Imagine peering into Earth as if it were a patient undergoing a CT scan. That's essentially what Danish geophysicist Hans Thybo does, except that instead of X-rays, he uses seismic waves and other advanced imaging techniques to explore the planet's deep secrets.

As a full-time distinguished professor at the Chinese Academy of Geological Sciences (CAGS) and a member of both the Danish Royal Academy of Sciences and the European Academy of Sciences, Thybo has made groundbreaking contributions to our understanding of Earth's structure. He discovered the mid-lithospheric discontinuity and was the first to identify deep structures linked to over 1.5 billion years of plate tectonics. With more than 60 international projects under his belt and a long-standing collaboration with Chinese scientists, Thybo's work spans continents and minds.

A curious mind's journey

Thybo's scientific journey began in the classroom of a passionate natural history teacher who taught him how to observe nature closely. Yet, despite his early interest in biology and geology, he initially pursued mathematics and physics, acquiring a PhD in theoretical seismology. It wasn't until his postdoctoral research that he applied this theoretical knowledge to image Earth's crust and lithosphere, which he calls "the wonders of tectonics."

"I've made a long journey regarding scientific interest," he says reflectively. "My experience tells me that science improves when we maintain a broad overview while mastering technical skills."

To many, studying Earth's interior might seem abstract or even fantastical. But Thybo emphasizes its "profound societal importance": "All geoscience ultimately has importance for society." His imaging techniques are not just academic exercises. They are tools used to locate natural resources, understand earthquake mechanisms, and reduce the risks of volcanic eruptions.

"Imaging fault planes helps us understand earthquakes," he explains. "And the same methods used to study one geological phenomenon often lead to insights into another. That's the beauty of science, it connects everything."

Power of international collaboration

Having initiated over 60 large-scale international projects, Thybo is a great collaborator. His secret? Ask the right questions and find the right people.

"Geological processes don't stop at national borders," he says. "International collaboration is essential." For him, successful global projects hinge on creating a shared identity among the team members. "When collaborators feel they belong to one large team with a common goal, they can overcome any challenge."

His latest endeavor, EarthProbe (formerly known as Earth CT), embodies this collaborative spirit. Initiated in 2017 and inspired by China's SinoProbe program, EarthProbe aims to bring together scientists from every continent to address major geoscientific questions through integrated geophysical, geological, and geochemical studies.

"The pandemic was frustrating. We couldn't meet in person," he admits. "But it gave us time to rethink and plan better." Now, EarthProbe is ready to launch a new organizational framework, enabling large-scale, cross-continental projects that will train a new generation of scientists and deliver insights with global relevance.

Thybo speaks highly of his experience in working with CAGS. "CAGS is a wonderful place for doing research," he says. "The facilities are top-notch, and the funding for SinoProbe is unprecedented on an international scale."

He also praises the focus and efficiency of Chinese scientists. "They're very well prepared and come to discussions with clear ideas," he observes. Over the past two decades, he has witnessed a dramatic shift in China's scientific landscape from publishing mostly in domestic journals to leading in international publications. "It's a fascinating transformation," he adds. "China's scientific community has taken a huge step forward."

Building bridges

Beyond research, Thybo values mentorship deeply. He has personally mentored many Chinese PhD students, fostering a culture of mutual trust and intellectual curiosity.

"I treat all my students the same way, whether they're from Europe or China," he says. "It's only when a young colleague finds something out for themselves that the learning lasts."

"Each student is unique. Mentoring is about building on their strengths and asking questions that help them reach their conclusions," he says. For him, mentoring "must always be in a pleasant atmosphere of mutual trust." He still maintains contact and collaboration with all his former Chinese students who are now playing an active role in sci-tech field.

Even during the pandemic, when regular travel came to a halt, Thybo maintained weekly virtual meetings with his former students across China. Today, those meetings continue to maintain the academic bond.

As EarthProbe gains momentum and CAGS continues to push the boundaries of deep Earth exploration, Thybo remains optimistic. "I'm confident that this new organization will allow us to initiate new large-scale integrated geoscientific projects on all continents," he says.

The CAGS also contributed to this article.