Figure 4: Stress field rotation caused by volcanic activity.
From: Monitoring eruption activity using temporal stress changes at Mount Ontake volcano
(a) The regional stress pattern in the summit region. (b) Horizontal stress rotation. (c) Vertical stress rotation. The stress pattern is shown by the focal spheres (lower hemisphere projections) in which nodal planes are the maximum shear planes. The blue, light green and red arrows show the axes of the maximum (σ1,), intermediate (σ2) and minimum (σ3) compressive principal stresses, respectively. The pink dashed line in a indicates the strike of possible inflating cracks. The pink arrows mark the main direction of crack opening.
