David Sunwall

Latest advances in over‐sea‐ice seismic reflection surveys: offshore New Harbor, Antarctica

Approximately 48 km of multi-channel seismic reflection data were collected during the austral spring of 2008 on a sea-ice platform east of New Harbor, Antarctica. The Offshore New Harbor (ONH) survey is the latest in a series of three successful over-sea-ice seismic reflection surveys conducted in McMurdo Sound, Antarctica (Figure 1). Previous to the 2008 ONH survey were the 2005 Southern McMurdo Sound (SMS) and 2007 Mackay Sea Valley (MSV) surveys. Upgrades in the ONH project’s field equipment substantially increased the rate at which seismic data could be acquired in a sea-ice environment compared to all previous surveys. Moreover, despite the success of the SMS survey, timing errors were irreversibly left in SMS data, and static errors were unknowingly left within the SMS data. For all three surveys, timing errors were caused by miscommunications between the Generator Injector (GI) air gun (seismic source) and the acquisition software. Static errors—only on seismic traces coincident with source locations—were caused by GI air gun created air bubbles that were trapped beneath the sea ice. For MSV and ONH data, two methods of statics corrections greatly increased the quality of the final stacked seismic sections and mitigated the aforementioned timing and static errors.