​On the 30th of August 2017 an explosion occurred in Caldeira do Asmodeu fumarole located in the Furnas Village fumarolic field, São Miguel Island. Local inhabitants reported that the turbidity of the water increased before the explosion and all the water disappeared immediately after the event. Subsequently, the water appeared with a muddy aspect. Sampling of the gases released from a close fumarole was done the following day and one week after the explosion. Chemical analyses included gas chromatography for the gases in the headspace of the bottles and titration for those in the alkaline solution. Results obtained were compared with data gathered since 2015 and some ratios were applied to the gas compositions of the fumaroles before and after the explosion. The results obtained did not show significant differences and contributed to confirm that the phenomena should be quite superficial, thus not related with deep changes on the system.