Down, down, down, I went. Deeper and deeper into the most magnificent and terrifying cave that I've ever seen. At the 101-meter point in this cold, subterranean world, I got to thinking about the circles of Dante's Inferno; I also briefly wondered if there was an elevator nearby. (Alas, none to be found).
This summer, I learned so much during the one-hour descent and ascent of La Grotta Gigante. But one of the most interesting things for me was that there are two geodetic pendulums hidden in white vertical tubes (seen in the photo) that are fixed to the rock at the bottom of this cave. To this day these instruments are used to study movements of the Earth's crust. What's fascinating is that the discovery of the cave in 1840 by an explorer who was looking for fresh water, led to the development of this tectonic tool for detecting earthquakes. The "tiltmeters" in this cave are the only existing instruments to have recorded four out of the five major earthquakes in the past 50 years: Chile (1960 and 2010), Sumatra-Andaman Islands (2004), and Japan (2011).
I also learned that my skinny legs can still climb 500 steps. |