Multidisciplinary, autonomous, Lagrangian floats for seismology, ocean acoustics and marine environmental science

We have developed autonomous, Lagrangian floats that make seismo-acoustic measurements in the oceans, with mission durations of 4+ years and running (http://earthscopeoceans.org). Earthquakes generate seismic waves that traverse the solid earth, convert to acoustic waves when they hit the seafloor from below, and are recorded by the hydrophone on our “Mermaid” floats drifting at ~1500m depth.

In the long-term, we aim for dense and even global coverage of the oceans for seismology, following the model of oceanography’s Argo initiative, or of internationally federated seismometer networks on land. In order to grow the network, we are exploring synergies with oceanography and the marine environmental sciences.

We present technical developments towards the first multidisciplinary mission in 2024 in the Mediterranean, whose floats will run embedded applications in two frequency ranges: the seismic (~0.1-5 Hz) as well as the “conventional” ocean acoustics range (10 Hz to 30 kHz). It will feature detection and classification algorithms for earthquakes, rainfall, marine mammal vocalizations, and ship noise. While energy-limited, these seismological floats carry significantly larger batteries than Argo floats and allow for up to eight physical/chemical/other sensors and their analysis algorithms, whose concurrent needs are managed by a domain-specific language written for the purpose (Bonnieux 2020).

 

Reference: Bonnieux, S. (2020). Float for multidisciplinary monitoring of the marine environment. From business expertise to embedded codes (Doctoral dissertation, Université Côte d'Azur).