The Pacific Rim is home to half the world's active volcanoes and 90 per cent of its earthquakes, yet nearly 800 million people live at its violent edge. This episode focuses on the Asia-Pacific side of the Pacific Ring of Fire, a living testament to the beauty and danger that geologic forces can deliver. Our journey begins in New Zealand where we find a 500-kilometre long slip-strike fault deep under the Pacific Ocean. And in Japan we scale the iconic peak of Mount Fuji and discover new ways to monitor, and hopefully one day predict, seismic activity.