These are the Emerald Lakes of New Zealand, located in Tongariro National Park. These pits are the consequences of the volcanic activity which led to the formation of the National Park
These lakes sit in volcanic craters on the slopes of the volcano Mount Tongariro. They were formed by explosions caused when upwelling magma in the volcano intersected water in the ground, boiling it to steam and causing it to explode. The colors created from minerals and elements that are leached out of the rocks as water flows through.
Tongariro National Park is the oldest national park in New Zealand. It became a national park in 1933 and is also a UNESCO world heritage site. It was actually the first World Heritage site declared under new rules which were designed to protect areas of cultural significance. The park hosts 3 volcanoes including Tongariro which are considered significant to the native Maori people.
The volcanoes are driven by subduction, part of the tectonic forces that give rise to New Zealand. Part of the Pacific Plate is being pushed beneath the Indo-Australian plate, which releases fluids into the mantle and drives the formation of magma.
Image credit: http://pixabay.com/en/new-zealand-tongariro-crossing-83645/