How did the Chile earthquake of 2010 create a tsunami?

The 2010 Chile earthquake generated a tsunami due to the violent tectonic activity occurring along the boundary between the South American Plate and the subducting Nazca Plate.1

As these two plates converged, the immense stress caused rocks to shatter along the fault line. This geological process forced a significant portion of the seabed to thrust upward. Because this movement occurred beneath the Pacific Ocean, the sudden vertical displacement of the seafloor pushed the massive volume of water above it, triggering the tsunami.12

Once the initial disturbance occurred, the resulting waves traveled across the ocean at speeds reaching nearly 450 miles (725 km) per hour, eventually inundating coastal areas in Chile and impacting regions across the Pacific.1