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This dataset contains underlying data and results of 3D gas hydrate modelling at the southern Hikurangi Margin using PetroMod™ software and accompanies a manuscript published in the Geochemistry Geophysics Geosystems journal (DOI10.1029/2019GC008275). The model integrates thermal and microbial gas generation, migration and hydrate formation. Modelling these processes has improved the understanding of factors controlling hydrate distribution. Three spatial trends of concentrated hydrate occurrence are predicted. The first trend (I) is aligned with the principal deformation front in the overriding Australian plate. Concentrated hydrate deposits are predicted at or near the apexes of anticlines and to be mainly sourced from focussed migration and recycling of microbial gas generated beneath the hydrate stability zone. A second predicted trend (II) is related to deformation in the subducting Pacific plate associated with former Mesozoic subduction beneath Gondwana and the modern Pacific-Australian plate boundary. This trend is enhanced by increased advection of thermogenic gas through permeable layers in the subducting plate and focussed migration into the Neogene basin fill above Cretaceous‒Paleogene structures. The third trend (III) follows the northern margin of the Hikurangi Channel and is related to the presence of buried strata of the Hikurangi Channel system.
This is the data collected by a major controlled-source and passive seismic imaging experiment, the Seismic Array HiKurangi Experiment (SAHKE). The SAHKE project was designed to investigate the physical parameters controlling locking at the plate boundary beneath the southern North Island and characterise slip processes in a major segment of the Hikurangi system. The components of data were acquired between November 2009 and April 2010 by GNS Science, Victoria University of Wellington, and Earthquake Research Institute (University of Tokyo, Japan) in conjunction with Ministry of Economic Development, Crown Minerals. 480 km of marine multichannel seismic data were acquired on 3 SAHKE profiles off the east and west coasts of the southern North Island and recorded by 36 short-period, 10 broadband and 20 ocean bottom seismometers along a single transect line. Additional offshore shot lines were recorded by 9 short-period seismometers in a north-south profile line, on the western margin, and 13 short-period seismometers on two profile lines on the eastern margin of the lower North Island. Additionally, 69000 offshore airgun sources were recorded by 48 short-period and two broadband seismometers distributed in a dispersed array during the recording of 2800 km of the Pegasus Basin survey. This same distributed array recorded local and teleseismic earthquakes over a 4 month period.
This is the offshore dataset of a large onshore-offshore seismic experiment on the Hikurangi margin of North Island, New Zealand, with a team of scientists from New Zealand, the United States, and Japan. This data acquisition was part of the SHIRE project (“Seismogenesis at Hikurangi Integrated Research Experiment”) and occurred in 2017. The goals of this Earth science project were: 1) to obtain constraints on the deep structure of the Hikurangi margin, with an emphasis on Raukumara peninsula in the north, and 2) to record seismicity over several months. During the marine seismic experiment, we used the acoustic source and streamer of the US academic research vessel R/V Marcus Langseth (voyage MGL1708) to gather marine seismic reflection and refraction data. The R/V Tangaroa took part in a voyage undertaking OBS operations in cooperation with this, deploying and recovering a fleet of 100 short-period ocean-bottom seismometers (OBSs) from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Voyage TAN1710’s deployed and recovered OBSs at 114 sites along four major lines. SHIRE Line 1 is oriented NW–SE between the Bay of Plenty and the northern Hikurangi Trough. Land seismometers on the Raukumara peninsula section of this transect recorded the Langseth source as well. SHIRE Line 2 is a margin-crossing transect on the southern Hikurangi margin, while Line 3 and Line 4 are two margin-parallel lines on the continental shelf and on the Hikurangi Plateau, respectively. After the R/V Marcus Langseth started surveying these geophysical transects, 21 of the instruments from Lines 1 and 3 were repositioned on SHIRE Line 4.