Last year, an inquisitive team set upon an expedition to explore Mt. Etna in Italy. This was the eighth annual expedition of its type with a mission to study “…the most interesting volcano in the world.”

The expedition is shared in detail in XYZ, the French Association of Surveying’s journal. Written from four perspectives – from the editor in chief, two students and a land surveyor – it is the land surveyor’s perspective that brings, for us, the most interesting story.

More than 30 years ago, observations were made of Mt. Etna’s movement and lava flow, the most active volcano in Europe, using the Global Positioning System (GPS). These historical measurements provided a benchmark for modeling and understanding the volcano’s movements. The original points of observation, now covered by material from eruptions, provides one of the most difficult challenges of the expedition – finding where those points lie today.

The group of students and experts worked with Geotopo, a Trimble distributor, to collect the equipment needed to find these points of observation, as well as to take new measurements. Using Trimble’s Alloy GNSS reference receiver and the Trimble R10 GNSS system, both enabled with Trimble’s RTX™ CenterPoint® correction services, they confirmed the original points of measurement had moved three meters east beneath 15 centimeters of volcanic ash! Previous GPS coordinates combined with real-time points of reference from the receivers made this determination possible.

In addition to relocating and remeasuring reference point displacement, the expedition set out to measure the depth of lava flows from Mt. Etna. Previous expeditions had positioned points of measurement, but as the movement points had been covered, so had the lava points by subsequent lava flows. Locating these points to within a few tenths of a centimeter, the Trimble Alloy GNSS reference receiver made it possible to obtain the GNSS coordinates and determine the thickness of the lava flow. A depth of approximately 13 meters was found in some locations, while it was more than 40 meters deep closer to the crater.

Read about the editor and student perspectives, along with the full description from Geotopo in this article from XYZ. Enjoy the Sicilian sunsets and sunrises as described by group throughout their exploration of Mt. Etna! As a bonus, this video produced by Geotopo shares a visual perspective of the journey (in French).

For more information on Trimble's Alloy GNSS reference receiver and related products, visit here.

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