Redeployment of a hydroacoustic observatory intended to monitor the low-level seismicity associated with the Indian seafloor spreading ridges and to the intraplate deformation of the southern Central Indian basin, and to monitor the presence and migration patterns of large baleen whales in the southern Indian Ocean. This observatory is now composed of 9 distant moorings equipped with autonomous hydrophones. This network has been redeployed every year since its initial deployment early 2010.  The objectives of this cruise were to redeploy the network for another year (2019) in an improved geometry.