Answer: The Pacific Ocean

Where the tectonic plates of the Earth meet you often find areas of intense geological activity, including earthquakes and volcanic activity. Among the multitude of plates that make up the surface of the Earth and the deep floors of the ocean, you’d be hard pressed to find an area more active than that bordering the large Pacific plate.

Almost the entire border of the Pacific plate, especially where it presses against the North American plate, Filipino plate, and the even by proxy the pressure it exerts on the South American plate through the smaller Nazca plate that sits between the two, you’ll find areas of volcanic activity. So much volcanic activity, in fact, that the entire U-shaped region sweeping all the way up from New Zealand, through Indonesia and the Philippines, through Japan, and then swinging around through the southern coast of Alaska and all the way down the west coast of North, Central, and South America right down to southern Chile, is the most volcanically active region on Earth and referred to as the “Ring of Fire”.

Over the last approximate 12,000 years, 20 of the 25 largest volcanic explosions have occurred along the plate boundaries of the Pacific plate and the adjoining plates. Volcanoes aren’t the only thing people living along the plate boundaries have to worry about either. Since 1900, around 90 percent of the world’s earthquakes and 81 percent of the world’s largest earthquakes have occurred along the Ring of Fire.