Geology for Global Development

Rosalie Tostevin

Rosalie was the Himalayas Programme Officer for Geology for Global Development and writer for the GfGD blog. She is a geochemist and a postdoc at the University of Oxford.

Mapping the Kaikoura earthquake, New Zealand

Jscreen-shot-2016-11-30-at-17-08-09ack Williams is a PhD Student at the University of Otago, New Zealand, where he is studying the Alpine Fault. Jack was part of a team of experts that went into the field immediately following the Kaikoura earthquake to map the surface ruptures. Here he explains what they were up to and shares some photos of the damage.

The Mw 7.8 Kaikoura Earthquake was an incredibly complex event involving several faults; and to unravel its movement we need accurate maps of the surface ruptures that slipped during the earthquake. A team from the University of Otago comprising myself, Mark Stirling, Kat Sauer and David Barrell (GNS Science) spent the past week mapping the Hundalee Fault, where helicopter reconnaissance flights had tipped us off about surface ruptures. This fault lies close to the epicentre of the Kaikoura event, but to the south of the Kekerengu Fault, across which ~10 m displacement has been widely reported.

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In this photo of State Highway 1 (SH1), tensional cracks formed around the scarp from gravitational deformation induced by ground shaking in the earthquake

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‘Crevasses’ in road

The observations that needed to be made included: measuring displacement across the fault, constraining the length of surface rupture along-strike of the Hundalee Fault, and whether we could identify previous events along the sections that ruptured on the 14th of November. ‘Surface rupture’ refers to places where the earthquake rupture broke through to the surface and caused offset across recognisable markers such as roads and fence posts.

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Here the offset was a combination of uplift with the far side of the road uplifted 1 m, and dextral, meaning that the far side of the road moved horizontally to the right (as can be seen in the centre road markings). This type of movement with two components, is referred to as ‘oblique-slip’ and has been recognised across the Kaikoura Earthquake

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Surface rupture crossing the Te Moto Moto Stream. These rapids likely weren’t here a few weeks ago!

Mark has been busy accurately mapping the fault trace using a Real Time Kinematic (RTK) GPS, whilst Kat and myself have been getting to grips with the department Unmanned Aerial Vehicle (UAV, i.e. a drone) to capture birds-eye views and videos of the surface rupture. By taking overlapping photos, we hope to generate 3D photogrammetry models of the ruptures. We have also seen bedrock exposures of the Hundalee Fault across a creek that was uplifted ~1 m during the earthquake, with exceptional examples of gouges and cataclasites, including some cataclasite strands that did not appear to slip in this event.

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A drone’s eye view of the surface rupture

These results will feed into the larger scale picture that is beginning to emerge from this earthquake, and will no doubt keep us busy for many years ahead. For example, why in some locations do we observe sinistral offset on a fault that predominantly has dextral offset, and, what is controlling the segmentation and jumps in the ruptures we have identified? From a personal point of view, it has been an eye opening experience into a side of earthquake geology I have never dealt with before, and also the importance of the science community engaging with those who have been affected with this event.

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Landslide covers the rail tracks that run along the east coast of the South Island.

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A bold warning from a local resident affected by the earthquake.

Guest Blog: Exploring Land Use in Guatemala

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Jane Robb is GfGD’s University Groups Training Programme Officer, and a new PhD student at the Natural Resources Institute, University of Greenwich. Jane has just returned from Guatemala, where she was meeting with community groups and exploring land use issues. Here she shares some of the highlights of her trip with us.

In 2014 I started my PhD in Natural Resources at the Natural Resources Institute at the University of Greenwich. My project, in collaboration with the University of Valle, Guatemala, is currently exploring the institutional context within which land use changes and deforestation occur, and how this can inform the development of a Reduction of Emissions from Deforestation and Forest Degradation in Developing Countries (REDD+) project in the Sierra de las Minas Biosphere Reserve. I say currently, as the location has changed a little since I started the PhD (originally Sierra Leone, then Peru, then Madagascar, then Guatemala), and so has the focus of the project (first drivers of change in landscape carbon stocks, then understanding decision processes, then institutional analysis). By the time this post is published, I will probably be doing something else.

Coincidentally, GfGD are running a fundraising project throughout the year focusing on Guatemala, so I thought I would take this opportunity to provide readers with a photographic tour of my first 7-week field trip of my PhD, to Guatemala.

Out of a car, on my way to the first meeting in the city, I get a glimpse of Guatemalan life.

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The first two weeks of my trip involved tailing my supervisor, who was finishing up a project funded by The Darwin Initiative on agroforestry for sustaining biodiversity of shaded coffee and cocoa plantations. This was an ideal start, as I was introduced to many key people for the rest of my stay and it gave me a crash course on Guatemala. This photo is the finale conference for the project, held at ANACAFE (the national coffee association for coffee cooperatives) offices in the city with several delegates from across Guatemala and the UK drinking ANACAFE coffee to kick off the conference.

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After the conference presenting the results of the project, I accompanied Jeremy and colleagues to visit some of the coffee plantations they had been working with, to see their progress in person. This was my first glimpse of the Sierra de las Minas Biosphere Reserve, at dusk in a small hotel just off the Polochic valley.

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The next day we made the journey up towards the centre of the Biosphere Reserve. Once we reached the community, we had a perfect view onto the nuclear zone. However, it was clear that deforestation had been encroaching into the nuclear zone, where all use of the forest (other than for scientific research and ecotourism) is banned.

SAM_0782After consultation with the community representatives about the state of their coffee plantations, we stopped for a photo with wooden cardamom driers as a backdrop, then joined them for some lunch.

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On our way back down the mountain, up close, the extent of deforesting and land degradation was clear.

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In the Polochic valley at the base of the Sierra las Minas, we drove through monoculture plantations of sugar cane and oil palm, one of the newer threats to biodiversity and land degradation in Guatemala.

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On our way back to the city, we encountered some incredible views of the countryside that even deforestation couldn’t mar.

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After returning to the city briefly, we then made our way out towards another community, this time south west of the city near the famous town of Quetzaltenango. Here we attended the offices of a coffee cooperative, where members of the Darwin project team discussed their results with the plantation owners.

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In a third community nearby, we were taken on a hiking tour of their plantations.

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Later, members of the coffee cooperative were presented with biodiversity maps and information books on agroforestry.

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With time for a little relaxation, we visited some Mayan ruins. (A must do in Guatemala!)

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And of course viewed some of Guatemala’s incredible geologic forces at work.

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By the time my supervisor left at the end of my second week, it was Easter and time for the uniquely Guatemalan week long celebration of Semana Santa. Here you can see carpets of vegetables and seeds laid out on the streets of the city (alfombras), over which the Catholic processions would progress later that afternoon.

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I was lucky to have some time to explore the stunning cultural centre of the city during this week of revelry.

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Guatemala takes the holy week of Semana Santa very seriously, so I thought I would follow tradition and take the holiday seriously too. I headed off to the party capital of Guatemala, Lake Atitlan, where I also took a week of Spanish lessons.

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And kayaked.

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With my third week over, it was back to work. This mainly consisted of attending meetings and working from the Centre for Study of the Environment and Biodiversity (CEAB) at the University of Valle. We did manage to take a short visit to some forestry plantations, to estimate the carbon content of different types of plantations in order to develop a comprehensive view of the carbon emissions and sinks in Guatemala for the national United Nations Framework Convention of Climate Change (UNFCCC) and Forest Carbon Partnership Facility (FCPF) supported REDD+ programme. We might have also found time to stay a night at Lake Atitlan that trip, as it was such a long drive back home…

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