Detailed Analyses of Seismic Anomalies Associated with Gas Hydrates in the Southern Hikurangi Margin, New Zealand

The Hikurangi Margin, east of the North Island of New Zealand, contains a significant gas hydrate province. However, the distribution, concentration and dynamics of hydrate accumulations in the southern portion of the margin (the Pegasus Sub-basin) off the northeastern coast of the South Island are poorly constrained due to a lack of data. In late 2009 and early 2010, a seismic dataset consisting of approximately 3000 km of long-offset 2D seismic data was collected in the Pegasus Sub-basin. Bottom-Simulating Reflections (BSRs) are widespread in the data, and they are supplemented by other features that may indicate the presence of free gas and gas hydrates in zones of high concentration. We present the results of reprocessing and analysis of the data that has focussed on the identification of such specific gas-related features.