Santiaguito Post-Fieldwork Update

The fieldwork group with Santiaguito and Santa Maria in the background. From left: Yours truly, Silvio De Angelis, Andreas Rietbrock, Armando Pineda, Adrian Hornby, Anthony Lamur and Yan Lavallee.
Last Thursday I returned to the UK after an amazing three weeks of fieldwork around the Santiaguito volcano in Guatemala. For this post I will write a little bit about the experience and what had to be done during the trip. For those interested, I've also added a section at the end about the activity that we witnessed during our time there.

Quetzaltenango (also known as Xela), our base for the fieldwork. Photo taken from near the summit of Santa Maria.
After negotiating the mazy and congested streets of Guatemala City, and finally getting our equipment through customs, we arrived in the lovely little city of Quetzaltenango. Guatemala's second largest city sits in the shadow of the Santa Maria volcano, at the foot of which is the volcano we had come to study. We had a tight schedule, so there was no time for rest. We deployed 6 stations in our first three days, scattered around the volcano in easy to reach places. One of these stations was close to active lava flow so we took the opportunity to collect samples. (Over the whole trip, we collected over 200 kilos of samples to analyse and use for our experiments here in Liverpool!) At first sight the lava flow didn't appear to be moving, but frequent and large rockfalls told us that it was an unstable and moving mass of rock, and we needed to tread carefully. All in all, this was a good start, but the hardest part of our trip was to come next.

An explosion from the active Caliente vent briefly stops all activity in the campsite. 
Our task then was to deploy three stations as close as we could to the active vent at Santiaguito. This meant we had to undertake a tough 8 hour hike on a steep, slippery and dangerous trail to reach the dome complex, each carrying over 35 kilos of equipment, food and water (this doesn't include the incredible porters who carried the car batteries!) Thankfully we all arrived in one piece (plus or minus a few cuts and bruises) and managed to deploy all three stations successfully, as well as collect more samples. For one of the nights, we camped in between the exploding vent of Santiaguito (see above) and the sheer scarp formed in the cataclysmic 1902 eruption of Santa Maria (see below). It was unsettling trying to sleep with occasional and very loud roars emanating from the not-too-far-away vent, as well as almost continuous rockfalls coming down the scarp.

Sunlight hits the top of the scarp formed in the 1902 eruption of Santa Maria. 
After returning from the dome and allowing ourselves a much-needed day or two of rest, four of us (myself, Armando, Adrian and Anthony) made preparations to ascend the Santa Maria volcano to a campsite overlooking the Santiaguito complex. The route to the summit was very steep, very slippery, and very busy with tourists coming down. We arrived just as the sun was setting  and with freezing cold wind blowing in it was difficult to set up our instruments and cameras. Thankfully, after some raging at both the weather and malfunctioning laptops, we finished and settled in for a night of sleep. We were rewarded over the next 36 hours with spectacular views across the Guatemalan Highlands and down into the roaring, glowing vent. This was one of the highlights of the trip, being able to look down into the vent itself and see the glowing, roaring lava. We were also lucky enough to be able to see Fuego in the distance and see a couple of small explosions rising from it.

An explosion plume rises from the vent, taken from the viewpoint near our campsite on Santa Maria. The active 2014 lava flow can be seen on the left hand side of the vent.
That was the last act of our fieldwork and after the small matter of trying to ship nearly quarter of a tonne of rock samples it was time for us to say goodbye to Guatemala. Santiaguito is an incredible and exciting place, but is also one of the physically demanding places to work in. We are grateful to the local landowners who let us bury our instruments on their land, and the superhuman porters who carried our heaviest items into the field. We are also grateful to Gustavo Chigna of INSIVUMEH for helping us and letting us use some of the existing station locations. Last, but not least, we are really grateful to our guide Armando Pineda who went above and beyond to help us in almost everything we did. A group of us will be returning in March to retrieve the instruments and data and I really cannot wait to go back.

Adrian Hornby, Anthony Lamur and yours truly pose in front of the glowing vent of Santiaguito. 
Activity update: As you might have guessed from the above text, Santiaguito is very active at the moment. We witnessed many explosions, occurring at irregular 30-90 minute intervals. The explosions had variable quantities of ash and gas, with the latter dominating most explosions. Plumes from the biggest explosions were rising up to and over 1000 m above the vent (we witnessed plumes rising higher than our campsite on Santa Maria at ~3600 m altitude). One particular explosion was accompanied by a small pyroclastic flow but unfortunately visibility was limited by clouds so we could not see it. Inside the vent, we could see incandescent blocky lava which was supplying the lava flow. The flow itself is moving at a very low rate with frequent but small clouds of ash coming from rockfalls along it's length and particularly the flow front. We also saw damage caused by lahars to a coffee plantation below the lava flow; the lahars are being redirected into the plantation by the lava flow filling up the old pathway.