Breaking Crust: Sonar finds new kind of deep-sea volcano

Explorations east of Japan have revealed a previously unknown type of volcano.

Volcanoes typically emerge in one of three geological settings, explains Stephanie P. Ingle, a geochemist at the University of Hawaii in Honolulu. Some crop up along mid-ocean ridges, where Earth’s tectonic plates spread apart. Others, such as those on land along the western coast of North America, form where one plate is being subducted, or forced beneath, another plate.