Project: Volcan Baru

A 5-day visit with volcanologists...

The adventure shed light on the far corners of the field while also establishing a scope for the project. While new questions cropped up during the trip, the theme never changed:
What is going on with these debris deposits?!

What we were looking for:
Multi-colored, buried blocks that explain the insides of debris avalanches. Within massive quarries, road and stream-cuts, and construction sites, the presence OR absence of these features provides information about composition and energy.

Textures, when volcanoes fall down, particular things happen to the rocks: fracturing, shattering, shearing, disaggregation... that is to say: busted up. Something we're seeing at the distal end of the deposit is jigsaw fracturing. Not every block is like this, but by now I've seen enough of these to link it with the mixed-up phase of the avalanche. This photo is an example, rock hammer for scale.

Topographic clues, despite the estimated age of the events, the topography still tells us something about the past - and adds a few more questions to the whole picture, but it's no good to ignore the hints given by aerial photos, digital elevation models, topo maps, and panoramic views. There is a 20-square kilometer area that is dissected by erosion and abruptly becomes high, rolling plateau - why?

Carbon samples, wood or charcoal or bulk soil samples that can date or at least constrain the timing of events. As far as I'm concerned, finding 7 samples within a 5-day visit is as good as it gets for a debris avalanche.

Contacts, we were lucky to gain access to the largest construction site I've seen in Panama. A new dam is going in on the Rio Chiriqui Viejo - I learned that there could be 10 more built sometime in the future, interesting... Here, the excavation is cutting so deeply that we saw both debris avalanche material and the underlying bedrock exposed within the same view. Construction workers looked like specks and whether they knew it or not, they were pointing out the unit base for us - thanks guys!

Places like this will be worthwhile to revisit. This kind of construction requires incredible excavation, in the river valley as well as further away where quarries appear to provide gravel for all of the concrete needed to stabilize the slopes.

The 5 days were a success - we have new information and ideas about Volcan Baru's debris avalanche deposits. Also, there was time to talk-story with friends and enjoy the best sunset spot I've ever seen in Panama.

Project: Volcan Baru

This is just a quick update - quicker than normal.

The research I plan on doing based on Volcan Baru is progressing, just as it has been since I arrived, but NOW it's time to actually blog about it.

After a year spent in-country and focusing on Peace Corps activities, the hardcore geology work is now ready to take center stage. That is to say, when I'm not juggling aqueduct and latrine construction, I am hiking (or bicycling as it may be) out to my field area to map a volcanic deposit.

The fieldwork has already begun and I'm not joking about taking a bike, my research area is huge and there is a lot of ground to cover. Where am I working? Here:

(The USGS map shows 3 shaded areas: blue is Volcan Baru's edifice, brown is the lahar flow field, and in green is where I am working: the debris avalanche deposit, DAD. The original paper where you can see this map and the full explanation is here: http://pubs.usgs.gov/of/2007/1401/)

How do you map a VDAD? The primary features I'm focusing on are the hummocks, already deeply buried by thousands of years of lahar flows, but with a little help of aerial photos and lots of time spent "hoofing it" - I'll be able to map out the extent of the region and hopefully gather enough information to explain how such a large-scale event occurred and when.

More fieldwork should have happened in November, but renewed construction in-site and VERY bad weather changed my plans. During the week of the 16th a major storm system approached Panama's northern coast. A huge cell of rain (is that correct to say? maybe it's better to say "cells") moved in from the Caribbean and sat over the shoreline dumping rain and rising winds. Rivers were flooding, small streams graduated to rushing highways of mud, landslides covered major roads, bridges were damaged, houses were washed away, fincas were drowned, and unfortunately, some rescue efforts failed.
(Photo by Angel Rodriguez; road to Cerro Punta; Rio Chiriqui Viejo)

(Photo by SINAPROC staff; aerial view of flooding in Bocas del Toro, Nov. 16-30, 2008; http://www.sinaproc.gob.pa)

Formal report here: United Nations report

PC Volunteers were evacuated where possible, in some cases it was better to ride out the storm than cross the bay of Bocas del Toro, but it's going to be difficult for many of them to return to their sites.

Good luck you guys!

Volcano Fieldwork Part 2

February 17-20th: What is this rocky prairie? This photo was taken just seconds before the clouds moved in completely to take away the view of the summit dome. My volcanological companions and I visited Volcan Baru´s amphitheater during an uncharacteristically rainy week. After exploring the area of La Yeguada with PCVs Karinne and Noah, we took the Interamericana, headed west, then drove due north to the volcano. This was a good time to visit the largest known debris avalanche in Central America. The photo above is a view into the amphitheater of Volcan Baru. We are standing on a lahar surface and looking roughly East up into the dome complex. Too bad about the weather, the summit antennas are already hidden by the incoming rain.

Since we had the benefit of several great geological minds, we took time to look at a phenomenon very different than lava flows. Debris avalanches are dramatic, but very rare events at volcanoes. By rare, I mean that they don´t happen every day but many volcanoes around the world have collapse features like what you can see at Baru. Some preliminary studies describe this particular deposit as the largest in Central America. What does that mean? At this point it just means that a whole lot of mountain fell down many thousands of years ago.

Want to know more about hummocks? Go here: USGS VHP

Events like this are very interesting for a number of reasons but I´m interested in them because they scoop out a volcano and create new terrain. After walking around Mount St. Helens for a while in 2004, I developed a particular interest in the features called hummocks. They represent coherent blocks that tumbled, slid, or floated along with the rest of the debris that made up the flanks of a volcano. Here´s one outcrop of a hummock but it represents a blocky phase and lacks the multicolored characteristic typical of most hummocks:

(Bill, Guillermo, and Karinne for scale)

In the fan of deposits from Baru, you can find these hummocks and start to get an idea of how the collapse took place- this could be good thesis material.

Thanks for taking the time to visit and brainstorm project plans, everybody - this was a valuable series of fieldtrips!