2 0 1 1 ▁to ▁February ▁ 2 0 1 2 , ▁the ▁sum mit ▁cr aters ▁of ▁Et na ▁were ▁the ▁site ▁of ▁inten se ▁activity . ▁Fre quent ▁er u ptions ▁and ▁ash ▁columns ▁forced ▁the ▁authorities ▁to ▁shut ▁down ▁the ▁Cat ania ▁air port ▁on ▁several ▁occasions . ▁▁ ▁The ▁July ▁ 2 0 1 1 ▁episode ▁also ▁end anger ed ▁the ▁S ap ienza ▁Ref uge , ▁the ▁main ▁tour ist ▁hub ▁on ▁the ▁vol cano , ▁but ▁the ▁la va ▁flow ▁was ▁successfully ▁di vert ed . ▁In ▁ 2 0 1 4 , ▁a ▁fl ank ▁er u ption ▁started ▁involving ▁la va ▁flows ▁and ▁st rom bol ian ▁er u ptions . ▁This ▁was ▁the ▁first ▁fl ank ▁er u ption ▁since ▁ 2 0 0 8 – 0 9 ▁▁ ▁On ▁ 3 ▁December ▁ 2 0 1 5 , ▁an ▁er u ption ▁occurred ▁which ▁clim ax ed ▁between ▁ 0 3 : 2 0 ▁and ▁ 0 4 : 1 0 ▁local ▁time . ▁The ▁Vor agine ▁cr ater ▁exhib ited ▁a ▁la va ▁f ount ain ▁which ▁reached ▁ ▁in ▁height , ▁with ▁an ▁ash ▁pl ume ▁which ▁reached ▁ ▁in ▁height . ▁The ▁activity ▁continued ▁on ▁the ▁following ▁days , ▁with ▁an ▁ash ▁pl ume ▁that ▁reached ▁ ▁in ▁height ▁that ▁forced ▁Cat ania ▁air port ▁to ▁shut ▁down ▁for ▁a ▁few ▁hours . ▁Vol can ic ▁gas ▁em issions ▁from ▁this ▁vol cano ▁are ▁measured ▁by ▁a ▁Multi - Component