Tectonics and Structural Geology

Remembering Janos Urai – A master of all scales

Remembering Janos Urai – A master of all scales

Cover illustration highlighting Janos’ seminal 1986 Nature paper on water weakening of rocksalt. The image features one of Janos’ first attempts to decorate rocksalt microstructures by means of gamma-irradiation.

As many will know, on Sunday, 28 May 2023, one of the most prominent, energetic and valued members of the Tectonics and Structural Geology community, Emeritus Professor Janos Urai, was lost in a tragic climbing accident in Belgium. Here we remember Janos for the amazing scientist that he was and for the huge legacy that he has left, in the form of his own transformative contributions and the inspiration that he magically passed on to colleagues and students alike.

Janos graduated Cum Laude with Prof. Henk Zwart and Gordon Lister at Utrecht in 1983 with his PhD thesis on ‘Deformation of wet salt rocks’, which revolutionized interpretation of recrystallization microstructures in salt and other rocks. In 1989, Janos moved to Shell Research (Rijswijk, NL), where his microscale approach led to major advances in understanding claystone consolidation swelling and sealing, as well as fibrous vein filling.

In 1996, Janos became Professor of Geology and Endogene Geodynamics at RWTH Aachen University, where he remained until retirement in 2020. At Aachen, Janos exploded into researching a vast range of topics at multiple scales. He built analogue (sandbox) deformation systems for studying faulting. He conducted field studies on fault tectonics, shale-slate deformation, mullion formation, fluid overpressuring, salt diapirism and more. Alongside his position in Aachen, in 2006 Janos became Professor and Dean at the German University of Technology in Oman (Muscat). There he found new challenges in the ophiolite and carbonate sequences, touching on almost every aspect of Omani tectonics and structural geology, again at every scale. At RWTH Aachen, Janos also co-founded Microstructures and Pores GmbH (MaP).

Janos Urai was a unique individual. He was a brilliantly creative researcher, motivated by insatiable curiosity and filled with drive to get answers. His enthusiasm and ability to make the dynamics of microstructure and mountain building “come alive” was inspiring to all. Below, we have gathered memories by colleagues who worked with Janos, providing perspectives from MSc students, PhD researchers, and MaP collaborators. We hope these will provide a fitting tribute to an amazing scientist, mentor and person – a master of all scales indeed.

Boudins from Naxos. Janos convinced the quarry to cut many slices of various sizes which have since found their way to offices and labs, along with the challenge to explain the formation of these structures.
Picture by Susanne Buiter.

Chris Spiers – Emeritus Professor, HPT Laboratory, Faculty of Geosciences, Utrecht University, the Netherlands

Susanne Buiter – Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences and Tectonics and Geodynamics, RWTH Aachen, Germany


Science and mountains
Journey to knowledge and truth
Echter Mensch and friend

Scientific literature affords a record of what a person accomplishes over a lifetime, but it falls to individuals to relate stories about how those accomplishments were achieved. As an experimentalist, Janos brought imagination and creativity in the laboratory to problems of how the Earth works within the constraints of laboratory machines. Compromises and trade-offs, balanced to achieve the greatest advancement. And so it was in his life, too, striving to improve his place in the world while also inspiring students, colleagues, and friends to strive for more than their best. Experiencing the exhilaration of nature in the mountains, challenging himself physically and spiritually. Driving from Aachen to Maastricht after a day wrangling over a paper and stopping to buy cherries from his favourite farm to share in his garden. We gave each other opportunities to practice humility in science and sports. I will miss his intense interest in others and the joy he carried with him. I hope that many who read this have their own memories of experiences with Janos and the way he lived life that you will cherish and share with those you hold dear.

Peter Vrolijk, Adjunct Professor, New Mexico Institute of Mining and Technology, USA, retired from ExxonMobil Upstream Research Company


Janos L. Urai – an Exceptional Teacher and Scientist

Janos was renowned for his high standards in his courses, and succeeding in his exams required a lot of effort and dedication. His tasty experiments in Greek yoghurt, such as illustrating wing cracks, sigma and delta clasts by stirring marmalade blobs or steady-state deformation by mixing cereal into it, left a lasting impression on his students. Janos exhibited boundless creativity in explaining geological phenomena, making the learning experience truly memorable. During field trips, we sometimes struggled to keep up with his brisk pace as he proved to be fitter than most students. However, he always made time for personal conversations and offered valuable advice during dinner gatherings. As one of the most family-supporting professors, Janos encouraged the pursuit of a scientific career while starting a family, proving to be an inspiring mentor. In the role of a “doctor father”, Janos took care of his PhD students like a paternal figure. Even though communication could be challenging, he provided unwavering support during difficult times and motivated us when we felt lost or lacked enthusiasm throughout our doctoral studies. We were lucky to work with someone, who shared the same fascination for microstructures, especially in blue salt. His approach to studying how mountains move and his stream of shear endless ideas (geology pun intended) was inspiring and infectious. Janos Urai truly had a remarkable impact on his students’ lives as both a mentor and a scientist.

Julia Schmitz and Jessica Barabasch, Tectonics and Geodynamics, Division of Earth Sciences and Geography, RWTH Aachen, Germany


Janos Urai – Doktervater and much more

I can still remember both the very first conversation, by phone, and the first meeting with Janos because he had such funny answers to my, rather stupid, questions. From the beginning (early 2010) we got along well, even though the meetings were scarce and particularly unpredictable, especially in the first few years. It was always good to have a few nice BIB-SEM pictures ready and then Janos could spend an enthusiastic hour talking about pores, applications and new issues. And then at the end of the conversation I still had no answer to my question and I could wait for another month or so. Nevertheless, I was able to successfully complete my PhD and the conversations became more intensive, and in particular how we could further apply the BIB-SEM technique, for example in the form of a company. Together with Joyce Schmatz, this ultimately resulted in MaP – Microstructure and Pores GmbH, for which Janos often came up with new projects or proposals. In the last few years, we had frequent contact, almost daily, and the conversations became more personal and ideas continued to flow. Sometimes crazy, but always creative or challenging. Unfortunately, you are no longer here and a huge source of inspiration has been lost. Janos, one of a kind, I will miss you enormously.

Janos and Jop sharing a piece of cake after a successful meeting, 2019. (Credit Jop Klaver)

Jop Klaver – Microstructure and Pores GmbH, Aachen, Germany


Janos Urai – the integrative geoscientist

I was lucky to be one of the first students of Janos in Aachen back in 1996. He was an extraordinary motivating teacher, using creative ideas to illustrate key structural geological processes. Chocolate bars are helpful to illustrate joints (dark chocolate works best), computer card decks to show kink-band folding, and the edelweiss plant likes to grow on calcite bands (a fact he earlier exploited with Cees Passchier). He also always strove to bring quantitative aspects in his teaching and it was thus no surprise that the textbooks of Ramsey (structural geology) and Twiss & Moores were the main points of reference. For the students, this wasn’t always easy sailing, as he suddenly made us work much harder than we were used to. The most demanding and inspiring exercises at the time consisted in a geological map with a few hints and a simple question: where should one drill to find the most promising reservoir? Self-organisation and late-nighters were required to make the 7-day deadline (and not everyone was happy about that…). I guess it was not an easy time for him either, as I recall that he once worked all night to finish a class on dike propagation, only to discover that most students were on an excursion.

My own life took a different turn shortly afterwards, and I moved to ETH to focus on computational geodynamics. We did stay in touch, though, and started collaborating again in 2016 on a multi-university project (PERMEA) on the permeability of fractured rocks. Later (mostly after his retirement), we started an intense collaboration on salt tectonics, focusing on the long-term safety of salt cavern abandonment, and the potential use of salt to store hydrogen or to host nuclear waste repositories. Tackling such questions requires a truly multi-disciplinary approach and Janos was a master in coordinating this, which made him a unique and versatile geoscientist.  His work will continue but he will be deeply missed.

Boris Kaus – Institute of Geosciences, Johannes-Gutenberg-University Mainz, Germany


For those who wish to share their condolences or memories of Janos, please go to Janos’ remembrance page.

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Hannah Davies is currently a Posdoctoral researcher at GFZ Potsdam, Germany. Her research is focused on modelling million year time scale landscape evolution and its relationship to other components of the Earth system

1 Comment

  1. Nice classmate at Leiden, just before Geology was moved to Utrecht at the end of the 1970’s. He recently offered assistance to calculate length of active Riedels just below a proposed new hospital in Costa Rica.

    We all shall miss him, but his example as very collaborative colleague remains.

    Allan López


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