Improving the Resolution of Deep-Crustal Seismic Data to Study Shallow Gas Hydrates on the Hikurangi Margin, New Zealand

Abstract

Methane gas hydrate, an ice-like form of water and methane, is abundant on continental margins worldwide and may constitute a future energy source. The Hikurangi margin offshore of New Zealand is predicted to contain vast quantities of gas hydrate. Much of our knowledge on Hikurangi margin gas hydrates stems from crustal seismic data which are of limited use for gas hydrate reconnaissance because of relatively low resolution. We here present results from reprocessing of a crustal seismic line with a focus on maximising resolution. We benchmarked our results to a higher-resolution survey that was recently acquired along this line. While the reprocessed crustal data are not ideal for gas hydrate investigations, we are able to identify most major features relevant to gas hydrate occurrence, in particular bottom simulating reflections, free gas close to the seafloor, and normal faults that intersect the seafloor. Our results demonstrate that reprocessing of crustal seismic data for maximum resolution may lead to significant improvements for studying gas hydrates.