This submission provides processed seismic reflection data from Research Voyage TAN1808, which took place aboard RV Tangaroa between the 8th of September and the 5th of October, 2018. Raw data are lodged with the New Zealand Government (https://data.nzpam.govt.nz). The research voyage was aimed at characterizing gas hydrate systems on the southern Hikurangi margin of New Zealand, in the region offshore eastern New Zealand. Data were collected with NIWA's (New Zealand) multi-channel seismic reflection system and were processed using the Globe Claritas processing software. Full details of acquisition and processing are included in the voyage report (Crutchley et al. 2018: doi:10.21420/73WW-1W83) and other linked publications.

All SEG-Y files have the following important binary header word definitions, required for loading data:Start time: 2-byte integer: Bytes 105-106Trace Sample Count: 2-byte integer: Bytes 115-116Sample Interval (microseconds): 2-byte integer: Byte 117-118CDP Number: 4-byte integer: Bytes 5-8X location: 4-byte integer: Bytes 81-84 (Note: Coordinates are in metres of UTM Zone 60S, WGS84 Datum)Y location: 4-byte integer: Bytes 85-88 (Note: Coordinates are in metres of UTM Zone 60S, WGS84 Datum)Trace coordinates (ascii format file):The file All_trace_coordinates.txt contains the coordinates of all traces in the corresponding SEG-Y files. These are useful for plotting lines in GIS software, for example. Note: All coordinates are also in the binary headers of the SEG-Y data.The ascii file has the following four columns: