Volancoes of Big Island, Hawaii (Part 2)

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Dr Trevor Watts (UK)

This is the second of a three part article about the volcanoes of Big Island, Hawaii. In the first, I discussed their background and explained some of the terms used to describe the lava that can been seen there. In this part, I will discuss some of the highlights that my wife and I saw during our several trips to the island, including in October 2014.

A night walk to the flowing lava from Kalapana

This was one of the major highlights of our previous trip in 2013. Several local guides conduct walks across the old lava (mostly 1981 to 2013 flows) to wherever the current flow is best viewed. Our lead guide was Dave Ewing (postewing@gmail.com or (808) 315-2256) and our group met up at his house, located on private properties beyond the “End of the road” signs at Kalapana. This house is one of the very few to survive the 2010 flow, which came through the Royal Gardens subdivision and into Kalapana.

1. Going Away Party Panorama xx
Fig. 1. A going away party to mark the long-expected event of the house burning at Kalapana on the night of 25 July 2010. My thanks to Darlene Cripps and Gary Sleik for this picture.

We began in late afternoon, with around a dozen people in the group. The walk initially passed the remnants of some of the other homes – a corrugated roof, a fridge, some pilings, and so on, before getting onto the fresh lava. It was almost five kilometres each way and, although the walking isn’t especially difficult, a couple of hours scrambling over very uneven and lose ground can be tiring. Also, it isn’t for anyone of a nervous disposition or unsure footing, and it really does need a guide, even though you can see the rising steam and smoke from kilometres away. Getting back through pitch darkness is more difficult and, as if to prove my point, another guideless group joined ours on the return with an injured member (sprained ankle).

2. An hour later - house roof xx
Fig. 2. An hour later – the blazing roof is all that remains. My thanks also to Darlene and Gary for this picture.
The fate of Darlene Cripps and Gary Sleik’s home

The fate of one particular home is well documented. The flow that was working its way through and around the village of Kalapana circled round the back of the house, until it was three-quarters surrounded. Then, it restarted from the front, finally touching the woodwork at the foot of the outside stairs. The house was gone in a blaze within the hour, as the owners, friends and neighbours held a ‘going away’ house-burning party on the night their property went up in flames. 25 July 2010 was the final night for the home of Darlene Cripps and Gary Sleik, who took many pictures and made a DVD of the event and the guilty lava. The charred foundations are now under 12m of lava. The lobate lava that covered the area and burned the houses down was fluid and only about a 30cm deep at any one time. The corrugated tin roof collapsed after less than an hour of the fire, but then ‘floated’ on top of the lava, as it continually inflated beneath the roof over the following months.

My thanks to Darlene and Gary for allowing me to use their photographs (Figs. 1 and 2). Gary is now rebuilding his home on the same 23-acre plot; and Darlene manages the accommodation where we stayed in Kaimu: http://www.vrbo.com/460059.

We arrived in the vicinity of the moving lava just before sundown, enabling the taking of several pictures of the lava formations in the daylight. The warmth of the ground was suddenly noticeable and, as the sun disappeared, so the lava seemed to come to life. All around us, there were red glowing patches and streaks – many of them moving slowly or taking on a sudden spurt. We were completely surrounded by small flows less than a metre across. In the daylight, they weren’t visible as molten lava, but with the sun down, it was like a lighted garden park. We stayed in the area for an hour or so, watching the lobes and fronts advancing and swelling; crusting, crinkling and restarting as long tongues, pushing the surface into wrinkled, ropey masses.

Other groups were there, with or without guides, but it only added up to about 30 people all told. A few people pushed sticks into the moving surface to watch them catch fire and a few tried jumping over the molten tongues. There was no feeling of any danger (other than from foolishness), as the lava moved quite slowly and the guide was keeping a check on the overall situation. Apart from a few over-excited visitors, most people seemed to have a reverential view of the world-creating happenings around them and simply watched the new land being formed in near-silence. What made the most noise was the surface of the lava as it cooled – a thin, but rigid skin forms as the lobes slow down and settle, but the leisurely continuing movement cracks this and sends flakes scattering away, sometimes several metres into the air. The effect is much more dramatic when it rains and cools the lava surface more suddenly, at which time, there can be a veritable cloud of flying flakes above the lava.

3. Tin roof IMG_1198
Fig. 3. By May 2013, the roof is rusted and the forest is gone.

From this vantage point among the moving flow, it was possible to look down over the cliff edge (about 30m high at that point), to watch lava slowly pouring towards the sea from a variety of points down the cliff face, where small tubes had their openings. This gave an unearthly glow to the whole water surface and rock faces. However, it wasn’t possible to see the point where the lava actually entered the water.

4. Cloud IMG_1214
Fig. 4. The plume of steam and fumes can be seen for miles around.

Watching the lava forming, moving, taking shape all around is the only way to understand the wondrous nature of the stuff – how the various shapes and twists are created, and take on such superbly varied (yet similar) shapes and patterns. Observing it actually happen gives so much more meaning to what you are looking at when walking on cold lava here or anywhere else in the world.

5. evening glow comes on IMG_4523
Fig. 5. As evening falls, all around there seem to be glowing patches and cracks that you hadn’t noticed in the full sun.

The walk back to the house and car parking was in complete darkness, apart from carried torches or flashlights. It would definitely not have been easy without a guide, especially as the lava flows here were changing on a daily basis. It only takes a moment for one lava front to stall and another to break out close by, or at a distance of a few hundred metres, for there to be problems. The internal pressures within lava flows are constantly built up and released – inflating one lobe for a time and stalling another.

There had been news reports of two people being severely injured earlier in the year, when a foot went through the newly-formed lava skin. During December 2014, it wasn’t possible to do this walk, as the lava stopped moving in this direction late in 2013. Once the current ‘June 27’ flow has settled, it might well be possible to conduct similar day or night walks to the new flow and there are several Internet sites with close-up footage of the flows already. Or Madame Pele might change her mind again and send the lava flowing southwards to the sea once more. Check the Hawaiian Volcano Observatory (HVO) site for daily updates and maps at http://hvo.wr.usgs.gov/activity/kilaueastatus.php or just Google HVO.

6. Lobes and ropes down the slope IMG_4561
Fig. 6. Moving in lobes and rope patches down the hillside, the lava seems to cover the whole slope.

The lava-falls at the ‘Ocean Entry’

In 2008, we visited this area for a short stay and it was a time when the lava was entering the sea a few kilometres or so from Kalapana. The access was controlled by the Civil Defence, just past the ‘End of the road’ signs on Highway 130, where the lava had swallowed the road in a number of flows over the previous years. The column of rising steam and smoke could be seen from at least three kilometres away in Pahoa, driving from Hilo. There was a large car park and a street market, with dozens of enterprising stallholders, some with general merchandise and others with lava-related items, such as lights, drinks, lava ashtrays and photographs of the lava and lava caves.

Some of these photographs had been taken from the stern of boats that had backed up perilously close to the lava-falls, to peer inside the active tubes from which the lava was pouring out. The cameramen had to wait until a large wave lifted them to a height sufficient to see inside the lava tubes and take a quick photo, then rev up and depart swiftly. For such bravado, they deserved every cent of their charges for the terrific quality of pictures.

7. boat gets close IMG_4609
Fig. 7. The sight-seeing boat is getting a closeup view of the lava entering the ocean.

A twenty-minute walk from the car park led to a viewing area a few hundred metres from the active drop into the sea. As we approached, the plume was extremely impressive, particularly the sight of tornadoes within the plume and coming from it. These spun out of the main, hot centre of the steam, whirling away, spinning and twisting until they cut loose and drifted off, to be replaced by another. Closer approach was not permitted, although we did see a few people going over the private land closer to the lava. It was impressive by daylight, with great columns of smoke and steam shooting skywards over our heads. Blasting up through the steam, there were frequent spatter explosions of red lava flying high.

Within the steam plume, there were constant sudden updrafts, like vertical tunnels of rock and steam sucking powerfully upwards; followed a moment later by a fall of fine ash, turning the cloud to a mass of dark descending curtains. At times, there would be an especially loud thump, denoting a steam explosion, where a particularly large mass of lava had tumbled into the water and flashed some of the sea into steam. These would result in huge masses of lava fragments and hot cinders hurtling perhaps a hundred metres upwards, and lots of oohs and aahs from the audience.

8. Lobes and flakes IMG_4551
Fig. 8. Lobes of glowing lava cool within a minute of forming; the flakes that spit off can be seen on the grey cooled patches.

Although it wasn’t possible to see the lava falls hitting the waves, the sea was visible a little further out. The water was steaming heavily and giving rise to whirling tornadoes across the surface. They varied from a meter or so across to the size of a boat – and there was a boat among them at times. This looked incredible – imagine the view that those people must have had – until a particularly large blast sent glowing fragments over a huge area and the boat retreated. Local gossip says that one boat owner has lost two vessels on these forays. Sometimes, there was just the one tornado spinning away and, at other times, there would be a train of them heading out to sea, to disappear as they cooled and lost their source of power.

9. A beautiful runnel of ropey lava IMG_4545
Fig. 9. A beautiful runnel of ropey lava already beginning to crust over, even as it is only exposed for a few seconds.

Even more amazingly, there were several helicopters buzzing around the whole steaming plume. This was a must, so we were up there two days later as part of a volcanic highlights helicopter ride. We did get as close as it appeared from the ground and it was very spectacular. Photographs were difficult to take, as the craft was being buffeted about in the hot swirling air. Views looking down into the exploding mass are especially interesting, when the fragments are heading straight up towards you.

10. night steamIMG_4666
Fig. 10. A final look back at the spectacular steam cloud lit from beneath, as the lava-falls enter the water.

As the sun dropped, so the glow from the lava picked up and the steam clouds were lit from beneath in great roiling masses. These were extremely spectacular – red clouds blasted by frequent explosions of lava fragments, rising majestically into the gathering gloom. Particularly noticeable was the colour contrast between the glowing steam clouds here and the sulphurous clouds emanating from Halemaumau far away in the background, illuminated by the sun behind them.

In the later evening, the glow within the plume intensified from the dull red ball that it had been and took on the appearance of boiling swirls, illuminated by explosions and short-lived fire fountains. This was breathtaking. The viewing area is not open all night and is locked at 9.00pm. The car park is still there and accessible to lava-walkers during the daytime, and so are most of the signs warning about the eruption and the opening/closing times – six years after it ended. However, this is likely to change very shortly, as this is the Hwy 130 road that is being reconstructed across the earlier flows in case the new lava blocks it north of Pahoa.

1. View of the plume from south of pahoa P1180255a
Fig. 11. A view of the steam plume from several kilometres north, near the town of Pahoa. This illustrates how enormous it was and how high it rose into the sky.
2. Helicopter and air-borne tornado P1180428a
Fig. 12. A helicopter against the steam cloud. The ‘V’ shape in the bottom right quarter is an airborne tornado, originating within the plume and rapidly spiralling directly away from the camera.
3. A strong explosion P1180498a
Fig. 13. A particularly strong steam explosion, as a result of a large mass of lava falling into the ocean and blowing itself to fragments.
4. A particularly heavy fall of fragments P1180467a
Fig. 14. The resulting heavy ash and fragments fall after an especially violent explosion. The ridge on the right is made of ash and cinders, which have been deposited during the five-month period that the ocean entry was at this point.
9. Evening fire fountainP1180800
Fig. 15. Into the evening, the lava explosions take on the appearance of temporary fire fountains.

Boat trips to the lava falls

Inspired by seeing where the boats went in 2008, we decided to take a boat trip along the cliffs to experience all this for ourselves. At around four in the morning, we took a boat out the Pohoiki Harbour at Isaac Hales Beach Park, about 20km northeast along the 137 road from Kaimu. Then, it was a rough boat trip back along the coast for about an hour and a half, feeling battered and queasy. The paucity of steam clouds should have alerted us more. Arriving at the scene of the lava falls, all we could see was the exit of one tube partway down a cliff face. Inside, there was the glow of lava, but the active flow had stopped, maybe a couple of hours before we got there.

We checked further along the coast for a half-hour, where other falls had been flowing the day before, but there was nothing and, when we returned to the first large tube exit, the glow was entirely gone. After five months, it had stopped moments before we arrived. True, the cliff face was interesting, with a vertical cross-section of the newest land on earth, but it wasn’t what we’d come for and I still haven’t recovered from the disappointment. Even the giant waves battering the cliffs in spectacular crashes of spray didn’t help.

1. Steaming black sand heaps P1190437
Fig. 16. The cliffs, topped with mountains of black volcanic sand. These are actually obsidian fragments, which are still steaming with internal heat.

We had another go in 2013 and our early morning boat cruised along the face of the cliffs as lava poured into the ocean, getting as close as a few metres and considerably less than ten metres at times. It was absolutely spectacular and, when the steam cleared, we had fleeting glimpses of red-hot lava falling and dribbling down the cliffs. I think this added to the awe – making it something special when the steam blew aside for a few moments. We went to several sites along the cliffs – over a distance of perhaps a kilometre and had superb views of lava dropping five or ten metres in some places, or as a broad sheet in others.

However, the most utterly wonderful trip was an evening voyage the following day, when the lava was flowing at its height. Seen from kilometres away, the steam clouds were very promising and, even as we approached the first mass of fire and steam, another one started up about a hundred metres further along. The boat captain said that one group of falls that was there in the morning had vanished altogether, showing that they are in a state of constant change. As we were watching during the evening, another set of bright falls started up a few hundred metres further along the cliffs.

7. An idea of the proximity - under twenty yards away2
Fig. 17. An idea of the scale and closeness of the boat to the falls – less than 20m away for much of the time.

The evening there, tossing about on the waves 20m away from lava falls in the dark, was the most memorable sight I have ever experienced – and in 70 years, I’ve seen some good ones. Brilliant lava streams poured down the cliff faces into the red-reflecting waves. Steam flashed everywhere. There were exploding blasts from time to time, sending lava bombs into the air. Some of these landed close to the boat and fizzed madly around for a minute, before succumbing to the cooling water – a bucket of seawater hauled aboard was almost too hot to place a hand in it. There was also water to douse any lava that might land on the decking.

Strangely, there wasn’t any feeling of danger, even though lava bombs, almost half a metre across, were whizzing through the air and landing in the water around us. Our boat moved to different locations along almost a kilometre of the cliff face, where the lava was pouring into the waves, sometimes in high vertical falls, sometimes splashing and washing over rocks created only moments earlier. When, or if, they start up again, they have to be the highest priority on anyone’s ‘bucket list’. I count myself as one of the extremely fortunate few to have witnessed such an awesome sight.

Fig. 18. A memorable ending to a memorable evening, as the boat pulls away for the return to Pohoiki Harbour.

A walk on the lava at Kaimu and Kalapana

In this area, from just over a kilometre east of Kaimu, down through Kalapana and into the national park, there are innumerable vistas of multiple forms of lava. Best seen in low light when the shadows etch out their forms, they are especially spectacular at sunrise and take on warmer glows in the sunset.

This area of lava has a complex history. The village of Kalapana was built on old lava flows and was swamped by new ones in phases from July 1986 to February 1992. The whole eruption had begun on 3 January 1983, when fissures opened up along the eastern rift zone, east of Kilauea’s summit. Fire fountains up to 480m high filled the air, but very quickly the outpouring coalesced at one spot. This formed one main cone, about 250m high forming a hill. This cinder and spatter cone was informally coded ‘O’ by the observing volcanologists, who were surveying a line of fissures and vents. It then became Pu’u O (Hill O) and then Puʻu ʻŌʻō, which means both the o’o bird and Pele’s (the Hawaiian Goddess of the Volcano) stick for digging volcanic pits.

10. Longer-lived ooze mound
Fig. 19. A mound that was pushed up to exude small runnels of lava down its slopes. There are many such cones near the national park boundary, west of Kalapana.

The first three years of eruption produced mainly a great amount of a’a lava, which slowly spread far and wide from the two vents of Puʻu ʻŌʻō and Kupaianaha (slightly to the east of the main cone). Afterwards, these vents flowed fairly vigorously, as the exuding lava became hotter and more fluid. Presumably, the magma chamber was refilling with hotter, more fluid magma from beneath. It flowed away as pahoehoe lava – ropey and lobate – that formed long and wider-spreading smooth-surfaced flows.

These crept over the flatlands and swept further and faster down the steeper cliff and hillside sections, south for up to 13km, covering many square kilometres of forest and cultivated land. The lava eventually went across the Chain of Craters Road (HWY 130) that runs near the coast. It did this at various times, sometimes over the re-built sections of road. Very frequently, the fluid lava was again replaced with slow a’a flows and these, in turn, were often overrun by more pahoehoe flows. By the time it finished, the eruption had buried some parts of the road up to 15m deep, over a distance of 13km. Towards the end of the eruption, the lava was again flowing towards and into Kalapana in a series of pulses. A number of homes were swallowed during the summer of 2010, and with the phase not ending until late 2013 or possibly early 2014.

The lava is basic basaltic lava, with a relatively low silica content, which makes it quite fluid. Therefore, close to the issuing crater, it will flow relatively swiftly, up to about 16kph, if it is confined within a channel where the edges or walls have cooled and solidified, or if contained within an underground tube. Such tubes are often formed where a channel has crusted over, but the lava continues to flow beneath the ‘roof’. One such tube towards Hilo is almost 66km long – the Kazamura Tube. (Others include: Thurston, on the rim of Iki Kilauea; Kaumana just west of Hilo; and the Hu`ehu`e lava tubes, a few kilometres north of Kailua-Kona.)

Mostly, such flowing does not produce a large feature on the surface. It mainly acts to get the lava somewhere else quickly. This can be many kilometres away from the originating crater or vent, with little loss of heat and fluidity, so it may then break out of its crusty lid far from where it started. Such breakouts are usually where the gradient slackens off and the lava has to slow down. It ponds back and needs to burst out of its constriction. Once it is exposed on the surface, it is generally still hot enough to flow, but the slope is not sufficient for it to move rapidly and wildly away. Rather, it spreads slowly, seeping onto the landscape, and the surface cools quickly, usually within a minute of being exposed if the flow is slow, to become stiff and then solid in the space of a few minutes.

11. White mineral deposits IMG_2153a
Fig. 20. White encrustations, in this case, the result of mineralisation, not burned trees.

At the main time of their desolation, beginning in 1990 and lasting most destructively for nine months, much the same thing happened around Kalapana and Kaimu. Flows burst out from channels and tunnels, and began to spread over the land, changing direction, and stalling and restarting on a daily basis. The effect of all this was inflation of the surface of the lava and unpredictable breakouts throughout the flow. This gives rise to an infinity of fascinating shapes to delight the eye and the imagination. It is all the result of cooling lava that swells, becomes wrinkled, seeks a finger-like way out or pops out in bubbles. As well as the inflation, the loss of lava from under the surfaces causes deflation and the whole mass can sink again and crack apart. This very changeable process continued until 2014, with the exact point of ‘ocean entry’ changing its location now and again.

Access to this now cold flow in the Kalapana district is easy and unregulated. We were staying in accommodation at Kaimu that had its own private access to the lava beds, but it is equally possible to stop along the road and walk directly onto the lava or drive to the end of the road at Kalapana. There is an irregular farmers’ market here and a regular general store that was a restaurant/diner until recently). From the public access at Kalapana, a walk in any direction will take you over magnificent formations of lava. Probably, the most beautiful are a little to the east, where the lava flowed over and through the rainforest and found its way to the sea. The flow is less than a kilometre wide, between the forest/road/buildings and the low sea cliffs, but it seems to have examples of all possible kinds of pahoehoe formations.

It is still very apparent that the lava here came in phases: in some spots, it may have piled up several metres in a day or a week before breaking out sideways and flowing along another route for a time, before again stalling at one front and breaking out elsewhere. In many places, it is also clear that, the flows were very thin – only a couple of centimetres or so thick – being shortly overspread by another flow and another and another. This had several effects: where the lava has split apart and exposed cross sections. The layers can be clearly seen in different textures and surfaces, and often in vividly differing colours – yellow, orange, red and black, which is often evidence of steam that oxidised the lava while it was still hot, perhaps because there was heavy rain at the time of the flow or because of later water and steam being forced through the cooling lava.

Even as the lava flows cooled, they were being disrupted from the sides and from beneath, where fresh masses could accumulate beneath the extant surface and the pressure splits the solidified surface layers apart, producing deep cracks. Where the lava re-commenced its flow beneath the earlier layers, it often squeezed between the successive layers. This produced the effect of layered cream cakes, with the lava being pressed out sideways and exposed where the cracks from earlier disturbances had opened up the surface. In such cracks, there are often numerous layers of red lavas forming the base material, with the newer, squeezed-in lavas remaining black.

The effect in some places is very striking. In the bottom of the chasms formed by the cracks, there is often a pooling up of lava or even an overflowing of fresh lobes onto the surface. However, other cracks, equally deep, may not have any new lava in them. These are more likely to be the result of the surface all around sinking and leaving part raised, with gravity causing the cracks, as the surface is left unsupported by the drained-away lava.

This must surely be one of the best – if not the best – places in the world to see pahoehoe lava. It exists here in a perfection of forms – in great cables of thick ropes that piled and curled over one another, so slowly and remorselessly. Of course, they are not ropes, even rocky ones – they are the wrinkling surface of the flowing lava. As it cools on the surface, it is dragged along, pushed aside or forward, stretched or compressed, giving rise to all the surface forms that are created. Bubbles arise. Some burst, with others freezing and remaining forever enclosing their gaseous contents. Solid ‘blebs’ can push through the thin layers and will either flow aside for a time, as a briefly-wandering tongue of lava, or cease where they surfaced to produce a plain ball in the middle of an otherwise smooth or finely-ropey patch of lava surface.

In other places, the lava surface has been partly sucked back into the depth of the flow, producing whirls and whorls of ropey surface. At times, the flows seem to have moved in pulses, producing a surface pattern that is striped rather than furrowed.

Where the surface had crusted and then been disrupted, sections of the surface sheets have been turned over or on their sides. Commonly, these surface sections have then been fixed in a vertical position and they can now be seen with the graduated steam-oxidisation layers cutting across the surface of the ropey lava. This clearly indicates that this oxidation continued long after the lava had ceased to move and flow. In other places, the steam has seeped through cracks in more solid sections of flow, and has changed the composition of the lava and coloured it much paler – often a white or yellow tone alongside long thin cracks.

The yellow tone is mainly due to formless sulphur deposits, which do not usually form the classic needle crystals. However, the white deposits can be the result of either ash from incinerated trees or mineral deposits of manganese and other trace elements. In the case of burned trees, the white material is spread loosely on the surface and there are usually other traces, such as a mould-hole where the tree stood or the remains of branches. With mineral deposits, the white material tends to be around and in cracks.

Although the overall impression of lava is a dark steel or silvery grey, blue and green are common in the detail of the lava. This is especially so on the undersides of broken pieces, which have not been exposed to weathering for long. Even a brilliant yellow-silver is seen on some freshly exposed. The potential colours depend on the precise mixture at the time of extrusion and cooling. Commonly found minerals in mafic lava such as this include silica (the oxidised form of silicon), which is the main component of quartz, olivine, pyroxene, amphibole and biotite mica, along with magnesium, iron, aluminium silicate and potassium. Mostly, they are impure, oxidised or mixed into each other.

The time taken to cool down is surprisingly important, because cooling slowly allows some minerals to separate out and crystallise, and give a more distinct contribution of their own colour to the surface. This is called fractional crystallisation and is seen well in silica-rich lavas, such as this basalt. Some exposures will change colour as they are exposed to the weather, for lava that is initially blue, as it loses its blue lustre and becomes greyer. Silvery pearl-grey surfaces frequently become darker after prolonged exposure. Heavy rain at the time of eruption can cause increased oxidisation and a subsequent intensification of colouring, especially in iron-rich lavas. Rapid cooling on a cold day can produce a glassy surface, which will have its own range of refractive colourations that vary a little, according to the angle they are viewed from.

An unusual feature – we hadn’t noticed it before, anyway – was the imprint of solidified flows on the underside of later flows. It seems that one flow had travelled over an earlier one, cooled and solidified. Later, as the whole flow was disturbed by new flows, the surface broke up and the two layers split apart. In rare cases, the underside of the upper layer bears the imprint of the surface of the lower one – a sort of negative pint or trace fossil. The example here is from the cliff-top close to Kaimu.

More commonly, where semi-molten layers have been forced apart (perhaps by gas intrusions), the underside of the higher one displays ‘suck and pluck’ textures. These are very sharp and jagged under-surfaces that have been plucked apart while still partly molten. Sometimes, these pull completely apart and create slabs with one extremely sharp surface; and sometimes they do not completely separate and produce a cave-like gap, with its own fangs.

14. Jagged sections pulled apart IMG_2258
Fig. 21. Where the crusting surface has been incompletely pulled apart, the formerly joining surface can be extremely sharp and jagged.

From the road, the coast here is just a few hundred metres across from the lava field. The cliffs are not high – mostly about ten meters to perhaps 30m in places – but they have black-sand beaches and great Pacific rollers crashing onto them. To see the new land being already broken up and washed away by huge waves makes for an awesome pause from walking the lava. Much of this coast was formed around 1992, when the old coastline was overwhelmed and a new one extended just under a kilometre outwards in places.

15. a'a flow along the coast IMG_0796a
Fig. 22. Along the coast at Kaimu. The a’a flow tumbled over the pre-existing cliff and now makes access along the coast difficult.

To the northeast of Kaimu, the cliffs are topped with a’a lava and are not easily accessible from along the beach front or through the rainforest. Those a’a flows can be accessed from the Hwy 137 road, between Isaac Hale Park and Kapoho.

Tree and fruit impressions

In a few places, there are impressions in the lava of tree trunks. These are most spectacular and prolific just west of the end of the road at the existing part of Kalapana village, where the general store, village and car park are located. They are all within one kilometre of the road and are easy to find.

4. seed cast 2IMG_4266 - Copy
Fig. 23. Fossilised impression of an oil-palm seed, almost head-sized.

As they were formed in the last few years (since 2008), many of the impressions are very clear and fresh. They were formed as the lava crept through the forest and farmlands here, and set fire to the trees and brushwood. Some trees remained standing and eventually burned away, leaving a round hole where they had stood in the lava. Others fell onto the still-molten surface and burned there. These were a mixture of ohio trees, oil-palms, coconut palms and lauhala trees, as well as a variety of smaller shrubs. Their fruit (coconut and hala seeds) are also remarkably well preserved. These are already trace fossils and will continue to be so when the lava next comes this way and buries them again.

6. Where once there was a tree IMG_2047
Fig. 24. Where once there was a tree – now only the hole and the space where the roots had been.

It is very exciting to explore this area and find one print after another, each better than the last. Some trees have been completely covered by the lava in places, while others have rotted or burned away, leaving a tunnel in the lava, in some cases forming a network of small ones where trees and branches were piled on top of one another. These holes and tunnels are of benefit to future growth here, as they form traps for seeds and for rotted material for them to take root in, as well as to gather water.

9. Ground stresses are set up by the steam. IMG_2038
Fig. 25. A great many of the cracks in the lava closely follow the line of tree trunk imprints, probably because of stresses that built up in the lava by the production of sap-steam, as the tree was boiled and burned.

In the final part of this article in the next issue of Deposits, I will continue to discuss some of the highlights of our trip to Big Island, Hawaii.

About the author

Trevor lives near Nottingham, England and is a retired teacher, headteacher and school inspector who has had a lifelong interest in geology, particularly volcanoes and dinosaur footprints. He and his wife have travelled worldwide to visit and climb more than a hundred volcanoes – active and otherwise. A few of these visits have been with organised groups, but most have been independent, and frequently involve camping.

The other parts of this series can be found at:
Volcanoes of Big Island, Hawaii (Part 1)
Volcanoes of Big Island, Hawaii (Part 2)
Volcanoes of Big Island, Hawaii (Part 3)

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