• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Deception Island; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.505.8144; http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea078.pdf

Summary Deception Island is a volcanic island with a flooded caldera that has a complex geological setting in Brans-field Strait, Antarctica. We use P-wave arrivals recorded on land and seafloor seismometers from airgun shots within the caldera and around the island to invert for the P-wave velocity structure along two orthogonal profiles. The results reveal a low-velocity anomaly beneath the caldera with a maximum anomaly of ~-1 km/s extending from the seafloor to ~5 km depth. Refracted arrivals suggest a>1-km-thick layer of sediments and unconsolidated lavas infilling the calde-ra. Synthetic inversions show that this layer accounts for only a small portion of the velocity anomaly, implying that there is a significant region of low velocities at greater depths. Further synthetic inversions and melt fraction calcula-tions suggest that the caldera is underlain by an extensive region of magma that extends downwards from <2 km be-neath the seafloor.