Jornada del Muerto Volcano is a small shield volcano and broad basaltic lava field in central New Mexico at the north end of the Jornada del Muerto basin. About 760,000 years ago, eruptions spread slow, rough ʻaʻā lava across more than 170 square miles, creating a hazardous malpaís landscape. Though the main vent rises only about 150 feet above the surrounding terrain, the volcanic field totals about 3 cubic miles of erupted material and includes nested spatter cones, lava pools, and a crater within the principal cone. One major flow reached the Rio Grande, forming part of its east bank and briefly damming the river.