The Awakening of Momotombo Volcano, Nicaragua

Contribution by Gino González Ilama, University of Costa Rica

Introduction

Central America is home to more than 50 active volcanoes, with many large eruptions over the course of history. The volcanism in the region is widespread, including effusive, explosive and phreatic eruptions occurring today. The main source of volcanic eruptions in Central America is the subduction of the Cocos and Nazca plates beneath the Caribbean plate.

Momotombo volcano is located 40 km to the NW of Managua, the capital of Nicaragua. In 1609 this volcano was responsible for an important migration of civilians to Leon City, due to several events which affected the old town including earthquakes, ash fall and even lava flow.

After 110 years of silence, on December 1st, 2015, Momotombo volcano began to erupt again with large scale lava flow on the NE flank. Some of this lava flow was visible from Managua (about 40 km away on the other side of the Managua Lake).

With this in mind, we visited the volcano 12 days after the first event. Our purpose was to measure thermal anomalies with the FLIR camera (Forward Looking Infrared Camera), take samples of the lava flow and describe the event.

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Figure 1. Location and tectonic context of Momotombo volcano. The area marked with MO denotes the location of the sampling site along the new lava flow.

Results

The lava flow descended on the NE flank, partially over the lava flow of 1905. This flow traveled 2 km from the top, with a volume of lava flow around 6×106 m3. This flow was delimited by consolidated levées, denoted by the FLIR camera.

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Figure 2. Eruptions and lava flows of Momotombo volcano. a) effusive eruption, December 3rd, 2015. Photo credit AP; b) Lava flows of 1905 and 2015; c) explosive eruption of February 21st, 2016. Photo credit Álvaro Sánchez.

Macroscopically, the rocks are porphyritic basalt-andesite, with olivine (5%) and plagioclase (35%), and 15% porous.

The type of the lava flow is aa and has two parts: upper part was rough and sharp, and the lower part was continues hot. Also, many features related with the movement of the flow and change in the velocity and topography can be observed at that time on the site.

With the Flir Camera we measured around 700 °C, principally in the pipes, with some minerals in the boundaries.

After the lava flow…

Now (February/March 2016), the Momotombo volcano has changed its behavior presenting episodes of explosive activity, and the big deal will be: Why has it changed from effusive to explosive? It is difficult to explain, but maybe this explosive activity is due to the formation of a plug in the conduit or a summit dome and this could have increase the gas pressure in the conduit (F. Lucchi, written communication).

Along with this change in the activity, hazards have also changed. This is because explosive activity is generating pyroclastic density currents, driving more than 2 km at times, and ash plumes of more than 2 km height.

In this perspective, Momotombo volcano is a good example of how volcanoes wake up, and how they can change activity and hazard with each eruption.

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Figure 3. View of Momotombo volcano and pipes in the lava flow. a) View of Momotombo volcano; b) thermal image of Momotombo volcano, the hottest color is the levées; c) pipe in the lava flow; d) thermal image of the pipe in other hot points.

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Figure 4. Lava flow of Momotombo volcano and different features: a) collecting samples in the MO point indicated in Fig.1; b) macroscopic texture of the rock sample; c) and d) different structures related with the lava flow movement.

A birdseye view of the sampling site

The area within the Furnas Volcano (São Miguel, Azores) influenced by secondary geothermal manifestations is not particularly big. You can walk all of it in about 30 minutes. Despite this the diversity of geothermal activity is impressive. The entire area is situated few tens of meters from the caldera lake, and effluents from the hydrothermal area flow directly into the lake waters. The hydrothermally altered ground in the main area is about the size of a football field, and contain solfataras, boiling pools, numerous fumaroles, boiling mud pools and several degassing and hot spots in the entire zone.

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Satellite view (Google Maps) of the Furnas caldera lake in São Miguel, Azores

There are also numerous diffuse degassing areas on the shores of the lake, and underwater degassing and hot fluids vents are evident venturing few feet into the water.

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View of the geothermally influenced area of Furnas Volcano from the nearby parking lot. Credit DCO/Katie Pratt

For the sampling we selected an area representative of the diverse environments, yet safe enough for numerous people to work at the same time. Geothermally altered grounds, especially if still active, can be extremely unstable, and often be made of a thin crust covering large pools of near-boiling waters. For everyone safety we decided to limit our sampling to and area considered relatively stable.

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A Birdseye view of the sampling location obtained by photomosaic. Credit Donato Giovannelli

As you can see in the picture above, the area we selected (delimited by the red line) contains different features, including soils not influenced by the geothermal activity (F). The large red square marked with *, represent the area were DCOECS15 participants Matteo Masotta, with the help of local expert and DCOECS15 participant Vittorio Zanon, performed the stratigraphy already appeared on this blog.

The sampling site, Furnas, Azores
The sampling site looking back towards the lake from the fumarole. Credit DCO/Katie Pratt

The sampled locations within this plot were: A the sediments of a hot pool; B the fluids and sediments of a bubbling fumarole; while D, C and E represented different point along the outflow channel connecting the fumarole and hot pool with the lake, located outside the field of view of the previous picture on the right side; F was a control site not directly influenced by the geothermal activity.

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Diversity of the sampling environments. Credit Donato Giovannelli

For each site we performed a large number of measurements and collected numerous samples for further laboratory analyses. Among others, this included CO2 fluxes for the entire area, gas composition measurement and isotopes, mineralogical analyses, major and minor elements, geochemistry, quality and quantity of the organic matter and a suite of microbiological analyses. Sometime in the near future my colleagues will start to blog about the results that we are slowly compiling in a large database.

Alysia Cox takes samples. Credit: DCO/Katie Pratt
Alysia Cox takes samples. Credit: DCO/Katie Pratt

Why Open Science?

A lot has been said about Open Source, Open Data and Open Science (just google it to see the sheer amount of pages coming up), and data sharing and open access publishing mandate is something all major funding sources are implementing (see the OSTP Open Data Mandate from the US government. Similar mandate are now present also in Europe and other nations).

In some disciplines this is no news. The molecular biology community has been ahead of the open science and open data game for years, as the deposition into public and open database of all sequences is a prerequisite for publishing (and this extends to organisms, plasmids, and other biological constructs). Open Source software development (especially science oriented in this context) is another good example.

Besides the funding agency pressure, and the hot topic wave following the open movement you should opt for a open model for many other reasons. Recently, I watched a wonderful talk on line by Matthew Todd, the founder of the Open Source Malaria project. If you never heard of this project watch the video below, head to the http://opensourcemalaria.org website and check one of their experiments. Perhaps you could contribute to the fight against malaria (and you can do it even if you are not a scientist, as explained here.

As Matthew explains toward the end of the video, Open Science is transparent, is immortal and it’s fast. If you think about this for some time, it can really change your perspective on the issue. And while the Open Science model still has its loose ends (see here and here for a quick hints to some of the problems), I believe Open Science is the way of the future.

At the last Deep Carbon Observatory Early Career Scientist Workshop we thought it was time to do the same, and share with everyone our science, and the making of it. During the workshop we designed and performed a multidisciplinary co-located sampling effort, aimed at characterizing multiple aspect of carbon science at a single geographic location (Furnas Volcano, São Miguel, Azores, Portugal). We decided that beside the final publication, also the experiments, the analyses and the raw data should be part of the public domain, to help scientist and educators to build on our work, as fast and efficiently as possible.

Keep following us to see the hows and whys of our collective open science project!