 The growth of a lava dome over the last 600 years was accompanied by phreatic activity.Tephrochronology suggests the occurrence of eruptions 1,350, 750 AD, 550 ± 100 BC, 1,850 BC, 3,050 BC, 5,550 BC, 7,050 BC and 7,550 BC.Nemo Peak is a dormant volcano.