Lava, Actually

Kilauea is rightly famous for being both the most active and the safest volcano in the world. It is a so-called shield volcano for its gentle convex shape, formed that way both because of the composition of the lava and its more or less continuous flow. This nonetheless does not prevent the active regions from looking like a post-apocalyptic hellscape, or a parking lot the size of San Francisco after a nuclear bomb has gone off. Yesterday it looked like this:

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If you look carefully you can see the zombies eating the tourists in the distance.

This is essentially a broad, flat crater, technically called a caldera. It’s about 3 miles (5 km) across and is dotted with number of craters-within-the-crater. The largest of these is Halema’uma’u, a good half mile across and 300 ft (90 m) deep. You’ve got a glimpse of it on the horizon in the picture above, where the steam is rising. said steam being the vapor cloud from the molten lava lake sitting at the bottom. You used to be able to hike across the caldera up to the edge of Halema’uma’u, a practice that the National Park Service strongly discourages today because of the likelihood that you will die. So access is closed off. It is nonetheless possible to get closer from a different vantage point along the caldera rim, from where it looks like this:

Volcano-012 That’s still not close enough to see the lava lake, unfortunately, but if you stick around till after sunset you can see still see the orange glow from it. Or at least you can if the vantage point is not completely socked in with fog, which it was when we tried. Speaking of which, you will notice that both of the above photos seem a little hazy. That phenomenon is the aptly-named “vog”, which is short for “volcanic fog”, a witch’s brew of water vapor, sulfur dioxide, and assorted volcanic particulates, and which on a bad day can blanket the entire island. You need an occasional healthy rainstorm to clear the crud out of the atmosphere and get you those beautiful views that you see on postcards.

A good fraction of the southeast corner of the Big Island is taken up by Hawaii Volcanoes National Park, and a good part of that is taken up by one or another lava field. The fields are marked as having been laid down by one or another eruption, e.g., “November 1979 Lava Flow”. So you can collect all your favorites — “Ah, March 1972, that was a good one!” — though they pretty much all look like this:

Volcano-029Some of the lava fields are blacker than others — you can see that this one is kind of brownish — depending on the exact location and thus the gas content and mineral composition of a particular flow. There is not currently an active lava flow running down to the ocean, which when it happens affords the spectacular sight of the glowing 2000-degree stream falling into the sea and raising one hell of a steam cloud. When that does happen you can join up with a boat tour that sails along the coast and gets close enough to let the passengers see the show.   But alas, we won’t have that on this trip.

The caldera is at the summit of the mountain, at an elevation of 4000 ft (1200 m). It’s noticeably cooler there than at the coast, and much rainier than Kona as well. For those reasons, the vegetation at the higher elevations in the park is very different than elsewhere on the island. It is, in fact, very Jurassic World-y, with lots of ferns and cooler-weather plants.

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Plant and wildlife in the vicinity of Kilauea can be unique to an astonishing degree because of a combination of topography and evolution. As a wide river of lava flows down to the sea, the terrain may cause the flow to split and then rejoin further downhill, resulting in a small “island” of untouched land in the midst of the molten flow. The plants and small ground-dwelling fauna (mostly insects) are thus temporarily cut off from the rest of the world, and so they do what Charles Darwin told them to do: continue to adapt to their local environment, which may be as small  as a couple of football fields. Such a region is called a kipuka, and the Big Island is home to a number of them. Kipukas can be the home to species and sub-species that are found, not only nowhere outside of Hawaii, but nowhere outside the kipuka. How’s that for specialization?

I mentioned earlier that Kilauea is known as the safest volcano in the world, because its pattern of long-duration eruptions and the nature of its magma vents prevent explosive pressures from building up. However, Pele — the Hawaiian volcano goddess, not the soccer player — is not real big on predictability and although there have been no Mt-Saint-Helens- or Pinatubo-style eruptions, there have been some pretty violent events that have altered the landscape. One, in late 1959, wiped out a heavily forested area with 16 explosions and a rain of volcanic ash, lava, and related stuff that you do not want to be standing under.  The result is an area called Devastation Trail, which is, indeed, um, devastated.

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I mentioned in an earlier post that there are several types of lava, the two most common being a’a, which is the rough clinkery stuff, and pahohoe, which is ropy and relatively smooth. During an eruption a’a advances very slowly, at about a walking pace, a very, very hot wall that moves like an advancing glacier. Those glowing rivers that flow down to the sea are pahoehoe, and if the terrain is right then the top layer can cool and start to harden while the stuff underneath continues to flow. In that case you can end up with a hollow channel: a lava tube. The park has a famous one, Thurston Lava Tube, big enough for a crowd of people to walk through, as you can see below. The first image is the fern-lined entrance to the tube.

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Those things hanging down from the ceiling are not stalactites; this is not a limestone caved formed by water laying down mineral deposits. They are tree roots, o’hia lehua trees to be exact. The o’hia lehua trees with their bottle-brush red flowers are one of the first forms of life to reestablish itself after a lava flow scours the land, and as you can see they are more than a little tenacious. As indeed, you would have to be if your ambition is to thrive on lava.

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