Why are the Jemez Mountains volcanic?
The Jemez Mountains exist at the boundary of two rifts in the earth – the Rio Grande Rift (running from Leadville, CO to Northern Mexico), and the relatively weaker Jemez Lineament (running from southeast Arizona to Colorado). Since these rifts are weak spots in the earth, underground magma (molten rock) flows toward the earth’s surface at these points, and particularly at the intersection of these rifts (Martin).
