Frictional properties of the shallow Nankai Trough accretionary sediments dependent on the content of clay minerals

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doi: 10.1186/1880-5981-66-75
Author(s): Takahashi, Miki; Azuma, Shuhei; Ito, Hidenori; Kanagawa, Kyuichi; Inoue, Atsuyuki
Author Affiliation(s): Primary:
Japanese Geological Survey, Institute of Earthquake and Volcano Geology, Tsukuba, Japan
Other:
Chiba University, Japan
Volume Title: Earth, Planets and Space
Source: Earth, Planets and Space, 66(1). Publisher: Terra Scientific Publishing Company (TERRAPUB), Tokyo, Japan. ISSN: 1343-8832
Note: In English. 47 refs.; illus., incl. sect., 3 tables, sketch map
Summary: We conducted triaxial friction experiments on the shallow Nankai Trough accretionary sediments at confining pressures, pore water pressures, temperatures close to their in situ conditions, and axial displacement rates (Vaxial) changed stepwise among 0.1, 1, and 10µm/s. The results revealed that their frictional properties change systematically according to the content of clay minerals, smectite in particular. The steady-state friction coefficient (µss) at Vaxial = 1µm/s decreases with increasing clay mineral content, shown in weight percent, from 0.82 for a sandstone sample (6 wt%), through 0.71 for a tuff sample (∼17 wt%), and 0.53 to 0.56 for siltstone samples (29 to 34 wt%), to 0.25 for a claystone sample (42 wt%). Slip-dependent frictional behavior changes accordingly from slip hardening for the sandstone sample, through quasi steady-state slip for the tuff and siltstone samples, to distinct slip weakening for the claystone sample. Although all samples exhibit velocity-strengthening behavior upon stepwise changes in sliding velocity, the ratio of the (a - b) value to the velocity dependence of steady-state friction (∆µss/∆lnVsliding) decreases with increasing clay mineral content, which implies that the friction component decreases while the flow component increases accordingly. Thus, faulting in the shallow Nankai Trough accretionary prism is likely controlled by the clay mineral content, in particular the smectite content, in the sediments as well as in the fault zones. Copyright 2014 The Author(s) and Takahashi et al.; licensee Springer.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 30 Engineering Geology; Accretionary wedges; Clastic rocks; Clay minerals; Claystone; Confining pressure; Decollement; Expedition 319; Experimental studies; Faults; Friction; IODP Site C0002; IODP Site C0009; Igneous rocks; Integrated Ocean Drilling Program; Kumano Basin; Marine sediments; Mechanical properties; NanTroSEIZE; Nankai Trough; North Pacific; Northwest Pacific; Pacific Ocean; Pore pressure; Pyroclastics; Rock mechanics; Sandstone; Sedimentary rocks; Sediments; Sheet silicates; Silicates; Siltstone; Smectite; Steady-state processes; Temperature; Triaxial tests; Tuff; Volcanic rocks; West Pacific
Coordinates: N331800 N331801 E1363801 E1363800
N332728 N332728 E1363209 E1363209
Record ID: 2017026340
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by Springer Verlag, Berlin, Federal Republic of Germany