Edit: False alarm. the VAAC of Tokyo mis-represented the ash plume and attributed it to the wrong volcano.
There is not a ton of information currently, but the Tokyo VAAC (Volcanic Ash Advisory Center) has reported ash emissions from the volcano Maly Semyachik in Russia.
Report can be found at: http://ds.data.jma.go.jp/svd/vaac/data/TextData/2017/20170707_30014000_0001_Text.html
Now, there are a lot of volcanoes that are currently erupting that I do not regularly report on, and a lot of volcanoes that start new eruptions that I do not write posts about. Maly Semyachik may be a little bit more interesting however, since it has not erupted since 1952, and has the ability to create larger eruptions as well as small effusive eruptions. Gauging what is going on here is difficult to say at this point until more information comes out.
I would speculate that this could potentially be a throat clearing event, where the volcano is pushing out old ash and cooled rock from the vent so that fresh magma can make its way to the surface via an eruption. Since there isn’t much detail in the VAAC report about the size of the plume, it’s quite likely that this was a very small event. With that said, small events like this can be a precursor to larger magmatic eruptions at times. Only time will tell with this volcano.
Maly Semyachik Background
Maly Semyachik is not a well known volcano, similar to most of the volcanoes in Kamchatka. It is quite remote, sitting in eastern Kamchatka well north of the city Petropavlovsk-Kamchatsky. As such, there likely would not be many eyewitness accounts to a new eruption starting unless there was a lot of advanced warning as to when a new eruption may occur.
Kamchatka’s North-Eastern volcanic zone is likely one of the more active regions in the world for volcanism when comparing the size of the region to the volume of eruptive activity that has occurred in the geological past. While this is an extremely active region, there haven’t been any notable eruptions in the recent historical past, mostly just small sized eruptions and throat clearing events.
The region does however host a lot of very large calderas, and some of the volcanoes have multiple nested calderas, so we know that the potential is there for larger eruptive events. Nearby Karymsky had a notable caldera forming eruption early in the Holocene period, which promptly sprouted the beautiful somma volcano from the caldera left from the eruption.
Recent Eruptive History
The eruptive history with Maly Semyachik has recently been small eruptions near the VEI-2 range according to the Global Volcanism Program. There was a VEI-4 blast around 1500 AD, and prior to that, the eruptive activity is a lot more murky with a lot of verified eruptive events, but not much detail on the size or explosivity of each event.