A seismic joint is a flexible gap or space designed in buildings and structures to absorb and dissipate energy during an earthquake. This feature allows different parts of a structure to move independently, reducing the risk of damage. Seismic joints are crucial in areas prone to seismic activity, as they help maintain the integrity of the overall structure. These joints are typically made from materials that can withstand significant stress and movement, such as rubber or specialized polymers. Properly designed and installed seismic joints can enhance the safety and longevity of structures, making them essential in modern engineering practices, especially in regions near tectonic plates like the San Andreas Fault.