An earthquake is caused by the sudden release of built-up energy along fault lines in the earth's crust. Most earthquakes occur along plate boundaries and fault lines, especially around the Pacific Ring of Fire. Earthquakes can cause tremendous damage through ground shaking and secondary effects like tsunamis. Recent major quakes in Nepal and Japan killed over 9,000 and led to widespread destruction. While earthquakes can't be prevented, communities can take steps to minimize damage by strengthening buildings and infrastructure and preparing emergency plans.