Fragmented cinder and spatter material and lava flows dip at angles as high as 55° away from the central vent on the eastern and southern side of Vulcan.

A solidified lava pond that consists of a massive gray basalt with weakly developed columnar jointing occupies the crater of Vulcan.

Radial, sinuous lava tubes 8 to 20 inches (200 to 510 mm) across and 300 feet (91 m) long are preserved on the northeast and northwest flanks of Vulcan.

Vulcan lies in Petroglyph National Monument, with access to the volcanoes during business hours, after which any vehicles are locked in and subject to fines and impound.

[4] From 1951 to 1973, a large letter J representing the College of St. Joseph on the Rio Grande (later renamed the University of Albuquerque) was painted on the eastern slope of the volcano.