jen-luc versus the volcano

Too_cooljenlucThings have been a bit subdued at the cocktail party in part because Jen-Luc Piquant is tres desolee at the passing of Sir Edmund Hillary last week. She considers him a fellow adventurer-in-arms, you see, even though he made history by becoming the first to summit Mount Everest, while Jen-Luc has yet to merit a footnote in history for her myriad Cyber-exploits. It's a lot easier to summit a virtual Everest, for starters, so such feats are less impressive. But we also admire Hillary for his characteristic modesty — he never acted like a "celebrity" — and for spending 40 years raising funds for the Himalayan Trust, a nonprofit organization to benefit the Sherpas native to Nepal. (It was a Sherpa named Tenzing Norgay who guided Hillary to the Everest Summit. Tenzing succumbed to a lung infection back in 1986.) The Trust has built some 27 schools, 13 village health clinics, even rebuilding bridges, setting up drinking water systems, and providing scholarships to village youth. So the world is suddenly slightly less richer for Hillary's absence.

In defense of her honor as an adventurer, Jen-Luc reminded me that Mauna Kea, a volcano on Hawaii's Big Island, is, in fact, taller than Everest if one follows its base all the way to the floor of the Pacific Ocean. Not that either of us have summited Mauna Kea either. During my brief visit to Kona last month, I did get back on the Queen Kaahumanu Highway and make a day trip to the island's Volcanoes National Park to check out Kilauea, which might not be on the summit of Mauna Kea, but is still pretty close. In Jen-Luc's twisted reality, this constitutes a rugged adventure, when in fact, I pretty much just drove round the crater's rim, stopping periodically at the usual tourist spots: the steam vents, the Jagger Museum, and so forth. Since the only observable lava flow at the moment is only accessible by helicopter, the biggest hardship was the atrocious, highly changeable weather: it was damp and chilly  with occasional burst of rain. 

But it could have been dangerous, yesiree: the park is rife with warning signs about volcanic fumes, unexpected eruptions, cracks in the earth and the heat from lava fields, not to mention admonishments to "Watch for Nenes." (Nenes, crossword puzzle aficionados will tell you, are Hawaii's native species of goose.) Had the weather been better, and had I not had to get back to the airport in Kona to catch my flight home, I  might have opted to hike along the 150 miles of trail; there's a short four-mile trek, or, if one is feeling particularly energetic (and outfitted with the proper gear), it's possible to hike 19.6 miles to the summit of nearby Mauna Loa.

Volcanoes hold a special place in Hawaiian cultural history and mythology, and rightly so: the chain owes its very existence to the many eruptions over millions of years; the islands are basically the accumulation of lava flows. And Hawaii is still growing new islands and expanding old ones, thanks in large part to Kilauea, one of the world's most active volcanoes. Kilauea is also the sacred home of Pele, the Hawaiian goddess of fire (or volcanoes — the two seem to go hand in hand).  Hawaiian mythology tells of how Pele's father exiled her from her homeland (Tahiti) because she had a nasty temper and was prone to outbreaks of violence; apparently she was a bit of a prima donna, with a fondness for temper tantrums. Jen-Luc likes her already. Anyway, she left Tahiti in a canoe and a sympathetic brother guided her to the Hawaiian islands. But she did something to royally piss off her sister, Na-maka-o-Kaha'i, who followed Pele and flooded out every volcanic home Pele tried to build. (There's several versions of this legend, needless to say , but all amount to a series of pitched battles between warring sisters.) Eventually Pele was torn apart by her sister near Maui and local legend holds that her bones form a small hill called Ka-iwi-o-Pele.

Pele was luckier in death than most: she became a deity, eventually settling in Kilauea. Another pitched battle against the fertility god/rain god Kamapua'a — the lover's quarrel from hell, arising when the fickle Pele jilted him and he refused to go quietly –  is said to have led to the formation of the Kilauea summit's famed crater Halema'uma'u. It ended in a draw, with Pele keeping the Kona side and Kamapua taking the northeastern side. Pele can't get along with anyone, it seems, and the topology of Hawaii is all the richer for it.

I can't recall visiting any other place where the geology just seemed so dynamic; perhaps the presence of active volcanoes, constantly shifting the topology on much shorter time frames than one normally gets with geologic formations. For instance, about 90% of the surface of Kilauea is lava flows that are less than 1100 years old, and 70% of the surface is less than 600 years old. The most recent new formation in the Hawaiian Islands chain (well, relatively new) is Lo'ihi, a seamount and undersea volcano just off the southeast coast of the Big Island. It's already taller than Mount St. Helen's, even though its top is still 3200 feet below the surface; it last erupted in July 1996, forming several craters, including one called Pele's Pit. (That Pele, she has to have her name on everything.) Scientists are monitoring/studying the nascent volcano via manned submersibles and various recording instruments When Lo'ihi finally breaks through to the surface in, oh, a few tens of thousands of years, scientists will be able to witness the beginnings of life on its rocky surface firsthand.

Right now, the working theory is that a few million years ago, various spores, insects, seeds and spiders found their way to the nascent Hawaiian islands via wind and water currents. Only the hardiest survived. Frankly, I was surprised at how much vegetation seemed to thrive on the Big Island, considering it's entirely lava rock. It just so happens that lava is rich in minerals and nutrients that plants love, so a thin layer of soil can nonetheless support thriving crops of coffee beans, for example. (We stocked up on Kona coffee before heading home, oh yes.) The land proved just as nourishing for an astonishingly diverse range of species: apparently more than 90% of the flora and fauna in Hawaii can't be found any place else on earth. Sadly, many of them are now endangered; Hawaii has more endangered species per square mile than any other place on Earth. There's good news for its human inhabitants, though: the average projected life span of those born in Hawaii in 2000 is 79.8 years, longer than for residents of any other US state.

It's been said that Eskimos have many different words for "snow." Similarly, Hawaiians seem to have a different word for each type of lava. The main types are a'a (a favorite of Scrabble fans everywhere, and pictured below) and pahoehoe. Chemically, they're pretty similar, but pahoehoe is a smoother, ropy appearance, and is hotter and contains more gas, than a'a, which has a rougher surface made of broken lava blocks (clinker), and has a higher viscosity than pahoehoe.

Pahoehoe is also responsible for the creation of lava tubes, like the gigantic Thurston Lava Tube featured in the national park. (I gamely trudged along with the rest of the tourists to walk through the lava tube; it was eerie, and damp, but definitely worth the effort. Yeah, that's me, the intrepid adventurer. Celebrated rebel chef Anthony Bourdain suffered more during the taping of the new season of No Reservations for the Food Network.) Lava tubes form when flowing lava that's still pretty fluid cools on the upper surface and forms a crust, under which the rest of the lava continues to flow as a liquid (the crust serves as an excellent insulator). Over time, this forms a tunnel-like tube structure — think of a giant sewage pipe, only cleaner, and entirely natural. Once no fresh lava is flowing through, the conduit drains, making it safe for hordes of tourists to traipse through trying to take pictures in the dim light.

But lava comes in other forms as well. For instance, occasionally the many fiery fountains on the volcanoes spew lava into the air where it forms small droplets — poetically known as "Pele's tears" — thin sheets of flakes of volcanic glass (limu o Pele), or long thin strands of glassy volcanic filaments ("Pele's hair"). I saw some samples of Pele's hair in the Jagger Museum: they don't look anything like black hardened lava; they're babyfine golden strands bunched together in clumps that really do resemble hair. There's also pillow lava: the type that forms when lava emerges from an underwater volcanic vent, or when it flows into the ocean. You get another crusting effect when this happens, and the crust than cracks, oozing large blobs (pillows) of flowing lava that in turn hardens/forms a crust.

Nor are all eruptions created equal. Most of us think of Hollywood volcanic eruptions, with fiery lava and ash and whatnot spewing from the mouth over a short time period, when in fact, the current Kilauea eruption technically "began" in January 1983, and is still going on, producing the odd bit of lava flow here and there — in the 1980s, the lava fountains/flows could easily be seen from a car traveling along the highway, so it was known as the drive-by volcano. That's known as a non-explosive effusive eruption, according to Wikipedia. But there are also more short term explosive eruptions, and these are far more dangerous than the a'a and pahoehoe lava flows (which travel slowly enough to allow folks to get out of the way, although lava flows destroyed a couple of towns and a chunk of State Rte 130 in 1990). These explosive eruptions produce volcanic ash, hot gases, and hot dry rock fragments called tephra, rather than lava flows, ejected at very high speeds. It's basically a volcanic avalanche.

They're called pyroclastic flows, they're very hot, and very fast, and they are very, very nasty, usually destroying everything in their path, either from sheer size and force, or by their very hot temperatures, which tend to set any kind of combustible material aflame. People and animals are routinely killed by having the misfortune to be near a pyroelastic flow, often from burns or by inhaling the hot gas and ash. Apparently the stuff solidifies in one's chest after inhalation, so the victim slowly suffocates. If said victim gets really, really, lucky, perhaps s/he will be killed instantly by a large falling rock fragment before this happens. Mount St. Helen's gave rise to several pyroclastic flows during its May 18, 1980 eruption, and almost everyone has heard of the destruction of Pompeii in 79 AD. I always wondered why people didn't have time to get out of the way; clearly, I was thinking of the slower-moving lava flows, when in fact, Pompeii fell victim to a mother of a pyroclastic flow. The 1902 eruption of Mont Pelee in Martinique created a pyroclastic flow that killed almost 30,000 people and wiped out the village of St. Pierre.

Scientists seem to know quite a bit about volcanoes, but the mercurial Pele (to anthropomorphize a little) remains pretty fickle and unpredictable about just when she's going to blow her top. Which is where infrasound comes in. (Technically, I was in Hawaii visiting the University of Hawaii, Manoa's infrasound laboratory, headed up by Milton Garces.) Volcanoes generate lots of infrasonic rumblings, and those signals seem to get stronger just before an eruption — eg, Japan's Sakurajima volcano generated lots of infrasound signals when it erupted in 1998. In fact, the first infrasound ever recorded occurred in 1883 with the eruption of Krakatoa; barometers around the world recoded wild fluctuations in the atmosphere, much like an earthquake in the air. Comparing the waveforms with the paper records allowed researchers to determine the magnitude of the explosion.

These signals, alas, are faint enough that it's tough to differentiate them from other noise sources. Fortunately, we have computers now, and don't have to make this analysis by hand. But interpreting the signals remains a challenge. Scientists are getting better and better at reading Pele's multitude of moods; hopefully one day soon, we can use infrasonic signals to make better predictions about when a volcano blows.

 

3 thoughts on “jen-luc versus the volcano”

  1. They’re actually called pyroclastic, not pyroelastic, flows. If you follow the link it has the correct term.

  2. Ack! That’s what I get for late-night typing: tiny “c”s start to look like tiny “e”s. At least I was consistent in my mis-spelling. 🙂 It has now been corrected….

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