This is early information and it might be wrong! Eruption might not be taking place and this might be a trick of magma movement underground. It is hard to be sure in this case until a visual confirmation is in place.
It appears that an eruption is about to start or has started in Bárðarbunga volcano. The harmonic tremor is going trough the roof at this moment.
It is unclear what is going on at this moment. Nothing has been confirmed yet when this text is written. This might not be an eruption at this point in time, but that might change without warning at any time.