It is with immeasurable sadness to share that Dr. Hannes Leetaru passed away on May 31, 2023. 

"Hannes was perhaps the most committed scientist that I have encountered to the ideals, goals, and philosophy of what a geological survey embodies and the impact that it has on both the scientific community and the social community that it directly and positively impacts," said Dick Berg, State Geologist and Director of the Illinois State Geological Survey (ISGS).

Leetaru was a senior petroleum geologist for more than 33 years and head of Subsurface Energy Resources at ISGS. This month Hannes was completing his term as president of the American Association of Petroleum Geologists (AAPG) Division of Environmental Geosciences (DEG) and has twice received an AAPG Certificate of Merit. In 2012 he received the A.I. Levorsen Memorial Award. 

"It was indeed my pleasure getting to know Hannes during the past year. His life and the legacy of his research will forever live on through the ISGS and PRI. He and his family will be in my thoughts," said Praveen Kumar, Executive Director of the Prairie Research Institute (PRI).

His final column as DEG president appeared in the June AAPG Explorer, published exactly at the time of his passing. In it, he wrote of the critical importance of carbon capture for both the industry and the profession and outlined the progress and initiatives DEG took under his leadership to address the issue.

“It’s been an exciting year at the Division of Environmental Geosciences,” he wrote. “Carbon capture, utilization, and storage, along with the problems and opportunities presented by orphan wells, have both been hot topics in the industry … and will continue to be the focus of the DEG.”

He began his career as an advanced exploration geologist with Getty Oil (1978) and as a senior geologist for Union Pacific Resources (1984), both in Houston. He received his bachelor’s degree in geology from the State University of New York at Fredonia, his master’s degree in geology from Syracuse University, and his doctorate in geology from the University of Illinois Urbana-Champaign.

Hannes will be truly missed as a leader at ISGS, a true friend, and a colleague to all that he touched. Our constant thoughts are with his wife, Marilyn, and son, Kalev.