A Land (VERY MUCH) in Motion

I wrote early on about these islands and why they exist. To recap, there is a “hot spot” in the earth’s mantle here in the mid-pacific. As the pacific plate moves over that hot spot, at the not-so-snail-like pace of 4 inches per year (your fingernail’s growth rate), volcanic islands are successively born.

Of the ~8 inhabited Hawaiian islands the oldest is about 6Myrs of age. But the complete geological record of volcanic islands produced by this hot spot extends way back in time, and actually shows many, many “islands” that lie (or did lie) in a great arc from the northwest (the very oldest) to the southeast (to the very newest). Many of those older masses are now but atolls, sand bars, or simply “seamounts”, disappearing back under the ocean from whence they came eons ago.

One of the very newest of the Hawaiian islands, the “Big Island” of this chain, called Hawai’i, is but a baby, at ~1Myrs old. (To be accurate, there is a new baby already born, called Lo’ihi, just southeast of Hawai’i, but it has not risen above sea level - - yet).














Being so young, Hawai’i still has quite active volcanic action: Mauna Loa and, especially, Kilauea (see the inset above, from the Hawaiian Volcano Observatory). The latter is the cause of the lava flows one can see right now. I should mention that these volcanoes and their lava flows are distinct in kind from the explosive, very destructive volcanoes that usually come to mind. The Hawaiian islands are comprised of great “shield” volcanoes. Take a look at Mauna Loa (“Long Mountain”), off in the great distance in the photo, with its gently sloping profile. Mauna Loa stretches so that it makes up about half the size of the Big Island. These mid-pacific volcanoes emit lava deficient in silicates and dissolved gases, and produce that lava at very high temperatures. Thus, the lavas flow well, and form gently sloping surfaces. That is not to say there have not been “great”, land-shakin’ events. And, of course, the path of the flowing lava has wreaked havoc on homes in its path over the years.

We spent our Holiday Season on Hawai’i, and traveled the island starting in its east, counterclockwise back to its southeast, ending in Volcanoes National Park (where Abby became a Junior Ranger). (Hawai’i is about the size of Connecticut, for you main-landers). All of the above wordy preamble is simply to say, “WOW”!

We found this island to contain the most dramatic, stark, beautiful and desolate landscapes we have seen. We did some horseback riding through an exquisite valley, some awesome snorkeling, and some kayaking. But, I’ll stick to the hikes through the active volcanic landscapes.

Our photos simply cannot do this justice. Too much depth is lost to appreciate the magnitude of much of what is pictured below. It was really amazing: There are few opportunities one has to walk on ground that was formed just three weeks ago!

Have you ever walked across a caldera? If you look back at that labeled photo, Kilauea Iki is down in the foreground. It erupted last in the late ‘50’s for a short time. The slightly sculpted hump in the middle distance (just above the tree branch) is Kilauea Iki’s now-defunct ash and cinder cone, Pu`u Pua`i (Gushing cone). That cone produced spectacular fountains. The flat expansive area below the cone is the Kilauea Iki caldera – a lava filled pool long ago.

Our first day’s hike was across this steaming caldera. You can appreciate the old lava bed up close, broken up due to uneven cooling and buckling. No photo can communicate the feeling one has walking across what was once a roiling lake of lava. To this day, steam vents pock-mark the caldera, and placing your hand near that steam can give you severe burns.

But, Kilauea Iki means “small” Kilauea, so what about Kilauea? In that first photo, behind and to the right of Pu`u Pua`i (the Gushing cone), is Kilauea. This is the most active volcano on earth. Its caldera is about 3 miles long x 1.5 miles wide. The sulfurous plume rising from its midst emanates from the pit crater within the Kilauea caldera, called Halema‘ uma’u (House of the ama’umu’u fern). Of course, Halema‘ uma’u is the current home of Pele, Goddess of Hawaiian volcanoes.

This pit crater is about a half mile in diameter (visible in the daylight photo), and the series of recent eruptions (started in 2008) created a vent that is a few hundred feet in diameter. At night, one is mesmerized by the eerie orange glow cast upwards on the sulfurous plume (photo). Yes … that glow comes from the pool of lava flowing “underground”, a few hundred feet below the Halem’uma’u vent.

Whither goest thou, lava?

Great shield volcanoes have action not only at their summits, but along zones, or rifts, leading away, usually in three symmetric directions - though, as the plate carrying the island moves northwest, the major active rift trails to the southwest of the original shield volcano. And, for Kilauea, this is so, as the current surfacing lava action comes along a zone that proceeds east / southeast away from the caldera itself. The action surfaces some 17 miles away from the Kilauea caldera, as the Puʻu ʻŌʻō vent has been emitting lava continuously since 1983. That lava has flowed in a number of episodes south to the sea. It is that flow on the way to the sea that has been a mix of devastation and creation. The lava has taken (evacuated) towns with it along the way.

Here is an example of a too-common site: the “end of the road”:












Another too-common site: someone has re-built a home on their “property”. This whole area was destroyed in the early ‘90’s, and the land, as you can easily see, is completely covered by thick lava flows. Sometime in 2004 or so, the Hawaiian government gave the owners permission to re-build – they owned the land; there was no longer an imminent flow threatening to re-take anything built on that property. So, a few “intrepid" folks re-built. Now, why one would do that, is anyone’s guess. I would like to have asked them (politely – really to understand).





Lets return to that flowing lava: Once the lava reaches the end of the island, it explodes as the hot lava meets the (cooler) sea. Those explosions create "Black Sand" beaches – made of fine, round-ish mini-pearls of exploded lava. The lava flow into the sea has also created several square miles of new coastline (some of it is unstable, and undergoes catastrophic crashes intermittently into the sea).













If we move back “inland” a bit, back to the end of that road, you can walk out on that new lava and see for yourself, as land is being created. You see the lava glow in tunnels within the relatively recent flows, just 20 yards from where you stand. And, at night this glow makes for another eerie site, as many little “lava eyes” look out at you from amongst the flows.













During the evening we were there, county workers went out at intervals beyond the warning tape, and sampled the lava – why, I really do not know; it was not clear it was for any scientific or safety purpose; cynically I think it was just to help put on a show. They bring you back “lava on a stick”, and wave it all just a little too closely to us in the crowd…..



















So, you take all this in, and then, as you are walking on that short path from the end of the road to the current lava viewing area, it dawns on you, and you really finally get it: This is land that is only a few weeks old.

To prove it, I opened our water bottle and poured some water down a crack. Immediately, I was “rewarded” with a burst of steam. The subsurface is quite hot, still, and will be for some time to come. Liz said she already knew that ground was hot, since our butts got quite warm as we were sitting on the lava watching. (Still, I was actually quite surprised by how vigorously / quickly the water was turned to steam – that is, how close to the surface the temperatures are well above boiling. I really almost got burned by that steam the first time I poured in the water).

"So what", you say. There are many things one could propose as a moral or lesson in all this. The lesson I got came from the stark contrasts I have seen over these few months. Liz had a vision about the order for us to take our trips to neighbor islands. Our family first spent time on Kauai, the oldest of the inhabited Hawaiian islands (that one can visit), at ~6Myrs. Lava flows, just like those we saw so clearly, and so freshly on the island of Hawai'i, also cover her older sister, Kauai. But, Kauai, the "Garden Isle", looks very different - superficially. Most of the flows have been covered by reclaiming flora (we did not even think about lava floes when we visited Kauai back in October). Much erosion has occurred over those eons of time to carve great valleys, and the volcanic calderas have died out long go (Kauai having "moved" ~180 miles away from the "hot spot"), and those great shield volcanoes have also now sunk under their own enormous weight, with their calderas now lying about at sea level.

These mid-pacific islands scream out at you that the earth is very old, that lands change, that the environment is mutable. The change is generally slow, but can sometimes be cataclysmic. You experience these islands and you feel these truths. Would that everyone who believes the earth to be only 10,000 years old could see this for themselves.