Volcán San José volcano on the Chile-Argentina lies at the southern end of a volcano group that includes the older volcanoes of Marmolejo and Espíritu Santo. San José volcano has a broad 2 km x 0.5 km summit region with overlapping and nested craters, pyroclastic cones, and blocky lava flows.
Historic activity recorded since 1822 consisted in mild phreatomagmatic ash eruptions.
The glaciated 6109-m-high Marmolejo stratovolcano is truncated by a 4-km-wide caldera, breached to the NW, that has been the source of a massive debris avalanche. Volcán la Engorda and Volcán Plantat, located SW of Marmolejo and NW of San Jose, have also been active during the Holocene.
An 8-km-long lava flow traveled to the SW from the 1-km-wide summit crater of Espíritu Santo volcano, which overlaps the southern slope of Marmolejo.
