The Blue Jewel of Waimangu
Inferno Crater Lake:
From the Waimangu Wanderer's Guide:
This steaming and usually pale blue jewel of Waimangu lies in a crater blown from the side of Mount Haszard in the 1886 eruption. Lake level follows complicated rhythmic cycles with shallow recessions occurring every few days and/or deeper recessions at longer intervals. The top of the white silica deposit marks overflow level. Its most common behavior is to overflow for two or three days, recede about 8m during some 15 days, partly refill over three to four weeks, oscillate for a while, and then start to overflow again. The lake is roughly trumpet shaped. Its depth when full is 30 m. Overflow temperatures can reach 80°C (176°F). The the water is highly acidic with a pH sometimes of 2.1. Inferno Crater Lake is the largest geyser-like feature in the world, although the geyser cannot be seen since it plays at the bottom of the lake. It has a unique relationship with Frying Pan lake. When Inferno crater lake is overflowing there's a decrease in the discharge for Frying Pan Lake and when Inferno Crater Lake is receding the discharge from frying pan lake is greater than usual.