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Explosions at Etna and Stromboli (19-22 December 2010)


xplosion from the Bocca Nuova on 22 December 2010, seen in frames recorded by the thermal video cameras of the Montagnola (EMOT; top), and Nicolosi (ENT; bottom). The emission of hot - though non-incandescent - material is well evident as a thermal anomaly in the images, which also show the subsequent evolution of the ash plume rising a few hundred meters above the summit of Etna, and drifting northeast

After more than one month of relative quiescence at Etna, at 04:46:50 GMT on 22 December 2010, a strong explosion occurred at the western vent of the Bocca Nuova (BN-1). This event generated an ash plume a few meters high, which then moved into a northeasterly direction, causing light ash falls to as far as the town of Linguaglossa. Video recorded by the thermal camera of the Montagnola (EMOT) clearly show the emission of hot material with temperatures exceeding 60° C; a thermal anomaly is also evident in the footage recorded by the thermal camera of Nicolosi (ENT). However, the visible light footage recorded by other INGV monitoring cameras did not show any emission of incandescent material.

The 22 December explosion was probably less powerful than the one on 25 August 2010, but certainly stronger than the numerous subsequent events between late-August and late-October. Smaller emissions of reddish-brown ash continued to occur during the forenoon of 22 December.




Sequence of three explosions at Stromboli on 19 December 2010, recorded by the Pizzo thermal video camera (SPT); the first and second frame show the maximum expansion of the first and strongest explosion; the other two frames show the maximum expansion of the second and third explosion

At Stromboli, on 19 December at 09:56:08 GMT, the vent labeled “S” in the southern part of the crater terrace produced an explosive sequence consisting of three events. The first explosion, which opened the sequence, ejected coarse-grained pyroclastics followed by more fine-grained material, to a height of more than 250 m above the crater terrace. After a few tens of seconds, a second, slightly less intense explosion occurred at 09:56:21. At 09:56:32 the third and last explosion occurred, which was weaker than the earlier two, with a pyroclastic jet reaching a height of 180-200 m. The fine-grained products (ash) of this sequence were dispersed over the W and NE sectors of the island. The thermal monitoring camera of the Vancori (SVT) has allowed to identify the three explosions more clearly than was possible from the Pizzo camera (SPT) footage, where the rapid succesion of the three explosions generated a superposition of the jets ejected by the second and third explosion and the falling material from the preceding events.



The three explosions characterizing the 19 December 2010 explosive sequence at Stromboli, as recorded by the thermal monitoring camera at the Vancori (SVT). Each frame shows the maximum expansion of the respective explosions.