Ticsho was emplaced 4,050 years ago, Mauras and Yana Mauras 2,900 years ago while the eruption of Chilcayoc Grande occurred 1451 - 1523. The youngest eruptions occurred along the Jenchana-Ninanmama fault and the most recent event was dated to 370 years ago and took place at Chilcayoc Chico. A more recent eruption was reported in 1913, but it is not clear that it actually occurred in the Andagua volcanic field. Neither historical records nor local records such as legends mention volcanic activity although pre-Inka agricultural areas were impacted by lava flows and two towns were destroyed by volcanic activity later than the Spanish conquest. Presently, hydrogen sulfide emanates from the Ninamama flow and has generated gypsum and sulfur deposits, and fumarolic activity was reported in 2003 although other sources state that no fumarolic activity occurs; future eruptions are certainly possible.