The Australian Geological Survey Organisation (AGSO) (formerly the Bureau of Mineral Resources, Geology and Geophysics (BMR)) conducted a deep reflection seismicprofiling survey in the onshore portion of the Otway Basin in the southeastern part of South Australia and southwestern part of Victoria, from February to June 1992. The seismic surveyformed part of a National Geoscience Mapping Accord (NGMA) project to study the early development of the Otway Basin.
The objective of the seismic survey was to acquire new deep reflection seismic data (20 seconds two way travel time) using explosive seismic energy sources to improve on the knowledge of early sedimentary sequences in the Otway Basin, especially at depths greaterthan 3 km (ie. deeper than 2 seconds on a seismic section). Explosive seismic energy sources were used in an attempt to provide a stronger seismic energy source than the seismic vibratorsources currently used in the region by seismic contractors. Eight seismic lines with a total survey line length of 474 km were planned for the seismic survey, specifically positioned totarget the survey objectives. Positioning of the seismic lines was achieved through consultation with NGMA partners, industry and universities.
The seismic survey obtained 461 km of 5 to 10 fold CMP deep reflection seismic dataalong seven of the proposed seismic lines over a 15 week acquisition period. Line 8 was deleted from the program due to Line 2 being extended in length and budgetary constraints.In addition to the seismic survey, gravity observations were made by the Geological Survey of Victoria and AGSO at 300 m intervals along all seismic lines. All seismic lines were alsoflown by the AGSO geophysical aircraft to record aeromagnetic and radiometric data at a flight height of 100 m AGL.
