According to a Met Office natural disasters specialist, the new opening appears to be in roughly the same area where a sag in the landscape was noticed yesterday by search & rescue workers. That area was 150 metres long and around 450 metres north-east of the original eruption in Geldingadalir.
The eruption site was due to re-open to visitors this morning at 06.00, but the opening was delayed. It is not yet known when visitors will be allowed back.
The opening of the new fissure was captured live and can be seen above in real-time and below in time-lapse.