Table 3 Orientation of principal stresses and stress ratio in the active cluster area. Azimuth is measured clockwise from the north in degrees. Dip is measured downward from the horizontal surface in degrees. Stress ratio is defined by R = (σ1 − σ2)/(σ1 − σ3). The values in the brackets indicate the range of uncertainty.
From: Focal mechanisms and stress field in the Atotsugawa fault area, central Honshu, Japan
Depth [km] | Maximum principal stress σ1 | Intermediate principal stress σ2 | Minimum principal stress σ3 | R | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Azimuth | Dip | Azimuth | Dip | Azimuth | Dip | |||||||||
0−8 | 108 | [+93, +124] | 4 | [−15, +25] | −137 | [−316, +43] | 80 | [−9, +90] | 17 | [−141, +60] | 9 | [−77, +89] | 0.78 | [0.4, 1.0] |
8−20 | 107 | [−23, +164] | 10 | [−73, +82] | −15 | [−77, −15] | 72 | [−10, +84] | −160 | [−172, −152] | 15 | [+3, +26] | 0.05 | [0.0, 0.4] |