Volancoes of Big Island, Hawaii (Part 3)

Print Friendly, PDF & Email

Dr Trevor Watts (UK)

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

1. kipuka IMG_1844
Fig. 1. One of the kipukas (that is, untouchedby- lava areas of forest).

The abandoned lava cliff at Kalapana

This is a stretch of old cliff face that is now several hundred metres from the sea. It is located among the flows of February 1992 to October 2003, but the area was re-flooded with lava between 2007 and November 2013, when the ocean entry hereabouts was blocked. The site is just under 5km southwest of present-day Kalapana near Poupou, where the Royal Gardens lava flow reached the coast. The walk is well worth the effort for the variety of lava formations, the many tumuli or blisters of lava, and the coastal scenery along the present cliffs. We were guided here by Gary Sleik, who lives on the lava at Kalapana.

2. IMG_1896
Fig. 2. The first section of cliff face, with the lens-shaped tube blocked by cindery flow.

The cliffs are backed up by a small kipuka, which is an area that was left untouched, as the lava flowed around it and therefore is still a lush, well-forested island among the dark bare lava. There are several such fortunate stretches of original forest in the area. The first section of cliff face is a tale of its history – two major flows that came over this area in the distant past, including a lava tube between them, since filled in with an very cindery flow that came though the tube and over the surface.

Behind this cliff, there are several windows down into lava tubes, which are mainly blocked up with subsequent flows and one may well lead to this lens-shaped opening. The base of the cliff is now buried by an unknown depth of fresher black pahoehoe lava. The detail of one episode can be seen in one small section, where the lower vesicular flow was several metres thick and formed slightly columnar shrinkage cracks through its depths, but also has a dark ropey lava surface. Above this, there is the clinkery a’a flow at the level of the lens-shaped tube.

3. layers of lava
Fig. 3. A small section of the cliff face, showing the junction between flows.

On the next section of cliff face, the thick basalt layers are more irregularly broken up and there is a cave entrance at the level of the new flow. This entrance is about half a metre high and little more than a metre wide. Around it, there are slump areas in the new lava, where molten lava was sucked down, perhaps into this cave or others. From the entrance, the cave had a drop of several metres onto fallen blocks and fresh flow. Although it is deep, it is not far across – the opposite wall can be seen with a good torch. It is an a’a flow above a much more columnar basalt face, with its top pediment several metres below the entrance level.

Unfortunately, the drop to the floor of the cave is a long way in the dark, especially with no way to climb out. The mass of cobwebs across the entrance doesn’t help, either. However, it is possible to look down to the right and see the next level down in the cave – the floor drops steeply to a lower level, in a lava fall underground. There are interesting dribbles and fingers of lava around the cliff near the cave, such as several openings that contain miniature grottos of stalactites and small pillars of lava. Also, along the edge of the cliff, the remains of the former forest can clearly be seen. Tree moulds are also easily visible in the cliff face, with a complete coconut cast among them.

4. cave entrance IMG_1925
Fig. 4. The cave entrance, less than a metre high at the base of the cliff.

Moving further along this cliff line, there is a skylight down into a lava tube. Around ten meters deep, the walls seem to be comprised of mainly solid basalt blocks and there are two levels at which the lava flowed for extended periods. The floor and the base of the upper level have pahoehoe surfaces. There is reputedly an extensive network of such tubes in this area, one called the Cave of Refuge, which has a variety of legends attached to its historical uses. It seems that some are several hundred metres long and some are interconnected. Once again, it is difficult to explore without a known way out or the necessary equipment. The columnar nature of the thicker lava is seen in some of the deep cracks in the vicinity.

The cliff then changes entirely in its character. This location was once an ocean entry point, where the lava exited one or more of tubes and flowed over the cliff in a mass of fire-falls. They left innumerable wonderful flows and dribbles in great variety, caught in the act and frozen in a near-vertical face.

5. cave IMG_1913a
Fig. 5. Inside the cave, showing the columnar face opposite the entrance. The flow into the lower level is at lower right, under the columns.

Kapoho Cone and Green Lake Crater

Of course, the whole of Big Island Hawaii is made of lava and this corner of Puna District is no exception. From Kilauea to Kumukahi Cape runs the East Rift Zone, with a parallel graben (down-faulted section). There is thought to be no direct connection between the rift faults and the graben.

1. Map of the eruption area
Fig. 6. A map of the Kapoho eruption. Cape Kumukahi is the eastern-most point of Hawaii, extended by the a’a and pahoehoe lava floods of 1960.

There have also been several volcanic events in this area. The earliest one that has been dated with any accuracy is from about’ 400 years ago,’ when the Puʻu Kapoho cone formed during a phreatomagmatic (steam-powered) eruption. The hill doesn’t look to be particularly volcanic from the surrounding area, because it lacks the conical height and angle of slope of a true cinder cone (it is only 110m high). This was extremely explosive because of the amount of water present, which is a result of its very low height above sea level.

This kind of activity formed a low, broad cone, with abundant fine particles that helped cement the ash and larger fragments and angular blocks together to form a volcanic tuff cone, which soon turned to the reddish brown of iron-rich lavas. Diamond Head, Punchbowl and Koko Head on Oahu are also tuff cones at a low elevation in Hawaii, but are much more famous than Kapoho.

2. Kapoho Hill, which erupted c1600 IMG_0980a
Fig. 7. A view across the a’a field to Kapoho Hill (Pu’u means hill), which erupted sometime in the first half of the seventeenth century, in a series of phreatomagmatic events from four fissures.

It may not appear to be especially volcanic at first, but it has a distinct rim on three sides and it is entered by the gap on the eastern flank, where the lava and pyroclastic materials flowed outwards. The track takes you up to a car park and recreation area. From here, it is possible to see down into the lake and upwards around the rim. Without contemporary accounts, it is not easy to build up a clear picture of the eruption around the 1600 AD, but there were seemingly four active vents erupting explosively, one of which produced the inner crater that began to collect water soon after the eruption ceased. This resulted in Green Lake and the water really is green – with algae. It is known to Hawaiians as Ka Wai a Pele.

3. Red-iron tuff buried by more recent lava flows IMG_1161aa
Fig. 8. Cross section of reddish tuff deposits blasted out during the very explosive, steam-driven eruption from four fissures. Now covered by more recent lavas.

Opinions differ as to whether this is on private or state land, but there is a gate and an admission charge of five dollars, which goes to local community causes, including the upkeep of the site. While we were visiting, the access from the rim down to the water was said to be closed because of damage caused by Hurricane Iselle, two months earlier. The water had reputedly been polluted by vehicles blown into it during the hurricane, although there was no sign of them or any oil on the surface – just a few damaged trees and forest debris in the lake. It is a very popular picnic spot and recreation ground for local people, and some swimmers were climbing up the path from the water when we arrived. Views down into the lake are restricted by the dense woods that fill the area, but there are glimpses of the lake from the rim.

4. Kapoho and Green Lake
Fig. 9. An aerial view of the Kapoho tuff cone, with Green Lake almost in the centre and the 1960 flow at bottom right. The almost circular shape of the crater is very clear, with the outflow coming down the middle of the picture.

We had a four-wheel drive rental car and were encouraged by the gate staff to drive to the top rim of the volcano, where there is additional parking and a picnic area. It is about a half-hour walk or five minute drive from the lake overlook. The view from the top is most worthwhile – right across this corner of the island, including all of the eruptive features from earlier and later times. Later eruptions very close by took place in 1840, 1923 (although with no surface lava), in February 1955 and January 1960.

A personal communication from the aerial photographer informs me that he, William Appleton, owns the land and he kindly gave permission to use the picture. He also added that recent thinking suggests that the crater and lake were formed only 350 years ago, rather than the 400 years, as traditionally suggested. There is apparently a proposal to build a geothermal power plant in the vicinity, although current thought is divided about whether the lake water is purely run-off or has a tidal connection (which could contravene groundwater pollution laws).

Tottering on the a’a lava at Kumukahi Lighthouse Point

A real disaster came to the small village of Kapoho, which was a place that lived by growing coffee, papayas and orchids. Early in 1960, there was a major eruption linked to Kilauea, from Puʻu Kapoho. It was one of a series of eruptions from the flank volcanoes of Kilauea. This was the last eruption in this immediate area and centred on a series of fissures just to the north of Kapoho and Green Lake. They are believed to have erupted from the same fissure system as Kapoho and are referred to as the Kapoho eruption, even though they didn’t come out of the actual Kapoho crater, where Green Lake is located. Lava spread eight or nine kilometres across Cape Kumukahi to the sea, extending the coast by an area of two square kilometres during 1960.

2 early view
Fig. 10. Dominating the town in the early days, the fire fountain produced masses of cinder, as well as lava.

When the summit eruption of Kilauea Iki ceased in December 1959, it was known that the magma chamber was more inflated than it had been at the start of the eruption, so it was no surprise when earthquake rumbles began further along the fault line of the East Rift Zone the following month, with over a thousand recorded on 12 January 1960. Overnight, large cracks opened in the ground in Pahoa and Kapoho towns, both of which are located on the rift line. By 8am, more large cracks opened up and lava fountains began along the main split about 300m from Kapoho, within the graben, rather than along the actual rift line.

Within half an hour, lava was spurting up to 30m high, along a fissure of just under a kilometre in length, with flows of pahoehoe and a’a lava flooding away from the fissure. Before long, cinder and spatter cones were being formed as the fountaining increased and started to concentrate in particular points, all about eight kilometres from the sea. The largest of these was Pu’u Laimana, just north of the Kapoho Cone.

There was a period of phreatomagmatic activity, when saltwater from Warm Springs Resort came into contact with the magma, and large quantities of fine black ash were produced by extremely powerful and spectacular outbursts. These clouds and their contents reached as far away as Oahu and even Kauai – a distance of over 535km.

The layers of ash were buried by later lava flows. A huge pahoehoe flow moved smoothly at around 3kph, carrying rafts of crusted lava – known as slag (as in the mining and smelting industries). Later lava fountains were up to 60m high with explosive bursts. A lot of flame was seen from burning ohio trees and methane in buried forest litter. Methane fires erupted from the ground behind photographers, who were then close to the leading edge, forcing speedy retreats. Before long, the rich coffee, orchid and papaya fields were entombed under lava and ash, and a record number of properties were destroyed in one evening (over a hundred). Legally, the fire brigade was obliged to try to stem every single fire, though their hoses were clearly having no effect whatsoever. The town was largely burned out, and then submerged under lava or giant heaps of cinder and ash. Bulldozed ridges and dykes were ignored by the lava, which opened new fissures further west.

3 powerful blasts of steam_1
Fig. 11. As the lava flowed through Warm Springs Resort, the contact with the underground water source produced powerful steam blasts and clouds reaching thousands of metres into the air.

Activity intensified and the fountains were estimated at 350m for several days, and reaching 450m at times. Vast quantities of lava flowed towards the coast. The mainly pahoehoe flow carried huge slabs of former crust at an estimated 3kph, in enormous amounts over a three-kilometre wide front.

The underside of the slabs is generally either an extremely sharp ‘pluck’ surface, where the near-solid lava has dragged loosely across earlier rock; or a ‘drip’ surface, where the underside has still been molten, but lifted, which allowed the liquid lava to drip downwards into the gap below. Either form is extremely difficult to walk on, when the slabs have been jumbled up and turned over, or left jammed on edge.

6. Molten flowing Slabby lava (2)
Fig. 12. Fast-moving lava flows tumbled over obstructions in lava-falls, carrying large amounts of surface ‘slag’, which are rafts of crust from earlier solidifying areas.

Eventually, the flow began to diminish in power and the great fountains were lessening and sending out ‘soggy bombs’ rather than great heights of spatter, turning red as the temperature dropped and the volume decreased. Within a day or two, the fountaining was finished, but it took another two weeks for all the lava movement to cease. The slowly continuing lava gradually became cooler and the surface was changing into an a’a flow of ‘broken and crumbly’ blocks and cinders, carried along by the slowed-down more fluid lava beneath. This slowly built up to a wall of a’a lava four and a half a metre high, and travelling at less than a half a kilometre an hour across the Kumukahi Cape.

The a’a flow is the one that finally covered most of the area, overrunning the coastguard and lighthouse stations. However, it skirted round the lighthouse itself, leaving it untouched with six metres to spare on three sides. This lava is very broken up a’a, with large and small blocks, and slabs and crust sections. And there, amongst it, stands the open girder-work of the lighthouse – untouched.

7. In the making IMG_4986
Fig. 13. Slab lava being formed from the rafts of crust that were carried along by the still molten lava beneath. My thanks to Darlene Cripps and Gary Sleik for this picture.

The whole surface of the a’a flow is very rough, but stable. The blocks and slabs cooled while still stuck together, as opposed to a mass of loose cindery material, which can be very unstable. If the face of an a’a flow becomes very solidly fixed, it holds back the continuing flow of molten lava behind it. This will cause upward pressure beneath the crusted surface. One way to release the pressure is for the lava to squeeze out between hard slabs and blocks. This can frequently produce an effect like toothpaste being squeezed out of a tube, as the lava exudes onto the surface and is pushed away. The surface flow will often retain the grooved nature of the gap through which it came, making a series of fluted lines along the surface.

Here and there among the tangled masses of a’a blocks and slabs, these flatter areas survive where the ‘toothpaste’ areas of flow have not broken up – presumable among the last active phases of the eruption. Like roadways through the broken jumble, they have longitudinal grooves that reflect the edges of the crack they were forced out of. Some of them also have ‘pressure pulse’ lines across them, which have something of the appearance of a roughly-ploughed field. They indicate that the lava was squeezed out in pulses, perhaps half a metre of forward movement across a nine-metre wide front. They occur at many points throughout the a’a flow, including in the vicinity of the lighthouse, and not just close to the original crater. This implies that the lava travelled a considerable distance under the main surface before it solidified, and then surfaced wherever it was able to force its way upwards.

Similar at first sight to the ‘toothpaste’ roadways are flat runs of lava, which were surface flows of pahoehoe lava, just at the stage where it ran out of strength and heat. However, the pahoehoe flows have curved wrinkles spreading across them and extending back along the edges towards the source of the lava; whereas the toothpaste flows have grooved lines along the length of them, except for the ‘pulse’ lines cutting across the flow, which are usually straight, rather than curved.

14. The Cape Kumukahi lighthouse IMG_1108a
Fig. 14. The lighthouse at Cape Kumukahi remained untouched.

Two additional features of this a’a flow are worthy of note. The first is the evidence of the under-surface continuing flows – the numerous lava tubes varying from a foot across to seven metres or so. As the source of lava diminished, so the level within these tubes dropped and left the roof perched above the new tube or cavern. The second feature is the sheer size of some of the slabs of crust. While most are a less than a metre across, broken by continual movement of the lava below, some are huge – as large as a three-storey house, but perhaps less than a metre thick. It is possible that one or two of these may be complete sections of the surface that began to topple into the sea during a cliff collapse (or ‘bench collapse’), when a whole area of the flow was undermined by waves.

Equally interesting for the petrologist or mineralogist is the detailed and varied nature of the rock hereabouts, within six metres of the parking. Some broken blocks reveal very dense, almost bubble-free interiors, probably indicating that hot lava burned out its gaseous content before setting hard. Others are filled with bubbles (vesicles) and are almost as light as pumice. These are sometimes stretched longitudinally in the direction of the flow. It is common here to find blocks containing both kinds of lava, often in layers. In such cases, the bubbles may have acted as a kind of ‘‘oil slick’’ that enabled one layer to slide across the other. It is a common feature of a’a blocks that the whole mass of the flow does not all move at the same speed. These layers of bubbles are one of the mechanisms for the differences in speed.

Three metres beyond the small car park at the lighthouse, many of the rocks contain olivine crystals in abundance. One hand-sized rock displayed more than 20 crystals, but they were only a few millimetres across, with the largest we found being almost a centimetre across. The presence of olivine crystals indicates that the magma originated deep in the Earth’s crust and quite possibly in the upper mantle. They are one of the first minerals to crystallise out of the base rock as it cools, so these indicate a fairly slow cooling process. Olivine – otherwise known as peridot and chrysolite – is magnesium iron silicate, which owes its green colour to the presence of nickel.

19. Inside a tube IMG_4985
Fig. 15. Hot molten lava lurking below the hard crusted surface at the time of the eruption. My thanks again to Darlene Cripps and Gary Sleik for this picture.

The aftermath of the eruption is plain to see. The town and its fields had almost entirely gone in six weeks of eruption. Ten square kilometres were buried under fresh lava and two square kilometres of new land extended into the sea. Around 130 million cubic metres of material were ejected, mostly lava, but also some pyroclastic material. It was the third largest eruption by Kilauea in the last century, after Mauna Ulu from 1969 to 1971 and Pu’u O’o-Kupaianaha from 1983 to the present.

Kapoho was never rebuilt. The area is a desert of a’a blocky and slab lava. Almost all the fields of orchids were ‘rescued’, with the plants being dug up before the lava reached them. One particular type of orchid survived – the bamboo orchid is now one of the most common plants among the lava flows and along the roadsides.

Even our 2014 visits didn’t do justice to this area – a’a lava is just as fascinating as the beauteous pahoehoe type. This lava field is basically a great expanse of shattered blocks and slabs, all tumbled and jumbled together. It is the result of the nature of the lava flow towards the end of an eruption, when the lava was cooling down.

23. Vesicular lava IMG_1067
Fig. 16. Some rocks contain great masses of bubbles. This one was very light and was the same structure all the way through.

There is a memoir of the event still available: Kapoho: Memoir of a Modern Pompeii (Paperback) by Frances H. Kakugawa. A professional photographer, Fred Rackle, filmed much of the eruption, and the superb result can be viewed at: https://www.youtube.com/watch?v=2BsIm7iodIs.  There is also further information at the CSAV site of Hilo University http://hilo.hawaii.edu/~csav/.

Visiting Lava Trees State Monument

This is a seven hectare park between Pahoa and Kapoho, on Highway 132. There is free admission in daylight hours, with a circular trail of about a kilometre. The pathway winds among numerous lava trees in a grass parkland and woodland setting that is like a fairy glen in the misty rain. The park is also well known for its living trees and the many different flowering bushes there.

What we hadn’t realised was that Hurricane Iselle had torn through Puna District on a August 2014, less than two months before our arrival and this area took the brunt of the strongest tropical cyclone that Hawaii has encountered in recorded history. The Kapoho (132) Road to Lava Trees State Monument had been blocked by hundreds of huge fallen trees. By October, the road had been cleared, but it seems that the modern living trees in the park hadn’t fared as well as the lava-created versions. When we arrived there, the park was still closed, so we didn’t manage to visit in 2014. It was fortunate that we had been on previous occasions, and found other superb examples of lava tree moulds in this district.

2. beautifully manicured IMG_4485
Fig. 17. The park is beautifully laid out and manicured.

A flow of tholeiitic basalt (containing less sodium than some other basalts) from Kilauea’s eastern rift zone swept through the ohia forest here in 1790. This was the most devastating eruption in Hawaii’s recorded history, since the one in which at least 80 Hawaiian warriors under Chief Keoua were suffocated by volcanic ash on their way to attack the senior chief, Kamehameha. This forest was drowned to a depth of up to three metres in places and perhaps as much again around a few trees.

It is thought that during the eruption, fissures opened up in the area and lava drained into them very rapidly, with the surface level dropping to less than half a metre high within hours of the initial flood. Some of these fissures are still visible around the park and there are notices warning of their hidden risks. It left behind a coating of lava on the standing trees about 15 to 30cm thick and on some that were already fallen, also. However, one mould in particular seems to show that the lava came through in several waves, with each staying long enough to coat the tree in a new layer. It appears that there were at least three such flows and quite likely a fourth.

It was a luxuriant rainforest before the lava arrived and the trees were wet. The dampness didn’t save them from the lava, but it took some of the heat out of the lava and briefly protected the bark with a cushion of steam. This gave the lava time to cool and settle around the tree, and not rapidly burn it away. Instead, the lava solidified in contact with the bark.

6. Dangerous cracks P1180402
Fig. 18. It really is dangerous to stray into the undergrowth – the fissures are very deep.

For a time, the forest must have had an extremely weird appearance – bare black-lava covering the ground, the trees dead and probably burned of their bark, now bare and bleached white in the sun. And each one with a jacket of black lava wrapped around it up to its waist. Eventually, the trees rotted away in the hot, wet climate, and left the empty moulds standing starkly above the lavascape. A few collapsed and either remained as horizontal tubes or smashed. Some of the still-standing ones have a perfect round hole down the centre, often with clear impressions of the original bark still imprinted around the internal part of the mould. Others are a joined mass of several trunks and small sprouting branches that were growing as a large clump, instead of a single trunk. Some that were already fallen were buried in lava and then rotted away, leaving horizontal tubes.

10. Trunk with vines IMG_4474
Fig. 19. The rounded interior of this mould appears to have several grooves down it – almost certainly where vines clung to the trunk – as many still do.

The Kazamura Lava Tube

A lava tube forms within a flow of lava, because the parts of the flow that cool first are the sides and these can create walls, which confine the flow’s direction. The flow may also crust over as it cools, perhaps in phases. Given the right timing and a supply of fresh magma, the lava will continue to flow beneath the new ceiling crust. It retains almost all of its heat and can resurface many kilometres away from its source at virtually the same temperature as when it entered. Such tubes are common on Big Island – 47 of them are said to be exposed on cliffs around the coast. More recently formed tubes in this area are separate and the volcano has not taken advantage of this system by re-occupying this route.

This particular tube stretches erratically for almost 30 miles (50km), but you refer to 68km below. Which is beneath the ground from volcano towards Hilo. There is an access point about five kilometres south of the Hilo to Volcano Hwy 11 road, between Kurtistown and Mountain View. The tube was formed during an eruption of Kilauea about 700 ago, as part of the Aila’ua flow. It was re-filled and drained intermittently during eruptions for probably 200 years afterwards.

Surveyors rate this as the world’s longest known continuous lava tube with a total surveyed length of 68km. It is a complex system with a main passage 40km long and other passages about 27km in length. Five separate complexes of mazes have been explored. It also lays claim to being the deepest cave in the USA, at over 1,000m below the surface in places, and has the greatest lava tube span from wall to wall at 21m in one place and almost as high. Throughout its length, there are more than 30 lava falls and cascades over three metres high, the highest being 13.7m. There are several scholarly articles about the cave on the Internet.

2. Colourful start IMG_1763ab
Fig. 20. Just within the entrance, the roof is coloured in reds, oranges and greens, through the mass of tree roots that penetrate from the ground above.

Tours are run by a small company called ‘Caverns of Fire’, and are by appointment only – but almost every day. The contact number is +1 (808)-217-2363. When we went, we were the only people on the visit. This was fine, as we could talk with the guide all the time and get personalised information from him. If you look on the Internet, you will see that this is a frequent occurrence, so don’t be shy about it.

We took the one-hour tour, which covered a superb range of features commonly seen in lava tubes and many that are unique to this one. The section of the tube that this explores is around 275m long. It was an upper overflow channel for the main tube, so it was periodically flooded and drained. The lava did not pour through here like a giant red river. Rather, it rose and fell more like the water in a bath. This calm and intermittent flow and flooding is what gave rise to the different features found here.

Waterproof jackets are recommended in case of seepage and long trousers in case of a trip. Armed with helmet, gloves and torches (the tube is not lighted), the entrance is just round the back of the office building among the undergrowth of the forest. It isn’t the fine bridge that appears on some websites, but a duck down over steps and rocks into the cavern, at a place where the roof once fell in.

8. Ceiling drips IMG_1714
Fig. 21. A further section of ceiling drips, which are larger than others, with some being 15cm long.

The first feature that is truly amazing is the wall and ceiling section just inside the entrance. The colours are phenomenal, and occur in patches of different shades and hues alongside each other. Long, fine tree roots grow down through the rock, in places quite densely and, in one instance, a root has grown through a hollow stalactite ‘straw’ and hangs out the bottom.

The floor varies from a smooth and beautifully coloured flat surface, where a lava surface gently solidified, to heaps of fallen roof rubble, with variations of lava formations, such as ropey flows, a ‘rose’ of dripped lava. There is also a circular section, where a radiating pattern is claimed to be the result of a single drop of falling lava causing ripples. However, in view of the viscosity of lava and its reluctance to transmit clear ripples, combined with the overlapping nature of many of the ‘ripples’, this seems unlikely.

Other sections of the floor are roughly grooved, indicating a flow suface that was moving as it crusted. Towards the end of the easily-accessible area, there is a double floor, with one flow crusted over to about 15cms. The lava beneath then fell in level by around 60cm and crusted over again. Both surfaces can clearly be seen. Other such changes in surface height are seen throughout the cave, forming benches at different levels along the walls and parts of the ceiling. These are often very clearly differentiated by colour differences, as well as the smoothness of their surfaces and the series of lava dribbles below them.

The ceiling, which is mostly a little above head height and therefore close enough to reveal its details, is festooned with a variety of formations. These are most obviously long drips, which have formed over a period during which the lava level rose and fell repeatedly. This caused the drips to be dipped and dipped again into the lava, each time adding a layer and making the drip thicker and longer. Some of the drips are distinctly bent – a mark of the direction of the slight current as the lava drained away.

Some areas of the ceiling are ‘sucked rather than plucked’, that is, when lava separates by being pulled apart, it generally produces a patch of sharp, needle-like spikes. However, here, the lava repeatedly pulled apart, as the level ebbed and flowed, and the sharp needles became more rounded with each coating left behind. The surfaces between them are somewhat reminiscent of the water-formed scalloped surfaces in limestone and ice caves. In places, they have joined together to create curtains, with an indication of the (very slow) direction of the flow.

12. Lava spires - Stalagmites are formed, too IMG_1653axx
Fig. 22. Where ceiling drips have been coming from the same spot for some time, these spatter spires are formed. The tallest one is less than 60cm high.

Where drips continued to fall from the ceiling and high parts of the walls, they formed patches of dribbles, like small spatter mounds on the floor and on the side benches. Unusually, these are often a different colour from the hanging stalagmites, as well as having a much rougher texture that formed as they solidified when they landed. In other places, lava straws have formed, hanging from the ceiling. These are hollow and were created in the same way as limestone ones – by water droplets evaporating on the lower tip and depositing a tiny amount of mineral each time.

I imagine that we have explored dozens of lava tubes in the past years, but this has to be the one that stands out for variety of form and colour.

There is also a three-hour ‘adventure’ tour into the main, lower passage, which is for the fit and young, seeking physical excitement. A couple we spoke with said it was excellent and many Internet reviews say the same. However, for old and unfit observers, the one-hour tour covers everything. Go to http://www.travelchannel.com/video/hawaiis-kilauea-caverns for a short video (2 minutes, 34 seconds) presented by the manager and guide, Steve Krucker. The Caverns of Fire’s own website (www.kilaueacavernsoffire.com/) has a short computer-animated sequence of how such a lava tube might have appeared during its active period. Many reviews justly use words such as amazing, unforgettable, unique and astonishing, when describing tours of this tube system.

Flights over the area’s different features

Over the years, we have had a number of flights over the craters and lava flows on Big Island, Hawaii. All have been good in some way – you see great fields of grey lava, hot flowing lava sometimes, with the opportunity to look down into the seething craters, and see the ocean entry lava-falls and the skylights through the crusted lava down into the molten lava flowing beneath.

However, flights by helicopter are expensive, often quite short and don’t always stick to where they said you were going. The windows are highly reflective and, if you get a middle seat in the back, you don’t get many photo opportunities. In addition, last year, the authorities seemed to be tightening up on where the helicopters can fly, so going in close over moving lava is generally not a likely option. We got $180 knocked off the price of a two-hour flight for two persons, because we attended a two-hour timeshare presentation (never again), but it still cost $300 each for a two-hour flight. One company guarantees a window seat, but, of course, this is more expensive.

3. into the pit P1180640
Fig. 23. Looking into a ‘skylight’ to see the hot lava beneath.

Flights may leave from the Hilo area or from Kailua-Kona. Which one is best depends on where you are staying and what you want to see. They usually include lots of waterfalls and the amazingly steep forested valleys of the northern coast. Try www.bluehawaiian.com/bigisland/ or www.safarihelicopters.com/big-island-helicopter-tours/. The photographs are all ones that I took on our last three visits, so you can judge if it might be worthwhile for you. However, we don’t all get the luxury of the US Geological Survey, with a privately chartered flight twice a week, and permission to go anywhere.

8. ocean entry explosion P1180600a
Fig. 24. Major steam and splatter explosions, when large amounts of lava hit the ocean.

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)

Leave a Reply

%d bloggers like this: