Contrasting hydrological and mechanical properties of clayey and silty muds cored from the shallow Nankai Trough accretionary prism

Takahashi, Miki; Azuma, Shuhei; Uehara, Shin–ichi; Kanagawa, Kyuichi; Inoue, Atsuyuki

doi:10.1016/j.tecto.2013.01.008

Cited by 14 publications

(32 citation statements)

References 32 publications

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“…The observed weakness of the clay to silty clay sediments suggests that the frictional strength of faults is controlled mainly by the content of clay minerals, as has been demonstrated in many experimental studies (e.g., Summers and Byerlee 1977;Morrow et al 1992Morrow et al , 2000Brown et al 2003;Kopf and Brown 2003;Moore and Lockner 2004;Ikari et al 2009a,b;Tembe et al 2010;Saito et al 2013;Takahashi et al 2013). In contrast, the steady-state μ values of the silicic to calcareous ooze sediments from Unit II are high, measuring~0.8 and are comparable to the values reported for crustal rock samples (Byerlee 1978).…”

Section: Discussionsupporting

confidence: 75%

“…An increasing number of experimental studies have found that the frictional properties of subduction-zone material vary depending on mineralogy, such as clay content, emphasizing the expected strong material control on frictional properties along seismogenic subduction zone thrusts (Vrolijk 1990;Brown et al 2003;Kopf and Brown 2003;Ikari et al 2009a; Ujiie and Tsutsumi 2010;Tsutsumi et al 2011;Ikari et al 2013;Saito et al 2013;Takahashi et al 2013;Ujiie et al 2013). Given the diversity in subduction-zone stratigraphy (Underwood 2007), it is essential to characterize the material inputs to subduction zones with respect to their intrinsic frictional properties if fault behavior within seismogenic subduction zones is to be better understood (Vrolijk 1990;Underwood 2007).…”

Section: Introductionmentioning

confidence: 99%

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Frictional properties of sediments entering the Costa Rica subduction zone offshore the Osa Peninsula: implications for fault slip in shallow subduction zones

et al. 2014

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We examined the frictional properties of sediments on the Cocos plate offshore the Osa Peninsula, Costa Rica, and explored variations in the intrinsic frictional properties of the sediment inputs to the Costa Rica subduction zone. Sediment samples were collected at Site U1381A during the Integrated Ocean Drilling Program Expedition 334, and include hemipelagic clay to silty clay material (Unit I) and pelagic silicic to calcareous ooze (Unit II). The frictional properties of the samples were tested at a normal stress of 5 MPa under water-saturated conditions and with slip velocities ranging from 0.0028 to 2.8 mm/s for up to 340 mm of displacement. The experimental results reveal that the steady-state friction coefficient values of clay to silty clay samples are as low as~0.2, whereas those of silicic to calcareous ooze samples are as high as 0.6 to 0.8. The clay to silty clay samples show a positive dependence of friction on velocity for all tested slip velocities. In contrast, the silicic to calcareous ooze samples show a negative dependence of friction on velocity at velocities of 0.0028 to 0.28 mm/s and either neutral or positive dependence at velocities higher than 0.28 mm/s. Given the low frictional coefficient values observed for the clay to silty clay samples of Unit I, the décollement at the Costa Rica Seismogenesis Project transect offshore the Osa Peninsula likely initiates in Unit I and is initially very weak. In addition, the velocity-strengthening behavior of the clay to silty clay suggests that faults in the very shallow portion of the Costa Rica subduction zone are stable and thus behave as creeping segments. In contrast, the velocity-weakening behavior of the silicic to calcareous ooze favors unstable slip along faults. The shallow seismicity occurred at a depth as shallow as~9 km along the Costa Rica margin offshore the Osa Peninsula (M w 6.4, June 2002), indicating that materials characterized by velocity-weakening behavior constitute the fault zone at the depth of the seismicity. Fault slip nucleating along a fault in Unit II would be a likely candidate for the source of the shallow earthquake event.

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Section: Discussionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Frictional properties of sediments entering the Costa Rica subduction zone offshore the Osa Peninsula: implications for fault slip in shallow subduction zones

et al. 2014

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“…However, frictional properties of minor lithologies should also be investigated in order to fully evaluate the frictional properties of accretionary sediments. Here, we report the results of triaxial friction experiments on sandstone, tuff, and siltstone samples cored from the shallow Nankai Trough accretionary prism, in addition to experiments performed on claystone and siltstone samples already reported by Takahashi et al (2013). Their frictional properties are found to change systematically according to their content of clay minerals, in particular of smectite.…”

Section: Introductionmentioning

confidence: 81%

“…The unconformity boundary between the Miocene accretionary sediments and the overlying Pliocene-Pleistocene Kumano Basin sediments occurs at ≈ 922 mbsf (meters below the seafloor) in Hole B at Site C0002 and at ≈ 1,285 mbsf in Hole A at Site C0009 (Figures 1b and 2 Takahashi et al (2013), and samples C2571, C9073, and C9087 were additionally tested in this study. …”

Section: Location and In Situ Conditions Of Samples Testedmentioning

confidence: 99%

“…NanTroSEIZE IODP Expeditions 315, 316, 319, and 338 also revealed that the shallow (≤2,000 m below the seafloor) Nankai Trough accretionary prism is largely composed of claystone with subordinate siltstone, sandstone, and tuff Expedition 319 Scientists 2010;Strasser et al 2014). In order to evaluate the frictional properties of accretionary sediments in the Nankai Trough, friction experiments have therefore been conducted exclusively on cored mudstone (siltstone and claystone) samples (Hirose et al 2008;Ikari et al 2009Ikari et al , 2013Ujiie and Tsutsumi 2010;Ikari and Saffer 2011;Tsutsumi et al 2011;Takahashi et al 2013). However, frictional properties of minor lithologies should also be investigated in order to fully evaluate the frictional properties of accretionary sediments.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2014

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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 (V axial ) changed stepwise among 0.1, 1, and 10 μm/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 (μ ss ) at V axial = 1 μm/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 (Δμ ss /ΔlnV sliding ) 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.

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Deciphering the Late Cretaceous‐Cenozoic Structural Evolution of the North Peruvian Forearc System

et al. 2018

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The link between plate tectonics and the evolution of active margins is still an ongoing task to challenge since the acceptance of plate tectonic paradigm. This paper aims at deciphering the structural architecture and uplift history of the North Peruvian forearc system to better understand the evolution and the mechanics that govern the Late Cretaceous‐Cenozoic building of this active margin. In this study, we report surface structural geology data, interpretation of seismic reflection profiles, apatite fission track data, and the construction of two offshore‐onshore crustal‐scale balanced cross sections. The structure of the North Peruvian forearc system is dominated by an accretionary style with northwestward propagation of thrust‐related structural highs involving continental/oceanic basement rocks and off‐scrapped sediments. The thrust systems bound thick thrust‐top forearc depocenters mainly deformed by crustal normal to strike‐slip faults and thin‐skinned gravitational instabilities. The sequential restoration of the margin calibrated with apatite fission track data suggests a correlation between uplift, shortening, and plate convergence velocity during Late Cretaceous and Miocene. Pliocene‐Quaternary shortening and uplift of the coastal zone is rather related to the subduction of asperities during convergence rate decrease. The development of crustal normal to strike‐slip faulting and subsidence zones might be the consequence of slab flexure, local basal erosion along subduction fault, and/or oblique subduction associated with sediment loading control. We conclude that the evolution of the North Peruvian forearc system was controlled by subduction dynamics, strong sediment accumulation, and recent ridge subduction, and it recorded the orogenic loading evolution of the Andes over the Cenozoic.

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Contrasting hydrological and mechanical properties of clayey and silty muds cored from the shallow Nankai Trough accretionary prism

Cited by 14 publications

References 32 publications

Frictional properties of sediments entering the Costa Rica subduction zone offshore the Osa Peninsula: implications for fault slip in shallow subduction zones

Frictional properties of sediments entering the Costa Rica subduction zone offshore the Osa Peninsula: implications for fault slip in shallow subduction zones

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

Deciphering the Late Cretaceous‐Cenozoic Structural Evolution of the North Peruvian Forearc System

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