The generation and recording of high (up to 200 Hz) frequencies is normally restricted to shallow engineering applications. In this paper, an experiment is described in which high frequencies are emitted and recorded from depth levels of interest for oil and gas exploration. The experiment was performed in the Sultanate of Oman and consisted of a stationary geophone spread of 300 3 300 m, with a source line of length 2 km shooting into the geophone box (Figure 1). The test area was a flat gravel plane selected to avoid complications with high static anomalies. An overview of the test site is shown in Figure 2.