Seismic imaging beneath the Eucla Basin limestones

Abstract

Geoscience Australia in collaboration with the Geological Survey of Western Australia conducted a seismic testing program on the Eucla Basin carbonate sediments during May 2012, during a survey to collect deep seismic data across the western Eucla Basin. These data were collected as part of the Albany-Fraser Seismic Survey that consists of three traverses in south-east Western Australia with a total length of 671 km. The major aim of this survey was to image the basement relationship between the Yilgarn craton, the Albany-Fraser zone, and basement rocks further east. Much of this eastern area is covered by the limestones of the Eucla Basin, and there has been little seismic data acquired in this area. These tests were required to confirm the feasibility of collecting deep seismic data beneath the limestones through the region. Geoscience Australia has had little success in penetrating the limestones of the Eucla Basin in previous surveys. Several sets of recording parameters were tested, including 10 Hz geophones and lower frequency 4.5 Hz geophones as parallel spreads. Also, linear upsweeps were compared to low-dwell non-linear upsweeps designed to introduce more low frequency energy into the signal. Initial results from the testing program were encouraging. Production data were subsequently collected along the Trans Australia Railway access road as far as Haig, using Geoscience Australia' standard deep crustal seismic acquisition parameters.