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Diogo Lourenço & Antoine Rozel

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How the EGU works: Experiences as GD Division President

How the EGU works: Experiences as GD Division President

In a new regular feature, Paul Tackley,  president of the EGU geodynamics division, writes about his role as a president, and gives us an insider’s view on how EGU works and is preparing for the future. 

Paul Tackley. Professor at ETH Zürich and EGU geodynamics division president. Pictured here giving an important scientific talk, or maybe at karaoke. Your pick.

Stepping into the role of GD Division President has given me a big learning experience about how the European Geosciences Union is run and about how members are represented and can participate. Here I convey some impressions, give a quick overview of how EGU functions and the role of division presidents, and mention a few other activities you may not be aware of.

Firstly, I was impressed just how much a bottom-up organisation the EGU is – how it is run by members for the benefit of members. EGU employs only 7 full-time staff – very few compared to the 140+ employed by the American Geophysical Union! Thus, most of the organisation is run my volunteers, including the big jobs of President, Vice-President, Treasurer and General Secretary, and also the presidents of the 22 scientific divisions and members of eight committees. Of course, the fact that so few staff are needed is helped by the fact that Copernicus (the company) deals with publishing all the journals and organising the General Assembly (GA), and Copernicus has 54 employees.

Secondly, I now appreciate that EGU does a lot more beyond organising the General Assembly and publishing 18 open access journals. In particular, EGU is active in the areas of Education and Outreach, and supports various Topical Events, with each area coordinated by a committee. Additionally, a Diversity and Equality working group was recently set up. I encourage you to read more about these various activities on EGU’s web site.

What must a division president do?  The main tasks are to organise the division’s scientific programme at the General Assembly, and to attend three EGU Council + Programme Committee meetings per year: short ones at the General Assembly, and longer (2-3 days) ones in October near Munich, and in January somewhere warm (such as Nice or Cascais). Practically, this involves sitting in a darkened room for 2-3 days with a lot of other people (there are many other members in addition to the division presidents, including early career scientists) listening to information of variable interest level and discussing and making decisions (voting) when necessary. The EGU Council discusses the full range of EGU activities, so meetings consist of a series of reports: from the president, the treasurer, the various committees, the ECS representative, etc., often with much time spent discussing and voting on new points and developments that arise. Programme Committee meetings are focussed on the General Assembly, both discussing general issues and accomplishing the specific tasks of finalising the list of sessions (October meeting) and the session schedule (January meeting). Throughout all these meetings, I have found the council members to be very collegial and constructive in trying to do what is best for improving EGU activities and making optimal arrangements for the General Assembly (although of course, opinions about what is best can vary). Additionally, Copernicus is continually improving their online tools to make scheduling easier.

The President Alberto Montanari, Programme Committee Chair Susanne Buiter and Copernicus Managing Director Martin Rasmussen, celebrating the EGU General Assembly.

I am happy that there are several other people actively taking care of various tasks in the GD Division. Division officers stimulate sessions in their respective areas of the GA programme and judge the Outstanding Early Career Scientist Award nominations, while judging of the OSPP (Outstanding Student Poster and Pico) awards is organised by an Early Career Scientist (now Maelis Arnould). Our Early Career Scientists are incredibly active, maintaining this blog and the Facebook page, and organising social events at the GA. Finally, the Medal committee decides the winner of the Augustus Love Medal.

Changes are ongoing at EGU! In a multi-year process the finances are being moved from France to Germany, a complicated process as described by our Treasurer at the GA Plenary session. Moving the EGU office (where the 7 people work) from a confined space on the campus of Ludwig Maximilian University of Munich to a much larger modern office premises is happening around now and will allow some expansion of the staff and a suitable space to greet visitors. In the longer term, it may be necessary to move the location of the General Assembly from Vienna due to the ever-increasing number of attendees!

To conclude, EGU is our organisation and we can contribute to the running of it and the decision-making process, so I encourage you to get involved and to make your views about possible future improvements or other issues known to your representative (i.e. me, or our Early Career Scientist representative Nicholas Schliffke). And if anyone wants to take over as the next GD Division President, (self-)nominations can be submitted starting in September with the vote coming in November!

Programme Committee of EGU, which includes its chair, all the division presidents, the executive board, key people from Copernicus and Programme Committee Officers including the ECS representative and OSPP coordinator.

On the resolution of seismic tomography models and the connection to geodynamic modelling (Is blue/red the new cold/hot?) (How many pixels in an Earth??)

What do the blobs mean?

Seismologists work hard to provide the best snapshots of the Earth’s mantle. Yet tomographic models based on different approaches or using different data sets sometimes obtain quite different details. It is hard to know for a non specialist if small scale anomalies can be trusted and why. This week Maria Koroni and Daniel Bowden, both postdocs in the Seismology and Wave Physics group in ETH Zürich, tell us how these beautiful images of the Earth are obtained in practice.

Daniel Bowden and Maria Koroni enjoying coffee in Zürich

Seismology is a science that aims at providing tomographic images of the Earth’s interior, similar to X-ray images of the human body. These images can be used as snapshots of the current state of flow patterns inside the mantle. The main way we communicate, from tomographer to geodynamicist, is through publication of some tomographic image. We seismologists, however, make countless choices, approximations and assumptions, which are limited by poor data coverage, and ultimately never fit our data perfectly. These things are often overlooked, or taken for granted and poorly communicated. Inevitably, this undermines the rigour and usefulness of subsequent interpretations in terms of heat or material properties. This post will give an overview of what can worry a seismologist/tomographer. Our goal is not to teach seismic tomography, but to plant a seed that will make geodynamicists push seismologists for better accuracy, robustness, and communicated uncertainty!

A typical day in a seismologist’s life starts with downloading some data for a specific application. Then we cry while looking at waveforms that make no sense (compared to the clean and physically meaningful synthetics calculated the day before). After a sip, or two, or two thousand sips of freshly brewed coffee, and some pre-processing steps to clean up the mess that is real data, the seismologist sets up a measurement of the misfit between synthetics and observed waveforms. Do we try to simulate the entire seismogram, just its travel time, its amplitude? The choice we make in defining this misfit can non-linearly affect our outcome, and there’s no clear way to quantify that uncertainty.

After obtaining the misfit measurements, the seismologist starts thinking about best inversion practices in order to derive some model parameters. There are two more factors to consider now: how to mathematically find a solution that fits our data, and the choice of how to choose a subjectively unique solution from the many solutions of the problem… The number of (quasi-)arbitrary choices can increase dramatically in the course of the poor seismologist’s day!

The goal is to image seismic anomalies; to present a velocity model that is somehow different from the assumed background. After that, the seismologist can go home, relax and write a paper about what the model shows in geological terms. Or… More questions arise and doubts come flooding in. Are the choices I made sensible? Should I make a calculation of the errors associated with my model? Thermodynamics gives us the basic equations to translate seismic to thermal anomalies in the Earth but how can we improve the estimated velocity model for a more realistic interpretation?

What do the blobs mean?

Figure 1: A tomographic velocity model, offshore southern California. What do the blobs mean? This figure is modified from the full paper at https://doi.org/10.1002/2016JB012919

Figure 1 is one such example of a velocity model, constructed through seismic tomography (specifically from ambient-noise surface waves). The paper reviews the tectonic history of the crust and upper mantle in this offshore region. We are proud of this model, and sincerely hope it can be of use to those studying tectonics or dynamics. We are also painfully aware of the assumptions that we had to make, however. This picture could look drastically different if we had used a different amount of regularization (smoothing), had made different prior assumptions about where layers may be, had been more or less restrictive in cleaning our raw data observations, or made any number of other changes. We were careful in all these regards, and ran test after test over the course of several months to ensure the process was up to high standards, but for the most part… you just have to take our word for it.

There’s a number of features we interpret here: thinning of the crust, upwelling asthenosphere, the formation of volcanic seamounts, etc. But it wouldn’t shock me if some other study came out in the coming years that told an entirely different story; indeed that’s part of our process as scientists to continue to challenge and test hypotheses. But what if this model is used as an input to something else as-of-yet unconstrained? In this model, could the Lithosphere-Asthenosphere Boundary (LAB) shown here be 10 km higher or deeper, and why does it disappear at 200km along the profile? Couldn’t that impact geodynamicists’ work dramatically? Our field is a collaborative effort, but if we as seismologists can’t properly quantify the uncertainties in our pretty, colourful models, what kind of effect might we be having on the field of geodynamics?

Another example comes from global scale models. Taking a look at figures 6 and 7 in Meier et al. 2009, ”Global variations of temperature and water content in the mantle transition zone from higher mode surface waves” (DOI:10.1016/j.epsl.2009.03.004), you can observe global discontinuity models and you are invited to notice their differences. Some major features keep appearing in all of them, which is encouraging since it shows that we may be indeed looking at some real properties of the mantle. However, even similar methodologies have not often converged to same tomographic images. The sources of discrepancies are the usual plagues in seismic tomography, some of them mentioned on top.

410 km discontinuity

Figure 2: Global models of the 410 km discontinuity derived after 5 iterations using traveltime data. We verified that the method retrieves target models almost perfectly. Data can be well modelled in terms of discontinuity structure; but how easily can they be interpreted in terms of thermal and/or compositional variations?

In an effort to improve imaging of mantle discontinuities, especially those at 410 and 660 km depths which are highly relevant to geodynamics (I’ve been told…), we have put some effort into building up a different approach. Usually, traveltime tomography and one-step interpretation of body wave traveltimes have been the default for producing images of mantle transition zone. We proposed an iterative optimisation of a pre-existing model, that includes flat discontinuities, using traveltimes in a full-waveform inversion scheme (see figure 2). The goal was to see whether we can get the topography of the discontinuities out using the new approach. This method seems to perform very well and it gives the potential for higher resolution imaging. Are my models capable of resolving mineralogical transitions and thermal variations along the depths of 410 and 660 km?

The most desired outcome would be not only a model that represents Earth parameters realistically but also one that provides error bars, which essentially quantify uncertainties. Providing error bars, however, requires extra computational work, and as every pixel-obsessed seismologist, we would be curious to know the extent to which uncertainties are useful to a numerical modeller! Our main question, then, remains: how can we build an interdisciplinary approach that can justify large amounts of burnt computational power?

As (computational) seismologists we pose questions for our regional or global models: Are velocity anomalies good enough, intuitively coloured as blue and red blobs and representative of heat and mass transfer in the Earth, or is it essential that we determine their shapes and sizes with greater detail? Determining a range of values for the derived seismic parameters (instead of a single estimation) could allow geodynamicists to take into account different scenarios of complex thermal and compositional patterns. We hope that this short article gave some insight into the questions a seismologist faces each time they derive a tomographic model. The resolution of seismic models is always a point of vigorous discussions but it could also be a great platform for interaction between seismologists and geodynamicists, so let’s do it!

For an overview of tomographic methodologies the reader is referred to Q. Liu & Y. J. Gu, Seismic imaging: From classical to adjoint tomography, 2012, Tectonophysics. https://doi.org/10.1016/j.tecto.2012.07.006

How to make a subduction zone on Earth

How to make a subduction zone on Earth

Subduction zones are ubiquitous features on Earth, and an integral part of plate tectonics. They are known to have a very important role in modulating climate on Earth, and are believed to have played an essential part in making the Earth’s surface habitable, a role that extends to present-day. This week, Antoniette Greta Grima writes about the ongoing debate on how subduction zones form and persist for millions of years, consuming oceanic lithosphere and transporting water and other volatiles to the Earth’s mantle.

Antoniette Greta Grima. PhD Student at Dept. of Earth Sciences, University College London, UK.

Before we can start thinking about how subduction zones form, we need to be clear on what we mean by the term subduction zone. In the most generic sense, this term has been described by White et al. (1970) as “an abruptly descending or formerly descended elongate body of lithosphere, together with an existing envelope of plate deformation”. In simple words this defines subduction zones as places where pieces of the Earth’s lithosphere bend downwards into the Earth’s interior. This definition however, does not take into account the spatio-temporal aspect of subduction zone formation. It also, does not differentiate between temporary, episodic lithosphere ‘peeling’ or ‘drips’, thought to precede the modern-day ocean plate-tectonic regime (see van Hunen and Moyen, 2012; Crameri et al., 2018; Foley, 2018, and references therein) and the rigid self-sustaining subduction, which we see on the present-day Earth (Gurnis et al., 2004).

A self-sustaining subduction zone is one where the total buried, rigid slab length extends deep into the upper mantle and is accompanied at the surface by back-arc spreading (Gurnis et al., 2004). The latter is an important surface observable indicating that the slab has overcome the resistive forces impeding its subduction and is falling quasi-vertically through the mantle. Gurnis et al. (2004) go on to say that if one or the other of these defining criteria is missing then subduction is forced rather than self-sustaining. Forced or induced subduction (Stern, 2004; Leng and Gurnis, 2011; Stern and Gerya, 2017; Baes et al., 2018) is described by Gurnis et al. (2004) as a juvenile, early stage system, that cannot be described as a fully fledged subduction zone. These forced subduction zones are characterised by incipient margins, short trench-arc distance, narrow trenches and a volcanically inactive island arc and/or trench. Furthermore, although these juvenile systems might be seismically active they will lack a well defined Benioff Zone. Examples of forced subduction include the Puysegur-Fiordland subduction along the Macquarie Ridge Complex, the Mussau Trench on the eastern boundary of the Caroline plate and the Yap Trench south of the Marianas, amongst others. On the other hand, Cenozoic (<66 Ma) subductions, shown in figure 2, are by this definition self-sustaining and mature subduction zones. These subduction zones including the Izu-Bonin-Mariana, Tonga-Kermadec and Aleutians subduction zones, are characterised by their extensive and well defined trenches (see figure 2) (Gurnis et al., 2004). However, despite their common categorization subduction zones can originate through various mechanisms and from very different tectonic settings.

Figure 1: Map the Earth’s subduction zones and tectonic plates from W.K and E.H. (2003). See how subduction zones dominate the figure.

1. How are subduction zones formed?

We know from the geological record that the formation of subduction zones is an ongoing process, with nearly half of the present day active subduction zones initiating during the Cenozoic (<66 Ma) (see Gurnis et al., 2004; Dymkova and Gerya, 2013; Crameri et al., 2018, and references therein). However, it is less clear how subduction zones originate, nucleate and propagate to pristine oceanic basins.

 

Figure 2: The oldest, still active subduction zones on Earth can be dated back to 66 million years ago. These are self- sustaining mature subduction zones with well defined trenches and trench lengths (modified from Gurnis et al., 2004).

Crameri et al. (2018, and references therein) list a number of mechanisms, some which are shown in figure 3, that may work together to weaken and break the lithosphere including:

  • Meteorite impact
  • Sediment loading
  • Major episode of delamination
  • Small scale convection in the sub-lithospheric mantle
  • Interaction of thermo-chemical plume with the overlying lithosphere
  • Plate bending via surface topographic variations
  • Addition of water or melt to the lithosphere
  • Pre-existing transform fault or oceanic plateau
  • Shear heating
  • Grain size reduction

Some of these mechanisms, particularly those listed at the beginning of the list are more appropriate to early Earth conditions while others, such as inherited weaknesses or fracture zones, transform faults and extinct spreading ridges are considered to be prime tectonic settings for subduction zone formation in the Cenozoic (<66 Ma) (Gurnis et al., 2004). As the oceanic lithosphere grows denser with age, it develops heterogeneity which facilitates its sinking into the mantle to form new subduction zones. However, it is important to keep in mind that without inherited, pre-existing weaknesses, it is extremely difficult to form subduction zones at passive margins. This is because as the oceanic lithosphere cools and becomes denser, it also becomes stronger and therefore harder to bend into the mantle that underlies it (Gurnis et al., 2004; Duarte et al., 2016). Gurnis et al. (2004) note that the formation of new subduction zones alters the force balance on the plate and suggest that the strength of the lithosphere during bending is potentially the largest resisting component in the development of new subduction zones. Once that resistance to bending is overcome, either through the negative buoyancy of the subducting plate and/or through the tectonic forces acting on it, a shear zone extending through the plate develops (Gurnis et al., 2004; Leng and Gurnis, 2011). This eventually leads to plate failure and subduction zone formation.

Figure 3: Different ways to form a new subduction zone (from Stern and Gerya, 2017).

2. Where can new subduction zones form?

From our knowledge of the geological record, observations of on-going subduction, and numerical modelling (Baes et al., 2011; Leng and Gurnis, 2011; Baes et al., 2018; Beaussier et al., 2018) we think that subduction zone initiation primarily occurs through the following:

In an intra-oceanic setting through surface weakening processes

An intra-oceanic setting refers to a subduction zone forming right within the oceanic plate itself. Proposed weakening mechanisms include weakening of the lithosphere due to melt and/or hydration (e.g., Crameri et al., 2018; Foley, 2018, and references therein), localised lithospheric shear heating (Thielmann and Kaus, 2012) and density variations within oceanic plate due to age heterogeneities, where its older and denser portions flounder and sink (Duarte et al., 2016). Another mechanism proposed by Baes et al. (2018) suggests that intra-oceanic subduction can also be induced by mantle suction flow. These authors suggest that mantle suction flow stemming from either slab remnants and/or from slabs of active subduction zones can act on pre-existing zones of weakness, such as STEP (subduction-transfer edge propagate) faults to trigger a new subduction zone, thus facilitating spontaneous subduction initiation (e.g. figure 3) (Stern, 2004). The Sandwich and the Tonga-Kermadec subduction zones are often cited as prime examples of intra-oceanic subduction zone formation due to mantle suction forces (Baes et al., 2018). Ueda et al. (2008) and Gerya et al. (2015) also suggest that thermochemical plumes can break the lithosphere and initiate self-sustaining subduction, provided that the overlying lithosphere is weakened through the presence of volatiles and melt (e.g. figure 3). This mechanism can explain the Venusian corona and could have facilitated the initation of plate tectonics on Earth (Ueda et al., 2008; Gerya et al., 2015). Similarly Burov and Cloetingh (2010) suggest that in the absence of plate tectonics, mantle lithospheric interaction through plume-like instabilities, can induce spontaneous downwelling of both continental and oceanic lithosphere.

Through subduction infection or invasion

Subduction invasion/infection (Waldron et al., 2014; Duarte et al., 2016) occurs when subduction migrates from an older system into a pristine oceanic basin. Waldron et al. (2014) suggest that the closure of the Iapetus Ocean is due to the encroachment of old lithosphere into a young ocean. These authors suggests that subduction initiated at the boundary between old and new oceanic lithosphere and was introduced to the area through trench rollback. This process is thought be similar to the modern day Caribbean, Scotia and Gibraltar Arcs (Duarte et al., 2016). This suggests that the older subductions of the Pacific are invading the younger Atlantic basin, which might potentially lead to collision, orogeny and closure of the Atlantic ocean (Duarte et al., 2016).

Following a subduction polarity reversal

Subduction polarity reversal describes a process where the trench jumps from the subducting plate to the overriding one, flipping its polarity in the process (see figure 3). This can result from the arrival at the trench of continental lithosphere (McKenzie, 1969) or young positively buoyant lithosphere (Crameri and Tackley, 2015). Subduction polarity reversal is often invoked to explain and justify the two juxtaposed Wadati-Benioff zones and their opposite polarities, in the Solomon Island Region (Cooper and Taylor, 1985). Indications of a polarity reversal are also exhibited below the Alpine and Apennine Belts (Vignaroli et al., 2008). Furthermore, Crameri and Tackley (2014) also suggest that the continental connection between South America and the Antarctic peninsula has been severed through a subduction polarity reversal, resulting in the lateral detachment of the South Sandwich subduction zone.

Subduction initiation at ancient/ inherited zones of lithospheric weakness

Subduction zones can also initiate at ancient, inherited zones of weakness such as old fracture zones, transform faults, extinct subduction boundaries and extinct spreading ridges (Gurnis et al., 2004). Gurnis et al. (2004) suggest that the Izu-Bonin-Mariana subduction zone initiated at a fracture zone, while the Tonga-Kermadec subduction initiated at an extinct subduction boundary. The same study also proposes that the incipient Puysegur-Fiordland subduction zone nucleated at an extinct spreading centre.

In conclusion, we can say that subduction zone formation is a complex and multi layered process that can stem from a variety of tectonic settings. However, it is clear that our planet’s current convection style, mode of surface recycling and its ability to sustain life are interlinked with subduction zone formation. Therefore, to understand better how subduction zones form is to better understand what makes the Earth the planet it is today.

 

References:

Baes, M., Govers, R., and Wortel, R. (2011). Subduction initiation along the inherited weakness zone at the edge of a slab: Insights from numerical models. Geophysical Journal International, 184(3):991–1008.

Baes, M., Sobolev, S. V., and Quinteros, J. (2018). Subduction initiation in mid-ocean induced by mantle suction flow. Geophysical Journal International, 215(3):1515–1522.

Beaussier, S. J., Gerya, T. V., and Burg, J.-p. (2018). 3D numerical modelling of the Wilson cycle: structural inheritance of alternating subduction polarity. Fifty years of the Wilson Cycle concept in plate tectonics, page First published online.

Burov, E. and Cloetingh, S. (2010). Plume-like upper mantle instabilities drive subduction initiation. Geophys. Res. Lett., 37(3).

Cooper, P. and Taylor, B. (1985). Polarity reversal in the Solomon Island Arc. Nature, 313(6003):47–48.

Crameri, F., Conrad, C. P., Mont ́esi, L., and Lithgow-Bertelloni, C. R. (2018). The dynamic life of an oceanic plate. Tectonophysics.

Crameri, F. and Tackley, P. J. (2014). Spontaneous development of arcuate single-sided subduction in global 3-D mantle convection models with a free surface. Journal of Geophysical Research: Solid Earth, 119(7):5921–5942.

Crameri, F. and Tackley, P. J. (2015). Parameters controlling dynamically self-consistent plate tectonics and single-sided subduction in global models of mantle convection. Journal of Geophysical Research: Solid Earth, 3(55):1–27.

Duarte, J. C., Schellart, W. P., and Rosas, F. M. (2016). The future of Earth’s oceans: Consequences of subduction initiation in the Atlantic and implications for supercontinent formation. Geological Magazine, 155(1):45–58.

Dymkova, D. and Gerya, T. (2013). Porous fluid flow enables oceanic subduction initiation on Earth. Geophysical Research Letters, 40(21):5671–5676.

Foley, B. J. (2018). The dependence of planetary tectonics on mantle thermal state : applications to early Earth evolution. 376.

Gerya, T. V., Stern, R. J., Baes, M., Sobolev, S. V., and Whattam, S. A. (2015). Plate tectonics on the Earth triggered by plume-induced subduction initiation. Nature, 527(7577):221–225.

Gurnis, M., Hall, C., and Lavier, L. (2004). Evolving force balance during incipient subduction. Geochemistry, Geophysics, Geosystems, 5(7).

Leng, W. and Gurnis, M. (2011). Dynamics of subduction initiation with different evolutionary pathways. Geochemistry, Geophysics, Geosystems, 12(12).

McKenzie, D. P. (1969). Speculations on the Consequences and Causes of Plate Motions. Geophys. J. R. Astron. Soc., 18(1):1–32.

Stern, R. J. (2004). Subduction initiation: spontaneous and induced. Earth and Planetary Science Letters, 226(3-4):275–292.

Stern, R. J. and Gerya, T. (2017). Subduction initiation in nature and models: A review. Tectonophysics.

Thielmann, M. and Kaus, B. J. (2012). Shear heating induced lithospheric-scale localization: Does it result in subduction? Earth Planet. Sci. Lett., 359-360:1–13.

Ueda, K., Gerya, T., and Sobolev, S. V. (2008). Subduction initiation by thermal-chemical plumes: Numerical studies. Phys. Earth Planet. Inter., 171(1-4):296–312.

van Hunen, J. and Moyen, J.-F. (2012). Archean Subduction: Fact or Fiction? Annual Review of Earth and Planetary Sciences, 40(1):195–219.

Vignaroli, G., Faccenna, C., Jolivet, L., Piromallo, C., and Rossetti, F. (2008). Subduction polarity reversal at the junction between the Western Alps and the Northern Apennines, Italy. Tectonophysics, 450(1-4):34–50.

Waldron, J. W., Schofield, D. I., Brendan Murphy, J., and Thomas, C. W. (2014). How was the iapetus ocean infected with subduction? Geology, 42(12):1095–1098.

White, D. A., Roeder, D. H., Nelson, T. H., and Crowell, J. C. (1970). Subduction. Geological Society of America Bulletin, 81(October):3431–3432.

W.K, H. and E.H., C. (2003). Earth’s Dynamic Systems. Prentice Hall; 10 edition.

Conferences: Secret PhD Drivers

Conferences: Secret PhD Drivers

Conferences are an integral part of a PhD. They are the forum for spreading the word about the newest science and developing professional relationships. But as a PhD student they are more likely to be a source of palpitations and sweaty palms. This week Kiran Chotalia writes about her personal experience on conferences, and lessons learnt over the years.

Kiran Chotalia. PhD Student at Dept. of Earth Sciences, University College London, UK.

My PhD is a part of the Deep Volatiles Consortium and a bunch of us started on our pursuit of that floppy hat together. Our first conference adventure was an introduction to the consortium at the University of Oxford, where the new students were to present on themselves and their projects for a whole terrifying two minutes. At this stage, we had only been scientists in training for a few weeks and the thought of getting up in front of a room of established experts was scary, to say the least. Lesson #1: If it’s not a little bit scary, is it even worth doing? It means we care and we want to do the best we can. A healthy dose of fear can push us to work harder and polish our skills, making us better presenters. Overcoming the fear of these new situations takes up a lot of your energy. But it always helps to practice. In particular, I’ve always been encouraged to participate in presentation (poster or oral) competitions. Knowing that you’re going to be judged on your work and presentation skills encourages you to prepare. And this preparation has always helped to calm my nerves to the point where I’m now at the stage I can enjoy presenting a poster.

Regular work goals that crop up in other professions are often absent, especially when we’re starting out.  The build-up to a conference acts as a good focus to push for results and some first pass interpretations. At the conference itself, it makes sure people come to see your poster and you can start to get your face out there in your field. Lesson #2: Sign up for presentation competitions. AGU’s Outstanding Student Presentation Award (OSPA) and EGU’s Outstanding Student PICO and Poster (OSPP) awards are well established. At smaller conferences, it’s always worth asking if a competition is taking place as, speaking from experience, they can be easily missed. They also give you a good excuse to practice with your research group in preparation, providing the key component of improving your presentation skills: feedback. Lesson #3: Ask for feedback, not just on your science but your presenting too. If you’re presenting to people not in your field, practice with office mates that have no idea what you get up to. By practicing, you can begin to find your style of presenting and the best way to convey your science.

Me, (awkwardly) presenting my first poster at the Workshop on the Origin of Plate Tectonics, Locarno.

Sometimes, you’ll be going to conferences not only with your fellow PhD students, but also more senior members. They can introduce you to their friends and colleagues, extending your network, more often than not, when you are socialising over dinner, after the main working day. Lesson #4: Keep your ear to the ground. These events provide a great opportunity to let people know you are on the hunt for a job and hear about positions that might be right for you. At AGU 2018, I became the proud owner of a ‘Job Seeker’ badge, provided by the Careers Centre. It acted as a great way to segue from general job chat into potential leads. A memento that I’ll be hanging on to and dusting off for conferences to come!

One of the biggest changes to my conferencing cycle occurred last year after attending two meetings: CIDER and YoungCEED. Both were workshops geared towards learning and research, with CIDER lasting four weeks and YoungCEED lasting a week. Lesson #5: Attend research specific meetings when the opportunity arises. Even if they don’t seem to align with your research interests from the outset, they are incredible learning opportunities and a great way to expand your research horizons. By attending these meetings, the dynamic of my first conference after them shifted. There was a focus on catching up with the collective work started earlier in the year. Whilst the pace was the most exhausting I’ve experienced thus far, it was also the most rewarding.

Between all the learning and networking, faces start to become familiar. Before you know it, these faces become colleagues and colleagues quickly become friends. In our line of work, our friends are spread over continents, moving from institution to institution. They tend to offer the only opportunity to be in the same place at the same time. This also results in completely losing track of time and catching up into the early hours of the morning, so the next lesson is more subjective. Lesson #6: Know your limits. Some can stay out until 4am and rock up at the 8.30am talk. I wish I was one of these people but I have a hard time keeping my eyes open past 12.30am. Whatever works for you!

Me, presenting my most recent poster at AGU 2018 with my job seeker badge!

After the conference finishes, you are often in a place that you’ve never visited before. Lesson #7: Have a break. If you can, even an extra day or two of being a tourist is great treat after a hectic build-up as well as the conference itself. If staying for a mini holiday post-conference is not an option, make sure you take some time when you get home to rest and readjust before you get back to work and start planning for the next one.

Last but not least, Lesson #8: Don’t forget to have fun. The stress surrounding conferences and your PhD in general can at times be all consuming. Remember to enjoy the small victories of finally getting a code to run or finding time on the SEM to analyse your samples. At conferences, enjoy being surrounding scientists that are just starting out and the seasoned professionals with a back catalogue of interesting stories. And if you’re lucky enough to be at a conference somewhere sunny, make sure to get outside during the breaks and free time to soak up some vitamin D!

The Shanghai skyline after the Sino-UK Deep Volatiles Annual Meeting at Nanjing University.