Publication Date:
2019
Description:
Abstract
The strength of accretionary prisms is important for understanding their formation and the generation of earthquakes along the underlying plate boundary faults. We establish a continuous depth profile of rock strength and possible ranges of the minimum and maximum horizontal stresses (Shmin and SHmax) based on indentation tests on cuttings samples at the Integrated Ocean Drilling Program Site C0002 in the Nankai accretionary prism. The rock strength (i.e., differential stress) increases with depth from 4.8 and 10.3 MPa at 975 meters below the seafloor (mbsf) to 21.4 and 55.9 MPa at 3005 mbsf in normal and reverse faulting regimes, respectively. The minimum value of Shmin and the maximum value of SHmax range from 32.9 and 48.0 MPa at 975 mbsf to 56.3 and 133.6 MPa at 3005 mbsf, respectively. Our estimated strength, in combination with Coulomb wedge model, may improve understanding of the evolution of accretionary prisms.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
