Geology & Geophysics AGU News

Bachmann and Yizengaw Receive 2018 Joanne Simpson Medal

Olivier Bachmann and Endawoke Yizengaw were awarded the 2018 Joanne Simpson Medal at the AGU Fall Meeting Honors Ceremony on 12 December 2018 in Washington, D. C. The medal is for “significant contributions to the Earth and space sciences by an outstanding mid-career scientist.”


Citation for Olivier Bachmann

Olivier Bachmann, 2018 Simpson medalist
Olivier Bachmann

It is my great pleasure to introduce one of the two inaugural recipients of the Joanne Simpson Medal, Olivier Bachmann. Olivier has made important contributions to the field of volcanology using a combination of field work, geochemistry and petrology, geochronology, and physical modeling. It is this ability to combine various disciplines and address fundamental questions regarding the physical and chemical evolution of magmas that is the hallmark of Olivier’s research.

Olivier’s intellectual curiosity and boundless energy caught the attention of Michael Dungan and Peter Lipman (at the U.S. Geological Survey) as he started a Ph.D. on the eruption sequence of the Fish Canyon magma body (Pagosa Peak Dacite and the Fish Canyon Tuff). Integrated over his graduate studies, Olivier spent over a year in the field in southern Colorado, mapping and sampling these units. The publications that resulted have had a deep impact and opened new perspectives in our understanding of the systems that feed caldera-type eruptions. Olivier’s early research also highlighted the importance of magmatic mushes in controlling the physicochemical evolution of magma reservoirs.

As Olivier established himself as a leader in petrology and geochemistry of silicic magmas, he decided to develop a new and complementary set of skills, a courageous choice that is typical of Olivier’s mindset. He joined forces with George Bergantz (University of Washington) to develop physical models for magmatic processes and published two landmark papers on the generation of high-silica rhyolites and the reactivation of magmatic mushes preeruption. Olivier’s ability and willingness to push beyond the boundaries of his own field are a recurring theme; the same spirit led him later to take an active role in the Imaging Magma Under St. Helens (iMUSH) project, whose aim is to combine petrology and geophysics to better constrain the state of active volcanic centers in the Cascades.

Since 2012, Olivier has been the chair of the Institute of Geochemistry and Petrology at Eidgenössische Technische Hochschule (ETH) Zürich. His group is working on a variety of exciting and creative projects combining magmatic petrology, geochemistry, geochronology, and numerical modeling. On a more anecdotal note, Olivier holds now another distinction: He has taught the principles of volcanology in three different languages. Olivier’s enthusiasm and passion, as well as his unfaltering support, have had a deep influence on the career of many researchers in and outside his own group. I am proud to present my dear friend and inspiring collaborator as a recipient of the Joanne Simpson Medal.

—Christian Huber, Brown University, Providence, R.I.



Thank you, Christian, for your nomination, your kind citation, and your boundless support over all these years. Clearly, without you, my route would have followed a much less exciting path, and your amazing creativity, breadth, and understanding of the laws that control our fates (in science and other fields) have been, for me, powerful sources of inspiration. Being able to work with a such a friend is a chance I truly cherish.

I am, of course, deeply honored to receive such a medal, remembering the remarkable achievements of a woman and celebrating diversity within AGU. I am indebted to the letter writers and committee of this honors program, who make a tremendous effort to encourage our community to become better.

As Christian mentions in his citation, I am interested in coupling different fields to try and shed light on interesting aspects of our planet. In this endeavor, collaboration is key, and much of what I have been able to achieve over the years relies on people who have given me their trust and worked with me. Obviously, there are too many people I should thank for this list, but allow me to single out a few. First, I send my deepest appreciation to my mentors over the years, first at the University of Geneva (Mike Dungan), at the U.S. Geological Survey (Peter Lipman), and at the University of Washington (George Bergantz). Their support and the motivating atmosphere they fostered were key in the first steps of my career. I also want to thank all the students and postdocs (in particular, in the postdoc crowd, Chad Deering, Andrea Parmigiani, Wim Degruyter, Ozge Karakas, Ben Ellis, Matthieu Galvez, and Jörn Wotzlaw) who have shared their enthusiasm for magmas and volcanoes with me over the years; the working atmosphere in the group, particularly these last few years at ETH, has been fantastic, and their energy and creativity have been some of the most fulfilling rewards I have received.

As Joanne Simpson reputedly said, combining a career in academia and strong family ties is an amazing challenge; I am more than indebted to my own house team, my parents, my sister, my wife, and my three beautiful children, for turning this challenge into an everyday pleasure. This medal is for my dad, in memory of his boundless tolerance, enthusiasm, and humility.

—Olivier Bachmann, Eidgenössische Technische Hochschule Zürich


Citation for Endawoke Yizengaw

Endawoke Yizengaw, 2018 Simpson medalist
Endawoke Yizengaw

Endawoke Yizengaw is the epitome of the AGU Joanne Simpson Medal. He has demonstrated scientific excellence in space science research; performed active outreach to the international space weather community; and dedicated strong commitment to his colleagues, students, and postdocs.

I’ve come to know Endawoke not only for his scientific prowess but also for his life story, how he became a great scientist and a great man after very humble beginnings in Ethiopia. Endawoke was born the youngest child of a large Ethiopian family in a rural village where herding and animal care were his primary activities. School was attended by walking long distances every day. His brilliance was recognized by his teachers, who encouraged him (and his family) to stay in school and later to attend university. He obtained a B.S. in physics at Addis Ababa University, a M.S. in atmospheric physics from the University of Tromsø, and a Ph.D. in space physics from La Trobe University in Australia. Since then, he has done much to advance space physics exploration with a keen interest to develop infrastructure and education in space science in developing countries. Considering his humble beginnings, these are admirable accomplishments.

Endawoke has contributed significantly to the scientific literature on the complexities of ionospheric electrodynamics. He has published scores of high-impact papers using multiple instrument techniques from ground and space. Two of his early papers were selected for the cover of Geophysical Research Letters. One of those papers proved a long-standing conjecture that the ionospheric trough is the signature of a boundary in the magnetosphere. More recent publications describe work where he used ground-based measurements to demonstrate that dayside electrodynamics display not only temporal and seasonal variations but also very strong gradients versus longitude. In addition, Dr. Yizengaw developed the African Meridian B-field Education and Research (AMBER) network of magnetometer instruments in more than 10 countries.

Besides his scientific contributions, Endawoke has played a vital role in the expansion of space science education and research in developing countries. He participates in the International Space Weather Initiative (ISWI), was active in the International Heliophysical Year (IHY) program, and has performed scientific outreach programs for young scientists in the United States and developing nations. He has coconvened conferences and schools in Africa, including an AGU Chapman Conference and a number of ISWI and IHY programs. Endawoke has also mentored postdocs and Ph.D. students who have gone on to develop research programs in developing countries.

To summarize, Dr. Yizengaw is an eminent mid-career scientist with attributes emphatically worthy of the AGU Joanne Simpson Medal.

—Patricia H. Doherty, Boston College,  Mass.



Thank you, Pat, for those overly kind words. It is my great honor to receive this award. The fortunate start of my career has depended intensely on the support of family members. I grew up as the youngest of seven children in my family in Amber, a village in northwestern Ethiopia. Although my primary task as a child was to look after the family’s cattle, I joined the nearby elementary school through the influence of my grandfather. However, my parents envisioned me taking over the family farm and eventually forced me to stop my education at grade 4. Two years later, two policemen came to our home with a letter from the principal of my school. It was a warning letter that urged my father to send me back to school or face a legal penalty. It was shocking news for my parent but for me a miraculous gift. Later, I learned that it was my brother Gelaye Leyikun, an elementary school teacher, who used his friend (the principal) to force his own father and pave my way back to school.

My interest in science began in middle school, and I became interested in space science after I listened to a radio interview with an Ethiopian aerospace scientist. It motivated me to search for opportunities around the world to study space science, and I joined Tromsø University in Norway for M.Sc. studies and La Trobe University in Australia for my Ph.D. degree. In May 2004 I joined the University of California, Los Angeles, as a postdoc with Mark Moldwin, who showed me all the necessary tools to be a good scientist and poured everything he had into me to boost my visibility in the space science community. I joined Boston College in 2009 and became fortunate to work very closely with very talented scientists. Specifically, I am indebted to Pat Doherty, our director, for her enthusiastic support of my research and international outreach activities. I am also so grateful to the funding agencies that made my dream a reality.

Last, but not least, this would have not been possible without the love and friendship of my wife, Yemisirach, and hugs from my kids, Hanna and Yoseph. There are also so many more family members, friends, and colleagues I’d like to thank but cannot name. Most importantly, I simply would not be here without the enthusiastic support of my late parents and brother (Gelaye Leyikun), who nurtured my academic success not only to be a scientist but also to see the world at large and to imagine and research even far from the horizon.

—Endawoke Yizengaw, Boston College, Mass.

Citation: AGU (2019), Bachmann and Yizengaw receive 2018 Joanne Simpson Medal, Eos, 100, Published on 04 January 2019.
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