Researchers from the University of Tokyo have made significant strides in understanding the nature and role of subsurface fluids, including water, in relation to earthquakes and volcanic activities. Their latest study introduces innovative methods that suggest heavy rainfall may contribute to seismic events. This breakthrough could enhance early warning systems and improve seismic activity models, potentially saving lives during disasters.
The research team, led by Professor Takeshi Tsuji from the Graduate School of Engineering, emphasizes the importance of advanced seismic imaging techniques. According to Tsuji, “Our latest paper using advanced seismic imaging shows, for the first time, how deep volcanic fluids, such as water, in their high-pressure supercritical state, can become trapped, migrate and undergo phase changes that influence earthquakes.”
By applying machine learning to seismometer data, the researchers achieved a detailed mapping of earthquake distribution and mechanisms. This work focuses particularly on the brittle-ductile transition zone, where geological structures shift from being seismically active to largely inactive. The seismic approach reveals these systems in unprecedented three-dimensional detail, providing insights that earlier low-resolution surveys could not.
Supercritical fluids, which possess characteristics of both liquids and gases due to their high pressure and temperature, play a crucial role in this research. They can easily flow like gas but store and transfer significant amounts of heat like a liquid. As these fluids move through various geological environments, they can rapidly heat areas, altering the behavior of both the rocks and the magma beneath.
The research highlights an intriguing connection between rainfall and seismic activity. Tsuji notes, “When heavy rain falls, the groundwater level rises, increasing pressure in cracks and faults deep below. If those faults are already close to breaking, this added pressure can trigger earthquakes.” In regions with active volcanoes, where the crust is weakened by high-pressure fluids, this effect can be particularly pronounced.
The study not only aims to improve disaster prediction but also seeks to identify areas rich in geothermal energy. Japan, a country with significant geothermal potential, has yet to fully exploit this resource. The project originated to find reliable drilling targets for accessing supercritical water reserves essential for geothermal power generation.
With their new methodology, Tsuji and his team successfully identified fluid pathways, reservoirs beneath sealed layers, and fractures that allow fluids to escape. “Underground supercritical water contains vast thermal energy, making it an incredibly promising renewable resource for the future,” Tsuji stated. Importantly, because this energy is drawn from deep reservoirs, it does not disrupt existing surface hot spring systems, which is a major concern for geothermal projects in Japan.
Despite these advancements, challenges remain. The primary obstacle to harnessing supercritical geothermal energy lies in drilling technology. These fluids exist at great depths under extreme conditions, necessitating specialized equipment and techniques for safe and efficient extraction. As the research progresses, the focus will shift to developing practical well designs that can make this energy source viable.
Overall, the findings from the University of Tokyo team represent a vital step forward in both understanding the geological processes underlying seismic events and tapping into sustainable energy sources. As the scientific community continues to enhance its models and observations, the potential for improved disaster preparedness and renewable energy exploitation becomes increasingly attainable.
