Lascar has erupted about thirty times since the 19th century. Written reports of volcanic activity exist since the 16th century, when the Spaniards arrived in the region, though few records exist from before 1848. Volcanic activity recorded after 1848 consists chiefly of fumarolic emissions and occasional explosive activity. Recorded eruptions occurred in 1858, 1875, 1883-1885, 1898-1900(?) and 1902, ranging from a volcanic explosivity index (VEI) of 0 to VEI 2. The 1933 eruption was seen as far away as Chuquicamata. Another series of eruptions occurred between November 1951 and January 1952; one eruption is recorded from 1940. Eruptions were observed in March 1960, which were accompanied by earthquakes felt in Toconao, as well as in September 1964 when ash fell in Socaire. Yet another eruption sequence occurred between 1959 and 1969. Eruptions in 1972 and 1974 are uncertain. For some eruptions, including the January 1854 eruption, it is not clear whether they occurred at Lascar or Aguas Calientes, and some early reports of volcanic activity at Aguas Calientes probably refer to Lascar.