Posts Tagged With: pahoehoe

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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Comin’ Round the (Volcanic) Mountain

One of the enjoyments of the Big Island is the number of semi-rustic, idiosyncratic enclaves that harken, if not exactly “old Hawaii”, certainly off-the-beaten-path Hawaii. The small towns in Kohala are good examples of this, but another good place to experience it is in the southern reaches of the island. And those southern reaches are very southern indeed from an American geographical perspective: the southernmost point of the Big Island, accurately if unimaginatively named South Point, is at 18°55′ latitude the southernmost point in the U.S. (Key West, Florida also likes to boast this distinction, conveniently neglecting to include the important qualification that it is only the southernmost point in the continental U.S. It is in fact a good 5° further north than South Point.)

South Point is a pretty isolated, windswept point with little to recommend it except its geographical distinction. It is accessible by car by a road that branches south from the highway that circles the island. Not far from that branch point is the funky little town of Naalehu, which at 19°4′ latitude enjoys the distinction of being the southernmost town in the U.S. It is a sleepy, friendly village of 900 people that boasts the Hona Hau restaurant (“the southernmost restaurant in the US”), Shaka’s (“the southernmost bar in the U.S.”), and the Punalu’u Bakery (guess what). In fact, pretty much everything there — and there isn’t a lot — is the southernmost something in the U.S.

But it’s fun precisely because of its isolation. It enjoys its share of eccentric characters, like so many Hawaiian enclaves.

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This guy proudly informed me that he had suffered five traumatic head injuries.

The Punulu’u Bakery in particular is worth a visit, specializing as it does in one of the joys of Hawaiian cuisine: the malasada. Hawaii has a large ethnic Portuguese population, and the malasada is a traditional Portuguese treat whose description I will crib from Wikipedia for you:

A malasada (or malassada, from Portuguesemalassada” = “under-cooked”) (similar to filhós) is a Portuguese confection, made of egg-sized balls of yeast dough that are deep-fried in oil and coated with granulated sugar….  Traditional malasadas contain neither holes nor fillings, but some varieties of malasadas are filled with flavored cream or other fillings. Malasadas are eaten especially on Mardi Gras – the day before Ash Wednesday.

Punaluu-003It all sounds very exotic but I suppose that if I told you it was a jelly doughnut it would seem much less exciting. No matter. The Hawaiian version departs from the above description in two important ways: (1) the Hawaiians like them with fillings and icings, though the plain kind (just sugar) are also common. And (2) screw Mardi Gras, everybody eats them all the time, a genuine local tradition.

We pigged out on them: vanilla filling, chocolate filling, lilikoi (passion fruit) icing, etc., etc. Eight million empty calories and we loved every minute of it.

We continued our counterclockwise drive, rounding South Point and Naalehu and turning northeast towards Hawaii Volcanoes National Park. We’ll make another, more extensive trip there later that I will write about in due course, but our purpose yesterday had a narrow focus. As it happens, our son Gabriel is an atmospheric science postdoc at MIT and has been on the island for about three weeks with a research group, placing air sensors around the island to measure sulfur dioxide (SO2), and those sensors now needed to be picked up.

A number of the sensors were in a large lava field, many miles across, known as the Kau Desert. This lava has all been exuded by Kilauea Volcano, the centerpiece of the national park. It takes a number of forms depending on the temperature, gas content, and circumstances under which it was formed, but the two most common forms are a’a (pronounced ah-ah), which is sharp-edged, clinkery stuff, and pahoehoe (“pa-hoy-hoy”), which is ropy and relatively smooth and clearly evinces its original liquid form. The combination make for dramatic, seemingly extraterrestrial landscapes.

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But the desolation notwithstanding, life always finds a way. You can see some yellow flowers in the top picture, but the reigning champion of post-eruption hardiness is the ohi’a lehua plant, which is actually an evergreen related to the myrtle. Its bottlebrush-like red flowers are the first to gain a foothold in a new lava flow, hopeful little outposts of color in a sea of black and gray.

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O’hia flowers are very common sights on lava fields, especially at elevations above 1000′ (300 m) or so. They are only found in Hawaii, yet another reminder of the uniqueness of this place.

Categories: Hawaii | Tags: , , , , , , , , , | 3 Comments

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