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I cavi a fibre ottiche sono stati usati con successo per misurare le scosse della frana di Brienz (GR). Lo ha annunciato il team di ricerca delI’Istituto federale di ricerca per la foresta, la neve e il paesaggio (WSL) e del Politecnico di Zurigo. I ricercatori hanno testato il metodo durante l’evento culminato, il 16 giugno 2023, con la caduta di circa 1,2 milioni di metri cubi di roccia.
Il grafico raffigura le misure radar (in alto) e le misure sui cavi in fibra ottica sotterranei
Grazie al metodo Distributed Acoustic Sensing (DAS), i ricercatori misurano lungo la fibra interrata le deformazioni in tempo reale e con una precisione di pochi metri. “Le misurazioni hanno superato le nostre aspettative”, afferma il sismologo del WSL Fabian Walter. “Siamo riusciti a rilevare centinaia di piccoli distacchi di roccia prima dell’evento principale”.
Per 45 giorni sono stati inviati impulsi laser attraverso un cavo posato tra Tiefencastel e Filisur. Per filtrare le vibrazioni causate dal traffico è stata usata l’intelligenza artificiale. Resta l’ostacolo dell’enorme quantità di dati (diversi terabyte al giorno) e i costi ancora elevati del filtraggio.
Il reportage da Brienz
Telegiornale 04.07.2023, 20:00
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