The evening news on Rúv did show video of the fissure in Thingvellir. The fissure it self appears to be a extension of the current fissure named Almannagjá. That fissure is old. But this formation appears to be fresh. But it hard to know for sure how long it is since it was created. But the road has been there since the late 19th century. One of the ideas why this happened is that there is a connection with this fissure creation and the earthquakes in the SISZ in the year 2000 and 2008. But that however is unproven idea at this point.
Other then this I have not seen or got a lot of information about this fissure.
Here is a video of this fissure in the Rúv news at 19:00 UTC.
More information on Thingvellir and it’s geology.
Geology and tectonics of Þingvellir
According to a news on Rúv. A new fissure has opened in south part of Almannagjá. It is not clear when this fissure started to form, but it looks to have formed in rather recent time (years?). But this fissure was discovered after a snow and frost started to thaw out of the ground in the last few weeks. This new fissure is about 10 to 14 meters deep and is under the middle of the walking path that is in this area. It has now been closed for safety reasons. Tourists and people how are travelling this area of Thingvellir are asked to respect the travel ban in this area. But this is a deep fissure and it is unmarked and dangerous.
This area is in part of the Hengill volcano fissure swarm. But it on the north-east edge of the end of that fissure swarm that extends from Hengill volcano.
News about this fissure formation. With picture. Use Google Translate with care. After all, it doesn’t understand Icelandic.
Djúp sprunga fannst undir göngustíg (Rúv, Icelandic)
Djúp sprunga myndast í Almannagjá (DV, Icelandic)
Updated at 15:57 CEST on the 31. March 2011. New newslink added.