Comet 67P jets – where are the fissures?

comet 67p jets fissures cracks where are theyComet 67P's surprising jets (they started early and are so numerous and powerful) were mainly concentrated around the neck region.

But in latest close up photos of the neck region that connects the two lobes there are no fissures or cracks. In fact as shown in this photograph by the Rosetta spacecraft this part of the neck region is amazingly smooth and looks to be made of dusty and rocky asteroid/comet regolith.

If the jets are sublimating ice beneath the surface of this now icy dirtball then where do they come out from?

Where are the cracks and fissures or holes on the surface?
comet 67 p  neck fissure cracks no evidence

In this orientation the large lobe is to the left and the small lobe to the right. The top right frame offers a particularly stunning view onto Hapi, the comet’s ‘neck’ region that is littered with boulders. This view also provides a good look at the many interesting, curved markings visible on the smooth surface.
CometWatch 28 March – 14 km flyby

Or could Comet 67P be an active asteroid and the jets are electrochemical processes? The comets electrical potential difference reacting to the suns electrically charged plasma (solar wind)?

Update 20/4/2015 - mystery night side jet!

comet 67p jets  night side dark side mysteryThere has been a mysterious large jet caught on camera being emitted from the dark side or night side of comet 67p.

this jet looks like it’s on the night-side of the nucleus, which is very intriguing, and the easiest explanation is that there is a little cliff standing out, which is just being illuminated by the Sun but is not seen by the spacecraft.

Comet 67P jets sublimation mechanism mechanic water puzzles“If that’s the case, then we just have to have normal warming activity. If that’s not the case, we have to find another mechanism.”

It is the sunlit regions of the comet that should be most active, not the dark zones.
Rosetta's comet throws out big jet

Update 06/05/2015 - how are there multi directional jets?

comet 67p jets multiple directionsHow do you get such amazing and distinct multi directional jets from these supposed fissures on comet 67P?

With the speed of the comet, its rotation, the solar wind, how are the sublimating ice/water/gas/particles being pushed in all these different directions? Especially since the comet is not that close to the Sun yet?

Perhaps even more captivating is the intricate pattern of activity streaming in all directions from both the small and the large lobe. While many distinct bands of dust extend towards the edge of the field of view, more diffuse regions of activity can be made out close to the nucleus.
CometWatch 26 April