It's not always obvious what it is that scientists find beautiful about a graph, microscope slide, soil sample or some other aspect of their work. It just looks like numbers, blobs or dirt to the rest of us. But sometimes a scientific result or product is so visually appealing, anyone would want to hang it on their wall as art.

Geological maps are often in this category. And some of the most beautiful geological maps are of volcanoes. The colors on geological maps represent different rock units of different ages. With an active lifespan of thousands, or even hundreds of thousands of years, volcanoes produce many layers of ash and flows of lava that will end up as different colors on the map. And with the circular shape of many volcanoes and the radiating rock units, the maps can really be striking.

Here we've collected some excellent examples of geological maps of volcanoes from the United States and Japan. You don't have to be a geologist or even a scientist to have trouble picking a favorite.

Special thanks to the Geological Survey of Japan for permission to use some of their maps in this gallery.

Above:

Type: stratovolcano
Last eruption: 2010
Summit elevation: 2,674 ft. (815 m.)

Miyake-jima rises around 3,600 feet from the sea floor around 110 miles southwest of Tokyo. The top of the volcano is a 5-mile-wide circular island that is home to around 3,000 people. It has erupted as recently as last year, but its last big eruption sequence occurred in June-July and September 2000 (see below). It was accompanied by thousands of earthquakes including a magnitude 6.4 that killed one person, 9-mile high ash plumes, pyroclastic flows, ashfalls, crater collapses and an evacuation order that lasted five years and kept the island largely uninhabited until January 2011.

Geological Map: Geological Survey of Japan. Image below: Miyake-jima in July 2000 (left) after large eruptions and venting steam in September 2000 (right) (Ash appears dark gray, vegetation appears red, and water is blue-gray). NASA.