The green star is the magnitude 3,4 earthquake between Bárðarbunga and Grímsfjall volcano.
This earthquake suggests that an complication is on the way. The question here is if an interaction between Bárðarbunga volcano and Grímsfjall volcano is on the way. Since both volcanoes are preparing for an eruption. All that I get from my models (in my mind, since I don’t have the computer power or the skills to make them PC friendly at the moment) is confusion. At worst a magma dyke from either Bárðarbunga volcano might enter Grímsfjall volcano or an dyke might come from Grímsfjall and enter Bárðarbunga volcano (hint: A result of either of such event is rather catastrophic eruption, even if just for a short time). What can also happen is nothing, just earthquakes and nothing more. However, increase in the earthquake activity at this location suggests that no such luck is on the way. When and if such event happens is impossible to know, what can be done is to keep monitoring, day and night. This is going to happen the when and the way it wants to happen, all that can be done as humans is to wait and see.