On the 3-October-2017 there was an increase in earthquake activity in Katla volcano as I wrote about here. This activity was deeper than suspected as during the night there was an small harmonic spike as was mentioned in this comment here.
Today (08-October-2017) there was a news on Rúv about sulphur smell being detected and higher conductivity in Múlakvísl glacier river at the same time. The main idea is that one of the twenty cauldrons was emptying it self of hydrothermal melt water that builds up in them, resulting both in the increase conductivity and the harmonic tremor being detected as the cauldron empted it self. This does result in a minor glacier flood in Múlakvísl glacier river. I don’t know for sure what the case is here, but this type of activity has been happening consistently for the past few months in Katla volcano. Conductivity remains rather high in Múlakvísl glacier river according to latests automatic readings on Icelandic Met Office website.
Icelandic news on this
Brennisteinslykt á Mýrdalssandi (rúv.is)