

Mt. Vesuvius

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