Level of fitness: hard - tramping on uneven and steep ground, carrying large backpack, passing through streams and glaciers, long hikes

 We will start our hike from the eastern ring plain, where tephra deposits document a detailed history of the past explosive activity of Mt Ruapehu and are sandwiched between debris avalanche and lahar deposits that further outline the hazards posed by this volcano. As we move to higher grounds along the Whangaehu valley, the tephras from explosive eruptions are replaced with lava flows that form the current summit and older flank-forming sequences, including those of the Wahianoa Formation (160-88 ka). The latter lava flows were emplaced adjacent to valley-filling glaciers and have produced steep ridges and bluffs, which provide excellent outcrops to study lava-ice interaction processes. Reaching the higher grounds, we will explore how hydrothermal alteration and deposits associated with the most recent eruptions over the last 100 years (e.g. 2007, 1995-96, 1988, 1975, 1945) have reshaped the modern landscape. These proximal areas represent the lithocap facies of an ancient hydrothermal system, formed during emplacement of Wahianoa Formation lavas, and also a currently active vent-type hydrothermal system, hosting the famous strongly acidic Crater Lake.

Please note that a good physical fitness is required, and expect tramping on uneven and steep ground and carrying large backpack. Mountaineering experience is a plus, but it is not a requirement to complete this field trip.