In a major discovery, university students have uncovered new truths about old stones. They studied how some of the old carvings in lava rocks found around Hawai’i may have been made. And it has led the enterprising students to a surprising application, and an exciting opportunity for our VC readers.

Background

Lava carvings are a long-established art form. There are an estimated 23,000 such petroglyphs (also known by the local name of kiʻi pōhaku, or lavaglyphs) within the Volcanoes National Park on Hawai’i. Almost any walk into the older lava flows is likely to find some. Many more can be found elsewhere across the islands of Hawai’i. The kiʻi pōhaku can be enormous: a connected series of lavaglyphs on a lava beach on Oahu stretches for over 30 meters. The carvings depict daily activities: fishing, canoeing, but there are also human figures, often carved like stickmen but some are more detailed even showing fingers. Did they immortalize their friends and families, or were these carved-on-demand by politicians, military leaders or local celebrities? Others depict abstract symbols where we can only guess their meaning. Perhaps all these images are the artists’ personal avatars!

It is an ancient art. The oldest carvings on Hawai’i are more than 600 years old – and remember that people have been present here only since 1200 or so. Recent ones can also be found, normally made by teenage tourists, which lack the artistry of the local first population. They are viewed as graffiti carvings, known locally (and denigratingly) as lavit’i’ti.

The art of Lavaglyphsis not unique to Hawai’i. Lava carvings are found in many places in the world. The Albuquerque Volcanic Field along the Rio Grande rift valley contains 24,000 of them, where some are thousands of years old. Papa Vaka, on the north coast of Rapa Nui (Easter Island) contains some of the most artistic lava carvings know. The star figure here shows a double-hulled canoe, 12 meters long, carved in the volcanic slabs, perhaps in memory of their original arrival on Rapa Nui. There are also many depictions of fishing, including an amazing carving of an octopus!

Traditionally, petroglyphs are stone carvings whilst petrographs are rock paintings. Lavaglyphs are petroglyphs which are carved in lava. This is by far the most common form around the Pacific. The advantages are that basaltic lava is very hard wearing and the lavaglyphs last a long time. Petroglyphs elsewhere in the world are often made in sandstone, which has the advantages of being much easier to carve (being a softer stone) but is prone to erosion: the images may not last as long.

The carvings were made using stone-age tools. These are generally assumed to have been stones of different sizes, with larger ones used as hammer stones or used sideways to rub off a top layer and prepare the surface by creating texture. Smaller stone chips were used to create the thin lines. The stones used for this must have been harder than the surface that is being worked on: it is a rule in geology that a hard object will scratch a softer one but not vice versa. It explains the preference the artists had for sandstone. But basaltic lava is rock-hard (it measures 6 on the Mohs scale, even above glass), and volcanic islands have little or no harder rock available – again by virtue (or otherwise) of their geology. So it is assumed that the Pacificians managed to use basalt to mark basalt, bypassing the geological rule by using stones of equal hardness. It is inefficient as the stones used as tools quickly lose their usefulness, but at least the supply of working stones was in effect inexhaustible. The continuous remaking especially of the chip stones would have been time consuming. Being a stone artist in the Stone Age could be hard work – which may explain the preference in Europe for stone paintings!

For Easter Island, it seems that much of the artistic work was done not on basalt, but on tuff. These are ash beds, whichever time have become compressed into rock: the tuff is much less hard than basaltic lava. Even the enormous Easter Island statues were created from this rock. But on Hawai’i, the lavaglyphs really are lavaglyphs, not ashglyphs.

New research

Research at the University of Hawai’i has now thrown new light on this problem. The scientists have shown that on the Big Island, the ages of the lava fields with the lavaglyphs are similar to that of the lavaglyphs themselves. This has given a whole new view on the mystery of how the hardness rule of geology was circumvented by the artists. Did they in fact do much of the carving while the lava was still hardening? It would explain how they managed to work the basalt with basalt. It wasn’t an option on Easter Island, where all volcanic activity long pre-dated any human presence, but then, they went for the tuff – for good reason.

Working with erupting lava was not safe but this would not have stopped the locals. Even nowadays, Hawai’i still has the reputation that when one of their volcanoes erupts, all the locals run towards it.

How did they do it in practice? The scientists propose that the ancient rock carvers would start work while the eruption was still on-going. They would find a place where lava was flowing below the crust. A heavy rock was used to crack the crust – this is known as the drop rock. The lava would come out of the crack and cover the surface in a thin layer. Now there were two different techniques. One was to wait until the thin lava was cool enough to work, and use sticks and mounted stones to work the pliable layer. The other was to lay out the desired pattern on the rock, and let the lava partially cover it. The stones could be removed afterwards, leaving the depressions. The sticks would carbonise, and would be easy to remove.

This discovery has completely changed our view of lava rock art. The artists were true lava sculptors. The precise technique is still being researched, but their lava skill clearly was unrivalled.

Lavaglyphs for the future

Two students of the University of Hawai’i have now taken this idea further. They tried to find out whether there were ways to shape lava without having to risk their life and limbs on the active lava flows. The idea came from recent work on levitation by sound, which makes particles move and create patterns by using focussed sound waves, as for instance discussed by Physics Girl on her episode on the Science of Shaping:

The technique works on sand on a plate, but (as explained very well by Physics Girl) can also create 3-d patterns in the air. The students first managed to apply the technique to create shapes out of honey. From there, at least in Hawai’i, it is a small step for studentkind to use it on liquid lava – something in plentiful recent supply in Kilauea during one of the frequent episodes! They wanted to recreate the Hawaiian lavaglyph patterns.

The students designed a sound-system box was build which can be programmed to create a variety of acoustic patterns. An ellipsoidal tray of acoustic horns (mounted separately) directed the sound waves at the lava flows, from a distance of 1 to several meters. It was used on the lava flows that reached the far end of the Kilauea caldera during the current series of episodes, where sufficient solid ground remained available to work safely.

The machine is called the Lavatrix™. It worked miracles! The machine adjusts the sound frequency to the required thickness of the pattern. The speed of sound in air is 330 m/s. The sound waves push the lava apart and create channels with a thickness of a quarter wavelength. A sound frequency of 10 kHz give a channel thickness of 1 cm. This produces indentations, which gives rise to negative shapes. Positive shapes can also be made. These require 5 times higher frequencies for the same resolution, as the speed of sound in lava is 5 times faster than in air. The Lavatrix™ has a button labelled ‘ultrasound’ which shifts the machine to this mode. The National Park Service was initially concerned about the effects this would have on the local bat population, but relented when shown that no bat ever gets this close to flowing lava.

The flat shapes formed out of the box with the first use of Lavatrix™: they looked perfect. The students discovered that they were also able to even create 3-d structures. This was done as in the old ways, by using the focussed sound wave to create narrow cracks in the lava crust, after which the rising lava could be shaped in the ‘ultrasound’ mode. The first attempt was open to improvement when the ultrasound failed, leaving a shapeless lava pile, as shown in photograph. (The person in front, slightly disappointed looking, is Dag Zale, one of the two students):

Later attempts showed that the pile could indeed be shaped by ultrasound – when it was working. The experiments reached an amazing accuracy. Take this simple 2-d pattern, created during episode 38:

or this complex 3-d structure, from episode 44:

The Lavatrix™️ has been proven to be able to replicate the ancient lavaglyphs. In fact, it has now been suggested that the ancient artists may have been aware of the technique, where several people with bone flutes would create the initial shape. This is currently hotly discussed among lava accousticians.

VolcanoCafe special offer

The two students have now decided that there might be a wider interest in this, and for them a way to work on their student debt. A company has been created, called the LavaLand™ Company, with as goal to create lava shapes (or lavatars) on demand during suitable volcanic episodes. They contacted VC with a proposal, and suggested that we work together on promoting Lavatrix™ creations. Our valued readers would jump at the chance to be the first to own a piece of fresh Kilauea lava, shaped like a reproduction of an ancient lavaglyph, or as an ornament for proud display, from the new LavaLand™ Company and its Lavatrix™!

It is therefore our pleasure to showcase a range of the objects that the two have already produced. All are created using the Lavatrix™ machine, and by replaying the program the objects can be recreated exactly. (Small texture differences may occur related to changes in composition of the lava, something the LavaLand™ Company has no control over.)

Personalised designs are also possible. If you would like to have your very own avatar in lava (a true lavatar), this is your chance! Prizes start at 50 USD, which includes the 1200% VC discount !

Below you can see a range of their current products. If you would like any other shape or sculpture, you will need to create a 3d printer file (only STL format is accepted – Lavatrix™ does not have the ability to create colour, and therefore OBJ files cannot be handled), submit the file to the LavaLand™ Company and they will contact you with a quotation. Do mention the VC discount code, available by emailing VC.
A lava letter of your choice It can be a perfect personal lavatar! Default size 10 inches but can be produced in larger or smaller sizes depending on eruption volume.

A Laa-Laa lava-tellytubby! Laa-Laa is a bundle of energy which goes with the lava flow, as described in the BBC lava-tellytubby review! An adorable soft-lava toy.

A chess queen, ruling the board! It will greatly enhance your skills at the game, as due to its weight and inertia this piece can only be captured by another Lavaqueen™, and any checkmate will be terminal! Other chess pieces are also available.

A Kilauean Lavasaurus Rex™! Not for the faint-hearted. Size is negotiable.

A park bench, full size. Can be ordered complete with engraved memorial text, ready for deployment in the wild.

A lavaphant to complement the lavasaurus!

For the adventurous: a Taj Laval™! Can be ordered in a range of sizes. Full size is possible but is best created in-situ.

Lavalangelo’s non-finito David (Currently on hold because of a copyright dispute)

Orders received on April 1 will get priority for the next Kilauea episode!

Order form

VolcanoCafe, 1 April 2026

“Those who can imagine anything, can create the impossible.” (Attributed to Alan Turing)