Tracking Energy in Laboratory Earthquakes

In a groundbreaking scientific step, geologists at the Massachusetts Institute of Technology (MIT) have traced the energy released during laboratory earthquakes, which are carefully induced miniature models of natural earthquakes in a controlled lab environment. For the first time, they have managed to determine the complete energy budget of these earthquakes and how it is distributed among heat, tremors, and fractures.

Understanding the Energy Budget in Laboratory Earthquakes

The study revealed that only about 10% of the laboratory earthquake’s energy results in physical tremors, while less than 1% goes into breaking rocks and creating new surfaces. The majority of the earthquake’s energy, averaging 80%, is used to heat the area around the earthquake’s epicenter. Researchers observed that a laboratory earthquake could cause a temperature rise sufficient to melt surrounding materials and temporarily turn them into molten liquid.

These findings suggest that the energy budget of an earthquake heavily depends on the deformation history of the area, which refers to the amount of movement and change in rocks due to previous tectonic activities. These changes affect the material properties of the rocks and, to some extent, determine how they slip during earthquakes.

Geological Impacts and Scientific Collaboration

Daniel Ortega-Arroyo, a graduate student in the Department of Earth, Atmospheric, and Planetary Sciences at MIT, explained that “the deformation history, or what the rocks remember, significantly influences the destructiveness of an earthquake.” He points out that this history impacts many physical properties of the rocks and dictates, to some degree, how they slide.

Laboratory earthquakes serve as simplified models of what occurs during natural earthquakes. In the future, these findings could assist seismologists in predicting the likelihood of earthquakes in areas prone to seismic events. For instance, if scientists have an idea of the tremors generated by a previous earthquake, they might be able to estimate how the earthquake’s energy also affects deep underground rocks by melting or fracturing them.

Techniques Used in the Study

To gain insight into how earthquake energy is distributed and how the energy budget might affect earthquake risks in a specific area, researchers turned to the lab. Over the past seven years, the research team at MIT has developed methods and tools to simulate seismic events on a microscopic scale, attempting to understand how earthquakes occur on a larger scale.

The team generated miniature laboratory earthquakes that mimic the seismic slip of rocks along fault zones. They used small samples of granite, which represent the rocks in the seismic layer, the geological region in the continental crust where earthquakes typically originate.

Conclusion

This study provides a comprehensive perspective on the physics of seismic collapses in rocks, enhancing our understanding of earthquakes and contributing to the improvement of current seismic prediction models. Thanks to these experiments, we can now look forward to better strategies for mitigating natural risks associated with earthquakes.