Research > Deception Island

In January 2005, we were supported by the National Science Foundation to participate in a tomography experiment on Deception Island on the Antarctic Peninsula in collaboration with scientists from the University of Granada, Spain. Deception Island is an active volcano located in a complex geological setting whose geometry makes it ideal for seismic tomgraphy. The goal of the experiment was to obtain a seismic image of the volcano, and use this to get the thermal structure and distribution of melt.

An aerial picture of Deception Island. The island is about 15 km in diameter.

The seismic experiment was undertaken in January 2005. A Spanish research vessel sailed to Deception Island with an international group of scientists, organized by the University of Granada in Spain.

The Spanish R/V Hesperides inside Port Foster (the Deception Island caldera

A total of 14 Ocean bottom 1Hz seismometers were installed around the island as well as inside the caldera, and 142 land seismometers, some of them of 4Hz and some broadband, were installed on the island.

The deployment of a seismometer during the Deception Island experiment

Two rounds of shootings were completed both inside the caldera and around the island with a 3500 cubic inch array of 6 airguns yielding a dataset comprising 4495 shots.

Airgun shooting plan around Deception Island. A dense grid of shots was also obtained within the caldera

At the University of Washington, graduate student Tami Ben Zvi has worked to obtain a two-dimensional tomographic images of the deeper structure beneath Deception Island while Daria Zandomeneghi has obtained three-dimensional images of the shallower structure.

East-west cross-section showing a P-wave tomographic image for Deception Island.

The results show that there are is a substantial low velocity zone beneath the caldera which extends from the seafloor to at least 5 km depth. The upper 1 km of the anomaly is a result of a thick sedimentary and pyroclastic sequence that fills the caldera while the rest is a result of a magma chamber that extends downwards from <2 km depth and may contain up to 20 cubic kilometers of melt. A paper on the two-dimensional tomographic results is being revised for publication in the Journal of Volcanological and Geothermal Research (PDF file) and a second paper describing bathymetric data collected during the experiment is in press in Antarctic Science (PDF file). Daria Zandomeneghi who was a graduate student at the University of Granada Spain has also recently submitted a manuscript on three-dimensional tomography to the Journal of Geophysical Research.