credit: NASA MODIS satellite image of the ash plume from the November 28, 2012, eruption, dome collapse, and pyroclastic flows. Courtesy of Rudiger Wolf, Michigan Tech.
by Emma Rodes and Adrian Hornby
Emma Rodes and Adrian Hornby, armed with Guatemala’s top mountain guide, Armando, have just completed their second five day research visit to Santiaguito’s domes, and are back for serious R&R in Quetzaltenango…but not too busy to provide an update on their field excursions.
The first trip took us to the saddle between El Brujo and El Monje where the perfect campsite presented itself, with an easy scramble to either peak. The first two days were spent exploring the hidden spaces of El Brujo, deciphering tumbledown spines and climbing remnants of the old dome. Looking for evidence of frictional slip on spine surfaces and trying to piece together the structure of the dome kept us busy, while gazing at the landscapes on this relict dome kept us awestruck.
Before we knew it the days had flown by, and for our final day we set out for El Monje in fine weather, soaked in the spines and valleys on a grand scale, then settled down for a spectacular sunset over the fumaroles of El Brujo. The following morning we packed our tents, our campsite kitchen, our crinkled clothes, sandy tents and our plastic-wrapped mountains of samples. Greatly overburdened we staggered back down El Brujo to meet the porters, promising to pack lighter the next time.
This trip was followed by three days rest in Quetzaltenango, nightly expeditions to find good meals, and many skype calls back home. Our next trip sent us to Paradise, a campsite tucked close to the beating heart of Caliente, and under the crumbling ribs of Santa Maria. The hike to Paradise is described in earlier posts, but suffice to say with a full pack it is equal in pain and grandeur.
Our first day on La Mitad, the nearest dome to Caliente, consisted a productive search of spine surfaces, and rock textures on the summit. During the first two days there were no eruptions, just passive and active (loud roaring can be heard from Caliente) degassing. However on the morning of 28th November, Caliente underwent one of its largest eruptions for 10 years, with pyroclastic flows, partial dome and flow collapses. Camped ~1km from the vent, we first learned about the eruption by phone from INSIVUMEH to our guide, Armando. We poked our heads out of our tents to see a clear view of brown and grey clouds billowing from the vent to the east, and were surprised to learn that this had been going on for an hour already. The activity continued for another half hour, plenty of time for us to observe the activity and take photos. Some of the plumes seemed to sink or fall down the flanks of Caliente, but if there were any pyroclastic flows we could not see them from our location. Intermittent flow front collapses continued for the rest of the day. Armando reported that OVSAN had seen pyroclastic flows down to 800m and a partial dome collapse on the SE flanks.
Once activity had quietened down we started to prepare breakfast. Just as it was cooked the wind changed carrying with it ash from the eruption. Within 30 seconds of the first ash landing the bright sunny morning changed to pitch black night, with visibility around 2 metres. We pitched the saucepan into the closest tent and dove in after it, devouring one of the worst breakfasts of our lives. The ash cloud persisted for two hours, thinning to cast an eerie light over the ash-covered landscape. Between 3 and 5mm ash fell around our campsite, and before striking out for the day we collected samples from the tent canopy. Up on La Mitad we worked as normal until midafternoon, when the skies over Caliente darkened again with another smaller eruption.
The following day was punctuated by a thunderstorm as we worked on La Mitad. Lightning struck metres away on Para Guatemala, the largest spine on the summit, and heavy rain forced us into cover. That evening we ate supper to the twin spectacles of Caliente’s glow and nearly constant lightning to the East.
After this unforgettable visit to Paradise we are looking forward to visits to the OVSAN observatory and the Southern lava flows over the next few days.
Really glad the PFs went to the south! So what kind of structural information are you interested in? And how are you mapping it in the field? Just curios about how that goes... and also, is the dinosaur costume part of the mapping and sampling protocol?
ReplyDeleteBuena suerte and keep us posted on the research outcomes!
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ReplyDeleteSurface Samplers