Core Insights - Researchers from the University of Southern California have developed a visual model to track the evolution of micro-contact points on fault surfaces during seismic cycles, revealing the physical mechanisms behind the slow accumulation of tectonic stress and rapid earthquake rupture [1][2] - The study indicates that the actual contact area between rough surfaces, which is only a small fraction of the total surface area, is a key variable controlling seismic behavior [1] - The findings suggest that monitoring physical properties related to the real contact state of faults could become crucial for short-term earthquake warning systems [2] Group 1 - The research utilized transparent acrylic materials to visualize the real-time process of earthquake rupture in the laboratory [1] - High-speed cameras and optical measurements were employed to track changes in LED light transmission corresponding to variations in contact points during simulated earthquakes [1] - Approximately 30% of the contact area was observed to disappear within milliseconds during rapid rupture, contributing to the occurrence of earthquakes [1] Group 2 - The analysis of 26 different simulated earthquake scenarios demonstrated a correlation between rupture speed and the energy required for fracture, aligning with predictions from linear elastic fracture mechanics [2] - The computer simulations successfully replicated both slow and fast earthquake processes, showing high agreement with predicted outcomes across multiple dimensions, including rupture speed and stress drop [2] - The study reveals a long-hidden connection between empirical "state variables" used in standard earthquake models and the actual contact area between fault surfaces, providing a physical explanation for this critical mathematical variable [2]