Topic: Cliffs - Gibbs' Fishing Point

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GIBBS’ FISHING POINT

The Gibbs’ Fishing Point separates the Four Brothers beach from Beach One.

For my purposes, the Gibbs Fishing Point starts at the cliff I call ‘the Wall’.  (This has Cathedral Cave on its landward side.  Cathedral Cave runs parallel to and is roughly the same length of its host cliff).  A ship’s bow is prominent at the northern end of the Wall.  This cliff is part of a semi-enclosed small bay that is exposed to the north/west but totally protected from the south/west.  The cliff then curves around into a more or less straight line that runs south before turning landwards where it culminates in the northern boundary of Beach One.

The entire cliff section at Gibbs’ Fishing Point, wrap around from north to south in a remarkably smooth ‘wall’.  There is one large rock stack that is located just off the western cliff section that I have called Gull Rock.  Although the entire section has wall-like cliffs, the cliff I actually call ‘The Wall’ is the one that houses Cathedral Cave whose entrance is on the Four Brothers Beach.  On the outer seaward side, opposite Gull Rock and part way down the cliff, is a long, narrow ledge that people fish from.  It is often referred to as either Gibbs’ fishing ledge or Mackenzies fishing ledge.  Interestingly, in rock strata immediately to the rear of the ledge, there are the petrified remains of trees from a long destroyed ancient forest.  Possibly by a volcanic eruption from Mt Taranaki.  I call this the Mega-Wall for obvious reasons.

The top layer consisting of sand and volcanic ash excepted, these cliffs, despite being composed of the same interbedded mudstones and sandstones, are, despite being subjected to the most ferocious wave pounding action on the Tongaporutu coastline, the most stable cliffs on the entire Tongaporutu coastline.  Counter-intuitively, these waves, rather than destroying, have created a cliff structure that has been battle hardened and highly smoothed into a fortress-like two dimensional Trojan ‘wall’.

Put simply, the smoother the cliff surface area is;  that is, the more two-dimensional the surface area, then the more stable it is.  Such cliffs are ‘wall-like’ in appearance with little three-dimensionality evident.  I believe that such cliffs are built from site-specific (unique topography) wave action.  That is, such is the force applied, that the rock particles are forced closer together due to compression.  (The spaces that would normally separate the particles are shrunk to the point of either being eliminated or nearly so, so that the particles in effect ‘join up’ and ‘harden’ into an unyielding, stable wall.  Obviously, gravity induced compression is also a major factor - all cliffs are subject to it, but gravity alone does not build wall-like cliffs such as the ones located here.

Another important point with regards to smoothness is, the smoother the surface area is, the less susceptible it is to resistance and friction.  The smoother the cliff or rock’s surface, the more dolphin-like it is.

Of course, the force applied has to go somewhere, and it does.  It goes inward and upward.  Such cliffs undergo what I term wave-induced ‘wave-quakes’.  At the Wall, the vibration from such quakes travelling internally through the cliff has built Cathedral Cave.  Cathedral Cave was thus not primarily built from direct wave action as one might assume, but indirect wave action.  (Wave generated force).  This is perhaps better termed as a ripple or wobble effect.  The wobble effect is particularly noticeable in the loosely packed cliff top sand/volcanic soil strata.

In such sites the top down erosion tends to be significant due to the soil particles being more loosely packed than average.  This makes these sites highly vulnerable to rain and overtopping storm wave spray plumes.  In fact, we have a classic case of opposites.  While the lower cliffs are ‘super-hardened’, the upper cliffs are ‘super-soft’ in a roughly 60 to 40% ratio.

Thus, though the appearance is of top down erosion failure, the reality is cliff collapses are in the main, induced from the bottom up.  Less give at the base, more give at the top.  This is true to varying degrees of all the cliffs on the Tongaporutu coastline.  Fracture lines tend to radiate from bottom to top.  Specifically, these fracture-lines are wave-induced.  They are separate from and additional to the fracture-lines that are already inherent in the interbedded rock stratas.

Conversely, the more crumpled the surface area is;  that is, the more three-dimensional the surface area, then the less stable it is.  Such a surface area is highly susceptible (particularly along inherent fault-lines), to vertical fracturing by waves.  Generally speaking, the force delivered by waves on such crumpled cliff surfaces, tends to be preferentially diluted.  Thus there will be a lot of activity of varying magnitude, directly related to the crumpling.

Paradoxically, the smoother the total surface area at a given site, the more catastrophic the collapse tends to be, but also the less frequent.  And, the more crumpled/fractured the surface area, generally the less catastrophic the collapse, but they occur more frequently.

This is a generalization because a large, relatively smooth area with minimal or no fracturing, or, a wide rock strata composed wholly of mudstone or sandstone, can result in a large chunk collapse which doesn’t automatically evolve into a catastrophic collapse.  Conversely, the opposite can apply.  That is, a highly crumpled/fractured surface can cause a catastrophic collapse.  The key to either is how much a particular collapse affects the immediate area surrounding it – specifically, how it affects neighbouring fracture lines.  Do they aid or inhibit collapse evolution?  This would be known as a flow on or site specific ripple effect.

If the initial collapse flows on into a full scale catastrophic collapse, then the ripple effect can extend far beyond the original site specific collapse zone.  The distance the ‘ripple-quake’ travels in all directions is determined by the magnitude of the collapse.  Thus, the larger the collapse, the greater the distance travelled.  These ripple-quakes destabilize susceptible fracture lines in other previously unconnected sites.  These ‘daughter’ site collapses may occur within hours of the ‘Mother’ site collapse.  Conversely, it could be months before one or more daughter sites collapse.  This could lead one to infer that there was no causal connection to the original Mother site collapse because of the distance involved in terms of both distance length and time length.  I also believe that in all cases, both of these lengths, (distance/time) are fractal in nature.  That is, they scale according to fractal principles.  (This can perhaps be converted to a mathematical equation if it hasn’t already been done by someone).

I have put this description in here as opposed to the Overview on Cliffs because photographs taken from the cliff top here looking down on the Wall and north along the Four Brothers Beach best illustrates these points.

2001

 

 

PHO2008_823

PHO2008_824

3.1.2001   PHO2007-194,   PHO2008-823-824

PHO2007_194

This was the first time I visited what I later called the Gibbs’ Fishing Point.  These images show the Wall and look north along the Four Brothers Beach.  The erosion here above the hardened cliff face was quite severe.  PHO2008-823 actually looks down on Beach One, but I have also included it here because this viewpoint is the southern boundary of Gibbs’ Fishing Point.

4.2.2001   PHO2008-830, 836, 841

Though high summer it was quite rough.  I was particularly interested to see how the waves impacted on the Wall.  This is detailed in Section Two on Weather.  PHO2008-836 shows part of what I called the ship’s bow formation at the base of the cliff.

2002

27.4.2002   PHO2007-195, PHO2008-859, 864 and 865

The weather was quite calm and overcast.  This shows a more oblique view of the Wall, but gives a better indication of the erosion.  Also, part of the ship’s bow formation at the base of the northern end of the wall is visible.  The overall view looks north with the Four Brothers Beach to the rear.  There is also a close-up of the erosion.  PHO2007-195 shows the ship’s bow formation at the base of the Wall.  PHO2008-864 shows the severe erosion on the seaward (western) side of the Megal-Wall with its attendant rock stack, Gull Rock.

2003

1.1.2003   PHO2008-877

This shows part of the fishing ledge complete with fishermen, from which the Gibbs’ Fishing Point derives its name.  The Wall is partly obscured to the right with the Four Brothers Beach tracking north from this.

27.4.2003   PHO2008-884

The Tongaporutu Impermanence Project proper started on this day.  This evening shot gives a close-up view of the Wall.

10.6.2003   PHO2008-017, 907, 914

During storm conditions, being at the Wall can be both an exhiliarating and terrifying experience at the same time.  On this particular evening there was a roaring, bitterly cold southerly that also chilled to the bone.   PHO2008-914 is one of my favourite images.

11.6.2003   PHO2008-023

Extreme erosion.  The vegetation, mostly grass, is badly affected by wind-whipped salt-laden wave spray plumes that power up and over the high cliffs under conditions such as those experienced on the 10th June.

30.6.2003   PHO2008-027, 030, 924

There was a stiff northerly with a vigorous sea running.  The low angle of the winter sun combined with wet spray on the Wall made it ‘light up’.  See PHO2008-027.  The other images show more of the erosion.

27.7.2003   PHO2008-064, 967-968

Overcast conditions made for even light photography.  PHO2008-064 was taken from above the Wall and looks across to where I photograph looking back towards the Wall and the Four Brothers Beach.

13.8.2003   PHO2008-171-172

CLIFF SEQUENCING.  These images were taken of the small cove located at the base of the Wall.

6.9.2003   PHO2008-207, 1026-1027 and 1030

These images highlight big wave conditions at the Wall.  I also used my 300 mm telephoto lens to obtain a closer view of the ship’s bulb formation at the base of the Wall.

29.9.2003   PHO2008-219, 1035

Alpha Storm.  The wash zone extended so far out to sea, that only ‘wash waves’ splooshed up the cliffs.

1.12.2003   PHO2008-446, 454

This was the first time I accessed the fishing ledge proper.  I found it to be quite a scary place.  I photographed it looking both north, with the fisherman and south, with Gull Rock.

3.12.2003   PHO2008-458

I had accessed a newly discovered vantage point on the MacKenzies farm that I called the Brothers Overlook.  This gives viewpoints looking both north and south along the Four Brothers beach.  I had specifically come up on this day, despite it being drizzly and with wall to wall cloud, to photograph the Brothers rock stacks with a variety of different lenses.  One of the lenses was my 300 mm telephoto.  I brought this up to photograph terns nesting on the oldest Brother.  There were big waves splashing up the cliffs and at Gibbs’ Fishing Point in particular.  Despite the dangerous sea conditions, there were some people fishing from the fishing ledge lower down.  The photo shows Gibbs Fishing point from a fresh viewpoint.

2004

23.1.2004   PHO2008-537

This image was taken as part of cliff sequencing on Beach One.  However, I have also included it here because it marks the southern boundary of the Gibbs’ Fishing Point.  The view itself looks north and this is the northern end of Beach One.

15.2.2004   PHO2008-1219

SUPER-STORM EVENT.  Super-Storm One.  Though it was pouring with rain, there was no wind at this time.  The wind, when I ultimately slammed into it in the Uruti Valley on the way home, was from the south-east, an unusual quarter for heavy rain for Tonga.  This storm caused massive damage in the lower North Island.

22.2.2004   PHO2008-680, 683-684, 1221

SUPER-STORM EVENT.  Super-Storm Two.  The whole cliff shook each time a very large wave whoomped into the cliff’s base.  Massive spray plumes overtopped Gull Rock and the very high cliff here, scorching the grass for some distance inland.  Small branches and stones were evident but I didn’t photograph them.

29.2.2004   PHO2007-206 and PHO2008-697

SUPER-STORM EVENT.  Super-Storm Three.  This caused a huge amount of erosion.  The amount of rain that deluged Tonga was mind-blowing.  In fact so much rain fell that it practically ‘melted’ the Whitecliffs Walkway road.  The reddish colour of the sea was due to the massive soil bleeds that occurred on Beach One.

7.3.2004   PHO2008-714

This gives a rare view of the mega-wall at beach level.  This photo was taken from the Beach One end of Gibbs’ Fishing Point.

2005

20.8.2005   PHO2008-1399

This illustrates the cliff on the Four Brothers Beach side of Gibbs’ Fishing Point.  It also shows the prominent ‘ship’s bow’ buttress formation at the base of the cliff.

21.8.2005   PHO2008-1429

This is similar to the photo taken yesterday, the 20th of August, except that it doesn’t show the ship’s bow formation.

19.9.2005   PHO2008-1439, 1444, 1450, 1452-1453,

Alpha Storm.  Most of the information relating to storms/weather pertaining to Gibbs’ Fishing Point will appear in Section Two on Weather.  The reason I have put an entry in here is to show the storm’s effect from both the seaward side of the Wall and from the Cathedral Cave side.  They show one spectacular consequence of ‘wave-quakes’  - the creation of Cathedral Cave.  They will also eventually cause its destruction.  As with the other storms, wave spray plumes that overtop the very high cliffs here, and more especially the lower Fisherman’s Ledge, sometimes deposit smallish rock and tree branch debris.

11.12.2005   PHO2008-2532-1533

It was very hot.  PHO2008-1533 shows a rain front advancing towards me and the Wall.  There was no wind preceding it.  PHO2008-1532 shows the same rain band just as it hits.

2006

4.1.2006   PHO2008-1536

A summer storm photographed at the Wall.

31.1.2006   PHO2008-1564, 1566, 1572-1573

I managed to do some aerial photography when Sticky Pictures were filming me and my Impermanence project for an upcoming Te Papa exhibition entitled Earth, Wind and Fire.  The images show the remarkable wall-like cliffs that are a feature of the Gibbs’ Fishing Point.  Gull Rock is on the seaward, western side of what I later called the Mega-Wall.  Unfortunately, most of these images aren’t sharp.

1.3.2006   PHO2008-1583, 1585, 1586, 1587-1588 and 1590

Due to an extremely low tide of 0.0, I was finally able to round the ‘ship’s bulb’ at the base of the Wall and to access the small cove to the rear of Cathedral Cave.  This remarkably smooth cliff face is regularly slammed with huge waves.  The shock-waves that they generate created Cathedral Cave.  The cave’s length of 100 feet closely matches the length of the external cliff face, or wall.  Two small blind caves were forming in the cove’s corner and a stream tumbled down from the cliff above them.   These images give a ground level perspective of the huge waves that smash into the Wall.  If powerful enough, 100 foot spray plumes overtop the cliff and drench the vegetation high up and further back up the cliff.

10.4.2006   PHO2008-813,1617

I specifically went up to Tonga to do some moonlight photography.  PHO2008-1617 was taken while there was still some late light.  The clouds didn’t hold out much promise of a great moonlit night, but I did manage to get one decent image.  PHO2008-813, being a time exposure, shows the sea state as a silky wash.

20.6.2006   PHO2008-1925

This is a standard image of the Wall.

2007

23.6.2007   PHO2011-1007

The Wall under turbulent weather conditions.

2008

23.1.2008   PHO2011-1151-1152

The remnants of Cyclone Funa hit on Tuesday  with north-westerly gales.  As I stood atop GFP, the whole cliff shuddered on a number of occasions as waves pounded the cliff-face.  I also photographed Gull Rock and some of the erosion ridden upper cliff.

10.2.2008   PHO2011-1160, 1178

I had just two frames left on the roll of film in my camera.  I only took one photo of the Wall.  For a change I timed the wave at its maximum explosive action.  Later on, after the rain came a great sunset.  Unfortunately I couldn’t be in the two best spots at once.  After rushing back to the Wall from the Fledglings’ Overlook, I just lucked out.

 20.4.2008   PHO2011-1209, 1211

I continue to document the evolution of the Wall.  PHO2011-1211 shows part of the Mega-Wall from the fishing ledge proper.

3.6.2008   PHO2011-1239

I hadn’t planned to photograph at the Wall, but the light was such that I couldn’t ignore it.

 

 

25.6.2008   PHO2011-1240

 

The weather was certainly different at the Wall today.  Though this photo may be boring, their purpose is to document the Wall under changing conditions and how in turn those conditions change the Wall.

 

 

24.7.2008   PHO2011-1262

 

SUPER-STORM EVENT.  Super-Storm Two.  The Wall came through this relatively unscathed.  Other parts of the coastline weren’t so lucky.

 

 

28.9.2008   PHO2011-1319

 

This is just a standard shot of the Wall.

 

 

 

2009

 

 

22.7.2009   PHO2011-1618

 

The erosion at GFP, the part that looks across to the Wall, appears to be more pronounced.  Also, the cliff appears to be more hollowed out at the crack that is gradually being carved out at the base of the Wall.  This is immediately to the rear of the ship’s bow type prominance that marks the outer entrance to Cathedral Cave.

 

 

2.12.2009   PHO2011-1687

 

I haven’t photographed here for some time.  Partially due to laziness and that I have been here often in the past.  Still, I needed to come back and get refreshed.  For the past three days there has been wall to wall sea fog and low cloud.  I wanted to get some mood photography done, and this was one spot I wanted to photograph.  The conditions didn’t disappoint.  The fog came in and lifted on a semi-regular basis.  Also the light levels kept changing quickly, making metering difficult.

 

The Wall appeared little changed, although the area being carved out immediately to the rear of the ship’s bow prominence at the base of the Wall appeared to be growing.

 

The sea was choppy and brown in colour.  This was due to the sandy bottom being churned up.  The north-westerly breeze, being directly off the sea was cool, but otherwise the conditions weren’t really unpleasant.  And it wasn’t raining.  The cliff-top foreground detail looked particularly attractive in this light.  Usually the nude cliff top is quite harsh, particularly in bright light.

 

2010

 

 

31.3.2010   PHO2011-1796, 1798

 

This is the first time I have ever been able to access the seaward side of Gibbs’ Fishing Point.  Specifically, the seaward side of the Mega-Wall.  PHO2011-1798 shows the Wall, which I have accessed on a few other occasions.

 

 

16.5.2010   PHO2011-1810

 

Again, I haven’t been here for some time.  However, after a fairly extended period of calm weather, a deep low which had been parked up north for some time, finally tracked south on Friday.  This delivered truck-loads of rain, thunder and lightning, and for good measure, a tornado.  This tornado was very close to home, passing a short distance above where I live on Plymouth Road.  After totalling a massive 80 odd year old macrocarpa, sending it crashing down over power-lines, I along with others, went without power for 18 hours.

 

Anyway, today, Sunday, I managed to drag myself out of the house and up to Tonga.  I had originally planned to go to Pilot Point, but as the weather was so bad, thought I would go to Gibbs’ Fishing Point where I might get some spectacular weather shots as in waterfalls pouring off the cliffs.  I particularly wanted to photograph looking south along Beach One with White Cliffs in the background.

 

As the main style over the fence was down near the Wall, I headed there first.  I later discovered a second style which I had forgotten about at the southern end of Gibbs’ Fishing Point.  Anyway, while trying to set up the panoramic camera in a stiff on the nose northerly, I noticed that a large chunk of the cliff’s ship’s bow prominence on the Wall side had been carved off.  I had been expecting this as it was in the process of being preferentially carved out.  I assumed that this storm that we have currently been experiencing was the instigator, the weather having been relatively quiet for some time previously.  Also, it looked fresh and rock debris was clearly visible at the base.  This volatile location is not condusive to debris longevity.

 

Though the storm was going hammer and tongue further south, I lucked in with a short sun window.  I did take a second photo a little later on from lower down on Gibbs’ Fishing Point, but the sun had given up the ghost by then.

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