What is the Ring of Fire?

The Ring of Fire is an area of particularly intense tectonic and volcanic activity that encircles a large portion of the Pacific Ocean. The Ring of Fire affects California through the San Andreas Fault and comes around to Japan on the other side of the ocean.
Tectonic plates are pieces of the Earth’s crust, floating on the mantle, which is comprised of molten rock. Wherever these plates meet or separate, there is what’s called “tectonic activity.” These plate boundaries create earthquakes, volcanoes, and hot spots for all sorts of geological activity. The Ring of Fire is the most active region on the Earth in terms of tectonic and volcanic activity, which is why those areas (California, Japan, etc.) are particularly prone to earthquakes of volcanism.