Himalayan chemical weathering and carbon transfer triggered by the April 2015 Nepal Earthquake

Lead Research Organisation: University of Cambridge
Department Name: Earth Sciences


The recent Nepalese earthquakes are devastating from a humanitarian perspective, but also have a profound impact on the surface environment of the Earth. One of the major impacts of the ground movement during the Earthquakes is that it destabilises the steep hillsides in the Himalayan valleys of Nepal. This causes major landslides, some of which have been big enough to dam rivers. These landslides cause a massive pulse in fine grained rock material that is delivered into rivers, causing a pulse of sediment in the rivers. This is an active field of research. Increased sediment load can cause flooding, but our interest stems from how that fine grained sediment dissolves. This is because the dissolution of sediment has a major influence on the million year carbon cycle. Although the carbon cycle on such time-scales might seem esoteric, it is critical to understand because it is this long-term carbon cycle that has maintained the climate at the surface of the Earth within a narrow window, ultimately allowing life to develop and be sustained. Carbon and rock dissolution are linked because the main way in which rocks dissolve is via carbonic acid, which is CO2 from the atmosphere dissolved in water. When the carbonic acid dissolves rocks, it becomes neutralised as bicarbonate, a form of carbon that is present in all natural waters (check the label of a mineral water bottle for example). This bicarbonate in waters gets transferred to the oceans by rivers, where ultimately it gets converted to limestone, locking down CO2 permanently. The dominant control on rock dissolution is the supply of sediment via erosion processes, of which land sliding is one of the most important. We expect that the thousands of landslides triggered by the Nepal earthquakes will cause a massive pulse in carbon transfer via rock dissolution over the next 12 months, before the material gets washed out the system by the monsoon rainfalls. We are proposing to collect river water and sediment samples in Nepal, over the next 12 months with a series of international partners to try and better understand the perturbation that an earthquake will have caused to the carbon cycle.

Planned Impact

Nepalese hydrologists and hydropower engineers
Part of our research is to assess sediment and water fluxes. Determining the origin of the water and sediment is important to Nepalese hydrologists and hydropower engineers. Nepal's electricity generation is dominated by hydropower, though only 40% of the population have access to electricity; the bulk of the energy need being provided by wood. As Nepal tries to recover after the earthquakes and generally becomes more developed it will rely increasingly upon hydropower. Understanding the water fluxes and where they are from, such as groundwater versus surface runoff is important for planning. We will ensure that the results of our work are communicated to the Nepalese Department of Hydrology and Meteorology, the Department of Civil and Geomatics Engineering at Kathmandu University and Institute of Science and Technology at Tribhuvan University in Kathmandu.

Wider community
The project will be communicated through a Short film that will be filmed during the course of the field work. The film will be entered in the student video contest at AGU and the Communicate Your Science Video Competition video competitions to ensure maximum visibility of the science. The film will also be used to inspire future generation geoscientists and promoting the research programme for undergraduates that are choosing their degree projects. We have not budgeted for conference visits because of the urgent nature of the proposal but we fully anticipate to attend conferences and workshops such as the rapid response workshop at GFZ Potsdam, but funded by other means.

The multidisciplinary topic means that the work will be of interest for and benefit a broad group of scientific fields including 1) Chemical weathering, 2) Geomorphology and Tectonics, 3) Paleoclimate, 4) Climate modelling, 5) the carbon cycle (both short and long term), and 6) global biogeochemical cycles. Outreach to these and other end-users will be achieved in several ways including 1) making the results and data available through open-access via GEMS, NERC Data Centres, 2) high-light the project and its results on multidisciplinary webpages such as the Marie Curie ITN project iTECC, and several Cambridge College websites. We will also create our own project website and Twitter feed, with fieldwork blog such as the successful travelling geologist blog.

The general public
The Cambridge Science Centre is an educational charity that engages the public through hands-on exhibitions, workshops and talks. The results of the research will be presented in the form of short talks combined with an exhibition display at one of the Science Centre's themed events.
The Naked Scientist are a team of scientists and communicators driving a webpage and one of the world's most popular science podcasts with more than 40 million programme downloads in the last 5 years. We will produce a podcast and an associated blog post presenting the major findings of our research. The site provides a platform to communicate our results to a wide general audience with a scientific interest. We are already in contact with the Naked Scientist about the exposure of our work.


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Description This award is now complete. Critically we have collected both water and sediment samples twice during both the 2015 and 2016 monsoon seasons. Our sample collection is the most extensive ever collected from the Himalaya. The 2015 monsoon was weak but the 2016 monsoon was anomalously strong and we are still in the process of determining the magnitude of the sediment pulse attendant to the co-seismic landslides. We are in the process of analysing our samples, to quantify changes in chemical weathering. From preliminary sediment fluxes are high. We have already analysed the major element chemistry of a significant number of our samples, and there are some very interesting trends that require further work. This work is on-going despite the fact that this particular grant is concluded.
Exploitation Route Our findings will be of use to those working on chemical weathering, but are also important to hydrologists, hydro-engineers in Nepal and of significance for sediment transport. Our findings have also opened up a number of international collaborations which are ongoing. We anticipate that further funding will be obtained off the back of this urgency grant.
Sectors Construction,Education,Other
Description We have a twitter site: https://twitter.com/UCam_RiverWATCH with a small but significant number of followers.
First Year Of Impact 2015
Sector Construction,Environment,Other
Impact Types Cultural,Societal
Description Twitter research site 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Twitter feed so that others could follow our research in the field.
Year(s) Of Engagement Activity 2015
URL https://twitter.com/UCam_RiverWATCH