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doi:10.14379/iodp.sp.375.2017

Cited by 12 publications

(19 citation statements)

References 37 publications

(51 reference statements)

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“…The integrated log-core-seismic data will be used to identify borehole depth targets at the upper plate and frontal thrust sites for the installation of CORK observatories during Expedition 375 in 2018 (for further details, see Saffer et al, 2017). These observatories will span across the entire SSE source region and be used to monitor deformation, temperature, and fluid flow related to SSE cycles.…”

Section: Slow Slip Eventsmentioning

confidence: 99%

“…After LWD, coring during Expedition 375 will provide samples and data sets for sediment and rock physical properties, mineral composition, pore fluid composition, and downhole temperature, with a focus on hydrogeology and fault mechanical processes. In addition to Site U1520 in the Hikurangi Trough, Expedition 375 will also drill and core a second inputs site (proposed Site HSM-08A; see Saffer et al [2017]) to target the upper (<200 m) altered basaltic basement of the Tūranganui Knoll Seamount massif ( Figure F10). The LWD and core data from all inputs sites are also critical for refined depth conversion of the existing 2-D seismic data and 3-D seismic data collected by the Marcus Langseth shortly after Expedition 372.…”

Section: Hikurangi Subduction Margin: Hypotheses and Scientific Objecmentioning

confidence: 99%

“…the SSE source region. For Objective 3: installation of borehole observatories spanning the SSE source region, refer to Saffer et al (2017).…”

Section: Hsm Objective 3: Installation Of Borehole Observatories Spanmentioning

confidence: 99%

“…These attributes made the northern Hikurangi margin amenable to an ambitious scientific drilling program involving LWD, coring, and installation of borehole observatories. To achieve this program, IODP scheduled this work across two expeditions on the JOIDES Resolution (Expeditions 372 and 375; Saffer et al, 2017). Drilling during Expedition 372 represented the first IODP scientific drilling ever targeted at SSE phenomena.…”

Section: Hikurangi Subduction Slow Slipmentioning

confidence: 99%

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2018

International Ocean Discovery Program Preliminary Report

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International Ocean Discovery Program (IODP) Expedition 372 combined two research topics, slow slip events (SSEs) on subduction faults (IODP Proposal 781A-Full) and actively deforming gas hydrate-bearing landslides (IODP Proposal 841-APL). Our study area on the Hikurangi margin, east of the coast of New Zealand, provided unique locations for addressing both research topics. SSEs at subduction zones are an enigmatic form of creeping fault behavior. They typically occur on subduction zones at depths beyond the capabilities of ocean floor drilling. However, at the northern Hikurangi subduction margin they are among the bestdocumented and shallowest on Earth. Here, SSEs may extend close to the trench, where clastic and pelagic sediments about 1.0-1.5 km thick overlie the subducting, seamount-studded Hikurangi Plateau. Geodetic data show that these SSEs recur about every 2 years and are associated with measurable seafloor displacement. The northern Hikurangi subduction margin thus provides an excellent setting to use IODP capabilities to discern the mechanisms behind slow slip fault behavior. Expedition 372 acquired logging-while-drilling (LWD) data at three subduction-focused sites to depths of 600, 650, and 750 meters below seafloor (mbsf), respectively. These include two sites (U1518 and U1519) above the plate interface fault that experiences SSEs and one site (U1520) in the subducting "inputs" sequence in the Hikurangi Trough, 15 km east of the plate boundary. Overall, we acquired excellent logging data and reached our target depths at two of these sites. Drilling and logging at Site U1520 did not reach the planned depth due to operational time constraints. These logging data will be augmented by coring and borehole observatories planned for IODP Expedition 375. Gas hydrates have long been suspected of being involved in seafloor failure; not much evidence, however, has been found to date for gas hydrate-related submarine landslides. Solid, ice-like gas hydrate in sediment pores is generally thought to increase seafloor strength, as confirmed by a number of laboratory measurements. Dissociation of gas hydrate to water and overpressured gas, on the other hand, may weaken and destabilize sediments, potentially causing submarine landslides. The Tuaheni Landslide Complex (TLC) on the Hikurangi margin shows evidence for active, creeping deformation. Intriguingly, the landward edge of creeping coincides with the pinch-out of the base of gas hydrate stability on the seafloor. We therefore hypothesized that gas hydrate may be linked to creep-like deformation and presented several hypotheses that may link gas hydrates to slow deformation. Alternatively, creeping may not be related to gas hydrates but instead be caused by repeated pressure pulses or linked to earthquake-related liquefaction. Expedition 372 comprised a coring and LWD program to test our landslide hypotheses. Due to weather-related downtime, the gas hydrate-related program was reduced, and we focused on a set of experiments at Site U1517 in the creeping part o...

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Section: Slow Slip Eventsmentioning

confidence: 99%

Section: Hikurangi Subduction Margin: Hypotheses and Scientific Objecmentioning

confidence: 99%

“…the SSE source region. For Objective 3: installation of borehole observatories spanning the SSE source region, refer to Saffer et al (2017).…”

Section: Hsm Objective 3: Installation Of Borehole Observatories Spanmentioning

confidence: 99%

Section: Hikurangi Subduction Slow Slipmentioning

confidence: 99%

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2018

International Ocean Discovery Program Preliminary Report

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“…Quantitative XRD becomes more important when an expedition's science plan includes extensive whole-round sampling of cores for shore-based measurements of frictional, geotechnical, and hydrogeological properties; this emphasis is added because many such properties are modulated by bulk sediment composition. The science plans for International Ocean Discovery Program (IODP) Expeditions 372 and 375, which drilled in the Hikurangi subduction zone offshore New Zealand, fell into the second category (Barnes et al, 2017;Saffer et al, 2017). Accordingly, considerable effort was invested to generate reasonably accurate mineral abundance values using XRD data.…”

Section: Introductionmentioning

confidence: 99%

Data report: standard mineral mixtures, normalization factors, and determination of error for quantitative X-ray diffraction analyses of bulk powders and clay-sized mineral assemblages

Underwood¹,

Lawler²,

McNamara³

2020

Hikurangi Subduction Margin Coring, Logging, and Observatories

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Fluid Accumulation, Migration and Anaerobic Oxidation of Methane Along a Major Splay Fault at the Hikurangi Subduction Margin (New Zealand): A Magnetic Approach

2021

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The production, presence and migration of fluids in fore-arc regions are fundamental to the distribution and advection of heat (Fagereng & Ellis, 2009). Mineral diagenesis, the formation and dissipation of methane hydrate and metamorphism at depth control the geochemistry of pore-fluids (Kastner et al., 2014; D. M. Saffer & Screaton, 2003; Torres et al., 2004). Pore-fluid pressure counteracts hydrostatic stress, and thus is thought to weaken the frictional stability of the sediments and the mechanical strength of fault zones (

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Untitled

Cited by 12 publications

References 37 publications

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Untitled

Data report: standard mineral mixtures, normalization factors, and determination of error for quantitative X-ray diffraction analyses of bulk powders and clay-sized mineral assemblages

Fluid Accumulation, Migration and Anaerobic Oxidation of Methane Along a Major Splay Fault at the Hikurangi Subduction Margin (New Zealand): A Magnetic Approach

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