Monday, November 26, 2012

Insights from the Other Side of Yesterday

“He climbed the Mount Pinatubu in exactly twenty-one tremendous leaps. When he had reached the top, he at once began to dig a big hole into the mountain. Big pieces of rock, mud, dust, and other things began to fall in the showers around the mountain. During all the while, he howled and howled so loudly that the earth shook ... The fire that escaped from his mouth became so thick and so hot that the pursuing party had to turn away.”
Mount Pinatubo on June 15, 1991.  From USGS / Cascade Volcano Observatory
Mount Pinatubo is a stratovolcano on Luzon Island in the Philippines, part of a volcanic chain along the Manila Trench where the Sunda Plate (southeast Asia) is being subducted under the Philippine Mobile Belt.  Pinatubo sits -- perhaps hides -- in the midst of heavily-vegetated non-volcanic mountains, and was known to few geologists prior to 1991.  Then on June 15, it exploded, producing the second largest terrestrial volcanic eruption of the century.  Compounding the disaster, Luzon was hit by Typhoon Yunya on the same day.
Snow-like deposits of rain-soaked ash and debris.  USGS photo (R.P. Hoblitt).
The immensity of the eruption was a horrible surprise, but it didn't come without warning. There had been many small earthquakes around Pinatubo, several steam explosions, and increasing emissions of sulfur dioxide gas during the preceding months.  In early June, the first magma reached the surface, as lava flows.  Then on June 12, gas-charged magma exploded from the volcano.  Dramatic eruptions continued for the next few days, but these were only Pinatubo's opening acts.  On June 15, truly cataclysmic activity commenced. Huge ash columns reached as high as 40 km, and avalanches of pyroclastic debris raced down the volcano's slopes at 70-80 kph, burning everything.  During the largest explosions, incandescent avalanches traveled as far as 16 km from the mountain.  Nineteen major eruptions were registered that day before recording stopped.

By the time things had quieted down several days later, more than a cubic mile (5 cubic km) of material had been ejected and Pinatubo had collapsed, forming a caldera 2.5 km across and over 600 m deep.  The high point of the rim -- and the mountain -- was 260 m lower than the original summit.
Pinatubo caldera.  Ash continued to vent from the floor through late June and July.  USGS photo (J. Mori).
“On the summit of the Pinatubu was the great hole, through which Bacobaco had passed, and from which smoke could be seen constantly coming out. This showed that although he was already quiet he was still full of anger, since fire continued to come from his mouth...”
Bacobaco -- “the terrible spirit of the sea, who makes the storms and the waves” -- loves deer meat.  He occasionally makes himself into a giant turtle and comes ashore to hunt. 
Pinatubo’s early warnings gave residents time to evacuate, saving at least 5000 lives (USGS 2005a), but much of the destruction came later when extensive deposits of volcanic debris were mobilized by monsoon rains.  For the next five years, lahars (volcanic debris flows) swept down the mountain's major drainages, completely destroying some towns, greatly damaging others.  Lahars dammed tributaries along the way, creating ponds and lakes.  Most impoundments subsequently overflowed, causing even greater destruction.  Losses caused by Pinatubo were estimated at a billion dollars (USA).  Over a million people were displaced.
Pinatubo lahars; from USGS 2005b.
“newly formed Mapanuepe Lake after sinking three villages in San Marcelino, Zambales, Philippines.” (1992)
One of the largest lahar impoundments still exists -- Mapanuepe Lake (above).  There's evidence of an older lake at this site as well, apparently destroyed by a “prehistoric” eruption of Pinatubo (Rodolfo and Umbal 2008).

“For three days the turtle continued to burrow itself, throwing rocks, mud, ashes, and thundering away all the time in [a] deafening roar.  At the end of the three days he stopped, and all was quiet again in the mountain.  But the lake, with its clear water was now filled with rocks, and mud covered everything.”

The aboriginal Ayta people were the ones hardest hit by Pinatubo’s eruptions and terrifying lahars.  Though they had no experience or memory of volcanism, the mountain’s name suggests that perhaps their ancestors had witnessed one of its brutal outbursts.  In the Ayta language, as well as in Tagalog (Filipino), “tubo” refers to growth, and “pinatubo” can be interpreted as “made to grow” or “allowed to grow” (Rodolfo and Umbal 2008).

Prior to the 1991 eruption, Pinatubo's violent past was a secret.  It had kept its fierce personality well-hidden for as long as anyone could remember ... or so people thought.  As it turned out, there had been a report of the hideous monster-nature of Pinatubo, quite a graphic account actually, but it came from the other side of yesterday, a source given little credence in today’s world.

The Pohnpeian people of Micronesia have a term “keilahn aio” which translates to “the other side of yesterday” (Sacks 1997).  It refers to times and events now known only as legend -- things that happened far back, beyond the reach of history.  These things may be myth and legend now, but perhaps they also are remnants of actual events.  Perhaps they are like the memories of early childhood, with little detail beyond a few vivid images.

In 1915, before any geologist knew of the volcanic nature of Pinatubo, J.N. Rodriquez collected and transcribed The origin of Pinatubu volcano (a Negrito myth) from an Ayta storyteller (Rodolfo and Umbal 2008).  Many years ago, Bacobaco, the evil spirit of the seas, had again morphed into a giant turtle and come ashore to hunt deer, his favorite food.  The Spirit Hunters were angry that he was back, and their king, Aglao, consulted with Wasi, the spirit of the wind, as to how to kill the monster, covered as he was with a giant shield on his back.  Wasi whispered to him, “Why don't you ask Blit, my brother, to help you?  He is the only one capable of killing Bacobaco, for if he hits him with the tip of his tail or a toe of one of his feet, it will kill Bacobaco.”

Blit, Aglao and the other Spirit Hunters pursued the giant turtle, shooting arrows at him.  As recounted above, Bacobaco jumped into the lake at the foot of Pinatubo, but the water was so clear that it afforded no protection.  He then bounded to the summit and started to dig -- throwing debris into the sky, obliterating the lake, and breathing fire and smoke from the giant hole he had made for himself at the top of the mountain.


When the Ayta had finished telling the story of Pinatubo, he added his own thoughts:
“But now, you do not see smoke coming out of the Pinatubo mountain ... and many believe that the terrible monster is already dead; but I think that he is just resting after his exertions, and that someday he will surely come out of his hiding place again”
The man was right -- Bacobaco emerged from his hiding place just 76 years later.

Bacobaco came out of hiding on June 12, 1991.  This early eruption was spectacular, but was nothing compared to the climactic explosions that came three days later.  View from Clark Air Force Base.

Sources (in addition to links in post)

Illustrations of Bacobaco were created with designs from Free Tattoo Designs.

ABS-CBN Broadcasting Corporation.  1996.  Pinatubo Volcano “The Sleeping Giant Awakens”  http://park.org/Philippines/pinatubo/index.html

Oppenheimer, C.  2011.  Eruptions that shook the world.  Cambridge Univ. Press.

Rodolfo, K.S. and Umbal, J.V.  2008.  A prehistoric lahar-dammed lake and eruption of Mount Pinatubo described in a Philippine aborigine legend.  J. Volcanology & Geothermal Res. 176:432-437.

Sacks, O.  1997.  The Island of the Colorblind.  NY: Alfred A. Knopf.

US Geological Survey.  2005a.  The Cataclysmic 1991 Eruption of Mount Pinatubo, Philippines.  USGS Fact Sheet 113-97.  http://pubs.usgs.gov/fs/1997/fs113-97/

US Geological Survey.  2005b.  Lahars of Mount Pinatubo, Philippines.  USGS Fact Sheet 114-97.  Online Version 1.1  http://pubs.usgs.gov/fs/1997/fs114-97/

Friday, November 23, 2012

thanks

Thanksgiving is a time to stop and appreciate the basic things that I sometimes take for granted -- family and friends, good health, enough to eat, a warm safe place to sleep.  But there's something else I’m especially grateful for too -- all those extra special things that Nature provides -- like beauty, fascination, awe, mystery, always something around the corner, something new, something different, or a different way of looking at familiar things.
Bur oak leaves cover the trail.
Contemplation of nature makes my life so much richer and enjoyable ... and is even a source of sanity at times.
Young ponderosa pine dusted with snow and sunshine.
“After you have exhausted what there is in business, politics, conviviality, and so on - have found that none of these finally satisfy, or permanently wear - what remains? Nature remains."  Walt Whitman
Ponderosa pine on Dakota sandstone.
"And this, our life, exempt from public haunt, finds tongues in trees, books in the running brooks, sermons in stones, and good in everything."  William Shakespeare
Late fall in the northern Black Hills.
Devils Tower on Thanksgiving day.

Wednesday, November 21, 2012

Wonder of the Week: what’s that tapping?

On one Friday morning early, as I pondered weak and weary over many a quaint and curious volume of forgotten lore [15-year old project reports] -- while I nodded, nearly napping, suddenly there came a tapping, as of someone gently rapping, rapping at my kitchen door?  Maybe ... I wasn’t sure.

I knew it wasn’t a raven, they don’t live here.  Perhaps it was one of the many crows that hang out in our neighborhood.
American crows, photo(s) from Wikimedia Commons.
Vainly I had tried to borrow from these reports surcease of sorrow ... but cessation wasn’t happening, and that insistent rhythmic tapping didn’t help my mood at all.  Presently my soul grew stronger; hesitating then no longer, here I opened wide the door.  Long I stood in sunlight wondering, soon I heard again a tapping somewhat louder than before.  “Surely,” said I, “surely that is -- something at my window lattice; let me see, then, what thereat is, and this mystery explore.”
It was neither crow nor raven, but a bird who had found haven, drumming in the sun -- and nothing more.  And the bird was still beguiling all my stressed soul into smiling, so I went inside and got my camera.

The beguiling bird stayed another five minutes or so, continuing to drill into the east wall of my house.  It was a hairy woodpecker.
I guess I should have been concerned, but given that the usual birds in my yard are house sparrows, house finches, European starlings and an occasional rock pigeon, I was happy to have this visitor.  After he left, I took a closer look at the object of his attention -- a vertical slot in a wooden shake.  I doubt he created it himself, but there must have been something yummy in there prompting him to enlarge it a bit.
Back into the study turning, all my soul within me burning, again I read those pages -- though their answer little meaning, little relevancy bore.   Then upon the cushion sinking, I betook myself to thinking:  “This is just a store of ink -- and nothing more.”
The trials and tribulations of research.

Lyrical language in this post by, or inspired by, Edgar Allen Poe (The Raven, American Review, February 1845, 1:143-145).  Engravings by Gustave Doré, modified slightly.

Monday, November 19, 2012

Mighty Limber Pine

We look up to trees ... not just the tall ones, but also (or especially) those that represent the more noble aspects of human nature.  We see in them traits we aspire to ourselves. They are role models.
“... even more I revere them when they stand alone. They are like lonely persons. Not like hermits who have stolen away out of some weakness, but like great, solitary men, like Beethoven and Nietzsche. In their highest boughs the world rustles, their roots rest in infinity; but they do not lose themselves there, they struggle with all the force of their lives for one thing only: to fulfill themselves according to their own laws, to build up their own form, to represent themselves.”  Hermann Hesse, Bäume. Betrachtungen und Gedichte (Trees. Reflections and Poems)



Many people, maybe most, seem to have an instinctive reaction to the great size, strength and perseverance of trees.  Trees spark admiration, awe, contemplation.  We designate parks to protect them, and take vacations to see them, trying to capture with our cameras the things about therm that so inspire us.


Left:  Giant sequoia, Sequoiadendron giganteum. "Clothespin Tree" at Yosemite National Park.  Photo from Bradluke22.




Thirty years ago, we were hiking through incense cedars and white firs in Sequoia National Park when we rounded a corner and came “face-to-face” with the massive trunks of several giant sequoias.  I was stunned by their size, it was beyond anything I had expected.  They seemed other-worldly, primeval.  We had no camera, so we stayed for awhile, hoping to fix in our minds those feelings of awe so we could take them home with us!  Do I still have them?  ... yes, I think so.  They're probably deeply buried, but I'm sure they must affect me when the moment is right.

I was equally stunned when I met up with ancient bristlecone pines (Pinus longaeva).  They grow on arid windy slopes at 10,000 ft elevation for thousands of years, adding just a centimeter of girth per century.  The old ones lack the size and symmetry of stereotypical "mighty" or "noble" trees, but the beauty of their forms is astounding.
This bristlecone  is mostly dead, having lost main shoots and branches to wind, erosion and snow.  But it carries on, bent and twisted, with just a narrow strip of living bark, still producing viable seed -- the embodiment of perseverance and adaptation in the face of adversity.
“... it is natural to feel we might learn wisdom from them, to haunt about them with the idea that if we could only read their silent riddle rightly we should learn some secret vital to our own lives ..."  Kim Taplin, Tongues in Trees
Here's another tree I find impressive -- a sizable limber pine growing out of a slot in a granite outcrop.  Its home is hospitable in some ways.  Water runs off rocks into the slot, organic debris accumulates.  But the crevice is four to five feet deep and little sunlight reaches the bottom.  The pine must have started life protected but shaded, and buried each winter in snow that was slow to melt in spring.  How much was it able to grow each year, and what happened when finally it emerged into the sun?  Did it take off on a growth spurt lasting years?

Another problem -- there’s only so much space in the crevice.  The tree has done pretty well even so.  At breast height, it’s 11 feet in circumference, 3.5 ft in diameter, but the trunk isn't round ... in fact it's rather squashed.  The tree leans to the south against one of the rock walls, with its bark missing (orange patch below).  Was it aiming for more sunlight by growing southward?  Or did it bend under a load of snow, back in the days of its youth?
The limber pine has grown over the rock wall in the lower right corner of the photo.
Limber pine, Pinus flexilis.  NPS photo.
Which brings us to limber pines as role models.  They’re called “limber” for a reason -- their flexibility.  A few days ago, I came across a dead tree that had recently fallen, bringing down with it a young limber pine about six inches in diameter.  Amazingly, the limber pine hadn’t snapped.  It was bent at a 90º angle less than a foot above the ground, with no obvious damage to the trunk.

Another name for this pine is "limbertwig" -- in fact, longer twigs can be tied into knots.  This suppleness allows them to dance exuberantly in the wind.  Might we be inspired to do the same?
"A tree that bends is a tree that lives ... pride'll break a guy, but give-and-take is a dance.  So let's dance!"  E.B. Wooflinski
video
Limbertwig shadows dancing on granite while the wind sings. 



Limber pine is widespread in western North America.  I found many sources on the web that mistakenly characterize it as subalpine.  It occurs across a wide range of elevations, more so than any other tree in the central Rocky Mountains, from tree line to the margins of low-elevation grasslands.  For comprehensive information, see Pinus flexilis in the Fire Effects Information System.  Map courtesy USGS.
An old limber pine at treeline, White Mountains (southeast California).
My limber pine (above) grows at about 8000 feet in the Laramie Mountains of southeast Wyoming, at least a thousand feet below the subalpine zone.  The main shoot is dead, but the tree keeps growing anyway.  I really like this gnarled old pine in granite.  I considered following it, but I suspect it’s inaccessible much of the year due to snow, so I chose a weeping birch instead.  But now, on second thought, I think I will follow them both!
"The pine tree seems to listen, the fir tree to wait -- and both without impatience -- they give no thought to the little people beneath them devoured by their impatience and their curiosity."  Friedrich Nietzsche
I'm Following a Tree
Are You?

Tree-following is hosted by Lucy at Loose and Leafy.

More tree wisdom and quotes can be found at The Quote Garden and the Garden Digest.

Thursday, November 15, 2012

Wonder of the Week: ice on the river (Jack is back)

We all complain when winter arrives.  We know it will be long, with short, cold, windy days, bad roads, big heating bills.  But winter brings nice things too, like exquisite ice sculptures left by Jack Frost each night.
A few days ago the first real ice of the season appeared along the margins of the river, so I took a closer look.  Ice patterns are fascinating, engrossing, and there's always something novel somewhere.  This time I found little white ice rings, clear in the center.  An hour later I returned with my camera ... but of course they were gone.
Sort of.  I found these instead.  Maybe the river had come up a little and filled the rings with water.

I kept looking for rings.  No luck, but I found other artwork that was just as intriguing, for example in ice build-up behind a log anchored in the river for fish.
A closer view:
Some ice chunks were nicely arranged on a rock, by ... ?
Then I came upon zig-zag ice.
And finally -- an ice ring!, surviving in the shade of the riverbank (ca 1 cm across).

There were some pretty cool moving objects too, like the shimmering watery blob below, slowly making its way through the ice.  All in all, it was a minor but very enjoyable exhibition, a nice way to start this year's winter art series.

video



All ice art courtesy Jack Frost.
From Central Park in Winter by Thomas Nast, 1864.

Monday, November 12, 2012

There's a hole in the ground (geology is destiny)

Until the mid 1800s, herds of bison grazed the large rolling grasslands of the Red Valley in the northern Black Hills.  They were there because of lush nutritious grasses, which were there because of deep fine-textured soils derived from soft easily-eroded red rocks of the Spearfish Formation.  Grasslands extended for miles and bison came in droves.  But there was danger in the grass.  In addition to creating grasslands, geology also had ensured that underground caverns would form and that the land above would collapse to make sinkholes.  It was the destiny of some 20,000 bison to end up in a single sinkhole, a hidden trap in the grass.
Bird’s eye view of the Black Hills to illustrate the geological structure” from the 1875 Newton - Jenney expedition.  Labels added; click image for a better view of the Red Valley (and the birds).
Take a look at the Black Hills from the air and you'll notice an obvious concentric pattern to the topography, the result of differential erosion after the Hills were uplifted.  Harder, more resistant rocks stand high, like the granite and limestone in the central part, and sandstone in the outer rim.  In between is the Red Valley or Racetrack, eroded into soft siltstones of the Permo-Triassic Spearfish Formation (equivalent to the Chugwater Formation outside the Black Hills).
Badlands carved by the Belle Fourche River at Devils Tower, Wyoming.  These redbeds started out as sediment deposited in a shallow sea some 250 million years ago.
Red Butte (could you have guessed?) in the Red Valley north of Newcastle, Wyoming.  Soft redbeds are protected from erosion by a resistant cap of gypsum (Jurassic Gypsum Springs Formation).
Redbeds, white gypsum, green soapweed yucca (Yucca glauca).
The Spearfish Formation also includes layers of gypsum among the redbeds, and it is because of the gypsum that there are sinkholes.  There are artesian aquifers under much of the area, and water readily flows up through fractures in deeper strata.  If the water crosses a gypsum layer, it dissolves the gypsum, sometimes enough to form caverns. The ground above may then collapse.  Sinkholes are common in the Red Valley, and new ones continue to form.  When a piece of ground collapsed in 1985, local ranchers heard rushing water just below the surface, flowing through a cavern extending beyond the range of their flashlights.  They had found more evidence that at least some of the sinkholes in the Red Valley were created by dissolution of shallow gypsum.
Ground water under pressure rises along fractures.  If a gypsum layer is encountered, it can be dissolved to form caverns.   The ground above may then collapse to make sinkholes.  From Epstein et al. 2005 (click to view).
Model of the geology of sinkholes; fainter colors lower middle are my reflected shirt.
From Vore Buffalo Jump Visitor Center.
The Red Valley is an easy route across the northern Black Hills, and has been used as such for a long time -- by large migratory animals like elk, bison and probably Pleistocene mammals in the day, by American Indians, then trappers and traders, and now by tourists and truckers on Interstate 90.  I-90 follows the Red Valley from Sundance, Wyoming, east to Rapid City, South Dakota, en route from Seattle to Boston (above and below).
I-90 crosses the northern Black Hills by way of the Red Valley.  Red soils are visible in the broad valley bottom northeast and south of Sundance.  It's much narrower on the east side of the Hills.  From ArcGIS online. 
Original plans for I-90 had the highway crossing part of the Vore Ranch west of Beulah, Wyoming.  The east-bound lane was to pass over a fairly large sinkhole that would have to be filled and compacted.  When engineers drilled into it to assess the feasibility of the route, almost immediately they hit an amazing deposit of bones and American Indian artifacts.  The highway route was shifted south, and excavation of the sinkhole began.





Left:  Preliminary excavations in the early 1970s revealed bones throughout the sinkhole, which is about 200 feet across.  It is estimated to contain the remains of 20,000 bison, and thousands of stone arrow points and other tools.  Photo from Vore Buffalo Jump website.
The dig in 2012.  This section is labeled for the benefit of visitors.
Driving buffalo over the edge; from Wyoming Tales and Trails, no source given.
The Vore sinkhole is about 40 feet deep, with steep walls -- an unseen and fatal hazard for a running bison or stampeding herd, a perfect trap.  For at least 400 years, from 1300 to 1700 (AD), American Indians drove bison into it.  The panicked animals probably were completely unaware of the hole in the ground until they plunged over the edge.  Any that didn't die outright from the fall were finished off by hunters.  The animals were then butchered at the site.

The deposit of accumulated bones and tools in the bottom of the Vore sinkhole is almost 20 feet thick, with 22 distinct levels.  Fortunately for archeologists, sediment washed in every year, and these annual layers (varves) can be used to date individual jumps.  “It’s not just a pile of bones, it’s a history book” (Gene Gade, VBJ Foundation).



Tribes that probably used this buffalo jump include the Shoshone, Crow, Cheyenne, and Plains Apaches and Kiowa.



Right and below:  map painted on buffalo hide, showing geography and American Indian tribes of the Great Plains, from the VBJ Visitor Center.  The hide was donated by John Flocchini of the Durham Buffalo Ranch in Wright, Wyoming.

Gene A. is an interpreter at the Vore Buffalo Jump,
and has been involved with the project for many years.

The importance of the Vore buffalo jump as a cultural site was recognized early on.  It was designated a National Historic Place in 1973, and in 1989, the Vore family generously donated 8.25 acres for research and education.  The site now is owned and managed by the non-profit Vore Buffalo Jump Foundation.  Research continues, and educational facilities and tours are available at the site.  A small interpretive center on the rim of the sinkhole welcomes visitors.  A large building in the bottom protects the excavation, which is open to the public.  The entrance fee is $5 per person, with a maximum of $10 per family (2012).

The VBJ Foundation is small but very active.  Contributions of any amount are appreciated; annual membership is $25.
The building over the dig was completed in 2010.
The Vore Buffalo Jump is located just north of I-90 between Sundance and Beulah in northeast Wyoming.  See the VBJF website for detailed directions.  It is open from 8 am to 6 pm from June 1 through Labor Day (confirm here), and off-season tours can be arranged.  Despite its rural location, visitation is respectable -- some 10,000 people stopped in at the site in 2010.
Aerial photo from GoogleEarth via the VBJ Foundation.
American bison cantering (you may have to give him a prod with your cursor to get him to move).  From photographs by Eadweard Muybridge; animation 2006.
Note:  American bison (Bison bison) are more often called "buffalo", probably because French fur traders called them "bœufs", meaning bullock or ox.  But the American critter isn’t a true buffalo.  It's more closely related to the wisent (European bison).


More Information

Watch a short video produced by the University of Wyoming Cooperative Extension Office for information and views of the Red Valley, the Vore sinkhole and the dig.

The Vore Buffalo Jump Foundation website is a good source of information on the archeology of the site.  There also is a short article about the geology of the sinkhole.

Epstein, J.B. et al.  2005.  Field Trip Guide 2. Karst features of the northern Black Hills, South  Dakota and Wyoming, Karst Interest Group workshop.  in USGS Karst Interest Group Proceedings, Rapid City, South Dakota.  USGS Sci. Inv. Rep. 2005-5160.  Available as multiple PDFs at: http://pubs.usgs.gov/sir/2005/5160/PDF.htm  Table of Contents here:  http://pubs.usgs.gov/sir/2005/5160/PDF/sir2005-5160part1.pdf

Kornfeld, M. and Reher, C.A.  1996.  12,000 years of hunting and gathering in northeast Wyoming: an archaeological overview of northeast Wyoming,  Tech. Rep. No. 10, Department of Anthropology, University of Wyoming.

Reher, C.A. and Frison, G.C.  1980.  The Vore Site, 48CK302, a stratified buffalo jump in the Wyoming Black Hills.  Plains Anthropologist  25:1-153.