M. S. Marlow Shawn V. Dadisman 1988 <p>Analysis of a 24-channel seismic-reflection data collected near Mussau Island, Papua New Guinea, shows a high-amplitude, negative-polarity reflection that we believe is from the top of a magma chamber. &nbsp;The reflecting horizon lies at a depth of about 4.4 s subbottom and can be traced laterally for 2.6 km. &nbsp;On shot gathers, the reflection demonstrates normal moveout appropriate for an in-place event. &nbsp;The frequency spectrum of the reflection shows a decrease in high-frequency content when compared to the sea floor reflection, as would be expected for a deep subsurface event. &nbsp;The polarity of the reflection event is negative, suggesting that the reflection horizon is the top of a low-velocity zone. &nbsp;Magnetic data indicate that the ridge containing the reflecting horizon is magnetic, and the geology of Massau Island suggests that the ridge is volcanic in its origin. &nbsp;We speculate that the high-amplitude reflection is from the top of a magma chamber some 7-11 km deep.</p> application/pdf en Circum-Pacific Council for Energy and Mineral Resources Geophysical study of a magma chamber near Mussau Island, Papua New Guinea chapter