General Description and Scientific Significance

The IDOOS III expedition, conducted in 2025 aboard the Chilean Navy's oceanographic research vessel AGS-61 Cabo de Hornos, had as its primary objective the acoustic download of data from the FETCH AZA system and the recovery of two bottom pressure sensors that had been continuously operating in the Atacama Trench.

The expedition extended the time series initiated in 2023 and evaluated the stability of the submarine geodetic records obtained within the Atacama seismic gap. In addition, a new Lander was deployed to continue long-term observations of the hadal environment and deep-ocean processes.

Scientific Objectives

• Perform the acoustic download of data from the FETCH AZA system.
• Recover two bottom pressure sensors.
• Extend the submarine geodetic observation time series.
• Monitor seafloor deformation in the Atacama Trench.
• Deploy the Lander for hadal observations.

Onboard Technology

• AGS-61 Cabo de Hornos research vessel.
• FETCH AZA bottom pressure sensors.
• Acoustic communication and data download systems.
• Autonomous Lander.
• CTD-Rosette system.
• Deep-ocean oceanographic instrumentation.

Participating Institutions

• Millennium Institute of Oceanography (IMO).
• Oceanographic Instrumentation Center (CIO).
• University of Concepción.
• Chilean Navy.