| Comments: | Overnight or early morning. From "Hot spring activity in the geyser basins of the Firehole River for the 1967 season," pg. 15: "During 1967 but one eruption occurred to date. This activity was on May 4. The above eruption began sometime during the night or early morning hours of the 4th. This eruption lasted for not less than 36 hours. It was the water-phase type with recurring surges of activity taking place about every 25 to 30 minutes. The active periods lasted from 3 to 5 minutes...During the past season Vault Geyser has been very active, the eruptions during most days taking place almost hourly...An eruption of Giantess drains all the water from Vault. It takes 2 to 3 days for Vault to refill following an eruption of Giantess." |