The volcano has a number of adventive vents on its slopes, especially the northwestern and southeastern slope. These include Ch'aska Urqu on the southeastern slope and La Celosa (; also known as El Ingenio) on the northwestern. They lie at distances of and from the summit vent, respectively. The alignment of these subsidiary vents with the summit vents suggests that a N55°W striking lineament influenced their eruption; such channelling of magma along radial fractures has also been observed on other volcanoes such as Medicine Lake volcano, Mount Mazama and South Sister. A normal fault runs across the main edifice but is not aligned with these adventive vents, and the Pastos Grandes-Lipez-Coranzuli lineament intersects with the volcanic arc at Ollagüe. Fault scarps are found on the northwestern and southeastern side of the edifice. Overall, northwest trending lineaments exercised a strong influence on the tectonic development of Ollagüe, and may be the path that feeder dykes of the more recent eruptions followed. The basement undergoes extension perpendicularly to the lineament.