Figure 2.
Results of three hydraulic-fracturing tests in Ävrö granodiorite at mine scale. HF1 (a) and HF2 (b) are conventional fracturing- and re-fracturing tests, respectively, with continuous water injection. HF3 (c) is a fatigue test with cyclic, progressive fluid injection before the occurrence of breakdown pressure. Left ordinate indicates flow rate (blue) and fluid pressure (green). Right ordinate shows cumulative number of AEs (black curve) and their magnitudes (red dots) over time (s) in the stimulation.