Topic: Stacks - Pilot Point
Pilot Point for the purposes of my project, begins at the cave which is a short distance north of the Pilot Point Arch. Pilot Point Arch fronts onto the Tongaporutu River estuary. Thus, Rapanui ends at the cave and Pilot Point starts there, even though physically they occupy the same real estate (one runs seamlessly into the other.) Pilot Point is on the northern side of the Tongaporutu River.
There is only one rock stack at Pilot Point and I have nicknamed it PAT’S STACK. This new rock stack was created during a full cliff face collapse that occurred on 20 July 2008 during Super-Storm One, part of a Super-Storm Event.
This new stack had originally been a substantial arch. The cave site to which the arch belonged was where the Tongaporutu Project began. Naming it after me is not an ego thing, rather, its because the cave is the project’s birth place. Also, because I am the first person to have seen it since its creation. It will be interesting to see how long it lives.
SUPER STORM EVENT. Super-Storm One. Pat’s Stack was born in the debris of a massive, full cliff face collapse that according to the O’Sullivans (who live on the farm above), had occurred within the past 24 hours. There is a lot of loose material on top and the stack itself has a large debris pile to its rear and northern side. It is heavily fractured.
At the cave, Pat’s Stack had lost more of its top material. A lot of rocks and boulders remained at the debris field site, but the soil had all gone. Standing in a similar spot to where the Tongaporutu project began, this time around, I felt wretched with the flu.
31.8.2008 PHO2011-1306, 1314-1315
More of the debris field had dissipated and Pat’s Stack was now clean of material. The top had stabilized, at least temporarily. That is, the loose stuff on top had sorted itself out for the moment. This rock stack is 15-20 away from the parent cliff.
CLIFF SEQUENCING. Pat’s Stack appears reduced in height. As such, it looks like it will be relatively short-lived, this location being rather volatile. The photo is a location shot, not a close-up.
I took a photo from the cliff top looking down on the cave area and Pat’s Stack. It is well defined and the top knot of close clustered rocks appear stable for the present.
3.6.2009 PHO2011-1603, 1605
My rock stack still appears to be toughing it out. Of the rock debris from the July 08 collapse, a lot had migrated quite a way out to sea. A number of the largest boulders were still there, anchored in a high sand level.
The weather was dullsville with fog and low cloud. Due to time constraints I was unable to access the cave. However, I did get far enough out to seaward to confirm that my rock stack is still there.
Pat’s Stack is still there, but it doesn’t look very permanent. It appears to be a bit lower with some loose rocks on top of it. It’s like it is being shrunk from the top down. Specifically, it is being smashed at the base by direct wave action, causing the top to wobble. Additionally, secondary shock-waves generated by the waves are shaking the top ‘loose’, causing it to fracture. This resulting in a loose rock debris field atop the stack. Further, resonance bounce could also add its six pennies worth. I could be wrong of course.
Pat’s Stack is still hanging in there, but it has a lot of loose rocks and material on its top. There also appears to be a top to bottom open crack on the seaward side, but this could just be a light/shadow illusion. It also appears to be shrinking in height, but this too could also be an illusion. Or, it could be that the stack is being destroyed from the top down. Specifically, it is being smashed by waves at the bottom and the ‘wobble effect’ is loosening material at the top. I took a landscape photo to show Pat’s Stack and the cliff environment where it is located.