Hidden water over 220 °C: how do you find it?

Below some hot springs and steaming ground, water hotter than 220 °C fills the rock, and nobody can see it. Here is how geoscientists read it anyway, like a doctor: from the waters, the rocks and the physics, joined in one conceptual model. 0:00 The question 0:19 Like a doctor's diagnosis 0:34 Key terms 1:07 The waters 1:55 The rocks 2:35 The physics 3:13 Where to drill: a worked example 3:52 Recap 4:20 Your turn #geothermal #geology #earthscience