Early in the 18th century, Mentolat erupted and formed lava flows on its western flank. These are Mentolat's best preserved volcanic deposits. The eruption deposited lapilli pumice. No historical records of activity exist, however, although reports by Serrano in the 18th century may refer to a lava flow from Mentolat. The most recent eruption may have been in 1850, or 1710 ± 5.