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Invention Revolutionizes Underground Mapping

Hans Malehmir’s groundbreaking invention is offering scientists and engineers a detailed look at what lies beneath the surface of the Earth. This innovative tool has been deployed worldwide for diverse projects—from large-scale road and tunnel construction in Sweden to earthquake risk assessments in Seoul, South Korea, and even evaluating potential sites for carbon storage in Denmark. In recognition of this remarkable contribution, geophysicist Alireza Malehmir has been awarded the prestigious Hjärnäpplet prize (Uppsala University, Sweden).

His creation, a seismic landstreamer system, has become a globally recognized solution for complex underground mapping challenges. “I see this award as recognition not just for me, but for our entire research team,” Malehmir said. “Many people have invested time and effort into transforming this concept into a product that now plays a crucial role in solving societal problems.”

Mapping the Underground with Precision

The principle behind the seismic landstreamer system is simple yet powerful: seismic waves travel at different speeds and intensities depending on the materials they pass through. By analysing how these waves move through the Earth, scientists can create detailed images of underground structures, helping assess the stability of the ground.

Traditional seismic methods involve anchoring sensors directly into the ground, a slow and labour-intensive process often impractical in noisy urban environments. Malehmir sought to overcome these limitations by designing a mobile system capable of rapidly surveying large areas.

The Journey from Concept to Global Impact

“In 2010–2011, we realized Sweden was gearing up for several major infrastructure projects,” Malehmir explained. Among these was the Förbifart Stockholm bypass project, a massive road and tunnel system. “We knew these projects would face significant challenges, especially considering past issues with tunnel construction through the Hallandsåsen ridge.” Accurate ground mapping became essential to avoid similar setbacks.

Malehmir envisioned a mobile solution: a seismic landstreamer consisting of interconnected digital sensors mounted on sleds. These sensors pick up seismic waves generated by controlled impacts on the ground, such as a heavy thud. The data is synchronized using GPS, enabling precise mapping of underground conditions.

Foto: Alireza Malehmir

By 2013, Malehmir’s team had developed their first prototype and tested it during the initial excavation for the Förbifart Stockholm tunnels. Despite using only 20 sensors, the results exceeded expectations. “We worked at night to avoid traffic interference, and the results were surprisingly good. Everyone was thrilled,” Malehmir recalled.

A Global Tool for a Global Need

The system’s success in Sweden attracted international attention. It was later deployed during the construction of the double tunnel in Varberg, where it again proved its worth by providing accurate ground assessments. Over time, the system has been refined to increase efficiency.

“In the beginning, we could only map about 400 meters in a day,” Malehmir said. “But last year (2023) in Denmark, we managed three kilometres per day—a huge improvement.”

One of the most significant applications of the landstreamer system took place in South Korea. There, it was used to map fault lines beneath major cities, including Seoul, to assess earthquake risks.

“After the Fukushima earthquake, South Korea became concerned about its older buildings in urban areas,” Malehmir explained. “If a similar event occurred inland, they needed to be prepared. Our system helped provide the data they needed to plan for such scenarios.”

The Future of Seismic Technology

Malehmir founded Nordic Geophysics in 2018 to commercialize the landstreamer system further. To date, three systems have been produced, one of which has been sold to Denmark. Interest is also growing in South Africa.

The company is already working on the next-generation landstreamer, which will run on battery power instead of electric cables, making it even more flexible and practical. “We’ve patented the new design, and a contract has already been signed with a manufacturer,” Malehmir said, hinting at even greater potential for this game-changing innovation.

Malehmir’s work demonstrates the power of innovation in addressing real-world challenges. From safer tunnels to earthquake preparedness, his seismic landstreamer is proving that science doesn’t just explore—it builds a better future.

Originally published by Uppsala University, written by Åsa Malmberg. Translated and rewritten by Christer Granlycke, forumNordic. For further info: Uppsala University

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