Skip to main content
Earth, Planets and Space

Table 1 Key parameters at the depths of breakout occurrence in Hole C0002A within the overlapping interval for the two holes

From: In situ stress magnitude and rock strength in the Nankai accretionary complex: a novel approach using paired constraints from downhole data in two wells

Depth (mbsf)

S hmin (MPa)

S v (MPa)

P p (MPa)

Breakout width (°) C0002A

APRS C0002A (MPa)

APRS C0002F (MPa)

V p (m/s)

S Hmax (MPa)

UCS (MPa)

900

13.0

16.4

9.1

32

9.5

12.2

2380

17.0 ± 5.2

12.8 ± 7.2

950

13.8

17.3

9.6

6

10.2

13.1

2344

17.2 ± 5.1

12.2 ± 7.8

1000

14.8

18.2

10.1

7

10.7

13.8

2357

18.6 ± 5.1

9.3 ± 5.3

1150

17.6

20.9

11.5

110

13.0

15.3

2422

20.1 ± 3.2

6.4 ± 2.6

1300

20.4

23.9

13.1

78

14.6

17.2

2805

23.8 ± 4.7

10.2 ± 4.8

1386

22.0

25.4

13.9

100

16.5

18.3

3000

23.7 ± 2.9

5.6 ± 2.4

  1. S hmin is determined from a gradient defined by the leak-off tests. Vertical stress (S v), formation pore pressure (P p), breakout width, annual pressure (APRS), and P-wave velocity (V p) are measured, estimated, or calculated from drilling data (Tobin et al. 2015; Strasser et al. 2014). Maximum horizontal stress (S Hmax) and unconfined compressive strength (UCS) are constrained by our forward modeling analyses. All stresses and pressures are referenced to zero at the seafloor. The best-fit S Hmax and UCS values in are taken from the lowest residual values
Back to article page