Sierra Negra

Beez Neez now Chy Whella
Big Bear and Pepe Millard
Tue 14 May 2013 22:47
Sierra Negra




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The trail or should I say trial up. Al does his best impression of a tourist and Richard our guide of Fidel Castro with the help of a lot of moss.


Bear wanted to see the Sierra Negra, so being his birthday week he could choose and I had to smile sweetly. It’s only a ten and a bit mile walk. Super, yes dear, cannot wait dear, paint a fake smile on Pepe’s face. On the quayside at seven thirty, we were met by a taxi and Richard the National Park guide and off we went with Al (Irie II), Arjan (Dutch) and his wife Mya (Bulgarian) on their yacht Skye from Sag Harbour, New York. This lovely, patient, young couple politely laughed when you-know-who renamed it Shag Harbour. Do try to be good Big Bear. Half an hour later we were dropped off, packed lunch in hand, at the start of the trail up to the caldera. Sierra Negra (Black Mountain) is a large shield volcano at the south eastern end of Isabela Island that rises to an altitude of three thousand two hundred feet. It coalesces with the volcanoes Cerro Azul to the west and Alcedo to the north.



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The group take in the amazing scenery, Smiler and the crater edge.


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Geology: The Sierra Negra like the other volcanoes on Isabela is believed to have been created from a mantle plume which has created the hotspot. The age of Sierra Negra and the other volcanoes on Isabela is hard to determine as they are in a north-south line to the east of the hotspot, which is believed to be under Fernandina volcano, and the Nazca plate is moving east. This puts the volcanoes perpendicular to the hotspot. The surface of Sierra Negra and its neighbouring volcanoes are also covered by young lavas, adding to the difficulty of aging them. An estimate based on volume (one hundred and forty cubic miles) and eruption rates suggest that Sierra Negra is approximately five hundred and thirty five thousand years old.

The morphology of Sierra Negra is the upturned soup bowl shape of the other Isabela volcanoes, however it does not have the steep sloping sides that are on others. Instead the slope goes from approximately two degrees at its base and although increasing, averages only five degrees. The volcano has the largest caldera of all of the Galapagos volcanoes, with dimensions of four and a half by five point eight miles, with the long axis being south west to north east. The caldera is also the shallowest of the Isabela volcanoes at only three hundred feet. The caldera is structurally complex with a eight and a half mile long ridge within it. A large fumarolic area, Azufre, lies between this ridge and the western caldera wall. This fumarolic area is one of the locations where terrestrial sulphur flows have been identified, this is associated with the melting of sulphur deposits.



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 Caldera of Sierra Negra – the second biggest in the world.



The volcano is one of the most active in the Galapagos, with the last eruption starting on the 22nd of October 2005 lasting eight days. This eruption is estimated to have produced 1.5x108 m3 or loads of lava. Despite the GPS monitoring on Sierra Negra there was no advance warning of the eruption. There had been expansion of the caldera floor since 1992 but no short term deformational signal was noted before the eruption. Contraction continued through the nine day eruption before starting again immediately after the eruption ended.

Other eruptions occurred in 1911, 1948, 1953, 1954, 1957, 1963, and 1979. Eruptions in earlier years are not precisely known.


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We walked further, in fact as far as the tiny people in the picture, the itsy-bitsy ones looking out over Elizabeth Bay. That’ll be the ones just below the clouds. I have never, ever walked so far without having serious sponsorship promises on many, many sheets of paper. Yes dear. Don’t you yes dear me.......


Have you ever seen a flaccid flip-flop aimed with such feebleness.

Bear has.

Hobble Bear, Hobble (actually this was Bears first time in trainers since he lost his big toe nail in Tikal – oh my today there is so going to be a full blown repeat, I feel it in my water) ((I think he has a penchant for only having nine toe nails.....................)).



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The scenery changed to barren volcanic landscape.


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The shapes and colours were quite something. Just pictures follow, I’m way too tired and things are definitely complaining, chest pain, OH before I go on Bear suddenly mentioned angina, if only I had the strength to swing my camera round the back of his head. Then on the way back the right plantar fasciitis felt like a boiling hot marble in my flip-flop, the right ankle....well the list goes on. I have bags the bucket full of cold water, a little Fairy Liquid applied and a massive libation – served in the cockpit asap after I get home. You’ve got to make it on to the water taxi and off at the other end yet Miss Fitness 1978. Well............Paint Pepe’s face an alarming shade of red and stick cotton wool around the ears as pretend smoke.

Have you ever seen anyone throw a twinkling piece of basalt with such accuracy.

Bear has

But no need to run, walk fast Bear, Walk Fast.



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                     STUNNING SCENERY