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Mermaids are autonomous floating seismometers drifting with the ocean current at a pre-specified depth. CLS is providing the service of data collection through IRIDIUM, but also proposes to host the data

Measuring seismic waves over 71% of the Earth surface (i.e., the oceans) has been possible for some years now thanks to the MERMAID system (Mobile Earthquake Recorder in Marine Areas by Independent Divers). Those autonomous floating seismometers are drifting autonomously with the ocean current at a pre-specified depth. They are equipped with hydrophones to collect seismograms and programmed to surface whenever their onboard computer recognizes a strong earthquake signal. Once at the surface, they transmit their data via Iridum satellite and take their position from GPS. Then they use their pump and oil reservoir to reduce their volume and dive back down, to depths as large as 4000 m.

They record additional data during their dive, such as water temperature but can also measure salinity as well if equipped with a Conductivity-Temperature-Depth sensor. The Mermaid trajectories are used also by oceanographers to monitor abyssal currents, in addition to their primary seismological use.

About CLS

CLS is providing the service of data collection from MERMAID floats through IRIDIUM, but also proposes to host the data. CLS is the only Iridium Value-Added Reseller (VAR) providing this dedicated service for metocean platforms (not only for floats) using Iridium RUDICS communications, allowing users to easily and securely manage their communications with the instrument.

mermaid buoys drifting
A plot of the full array of 23 Mermaids launched by Geoazur, Princeton, Jamstec and Kobe during the first year of SPPIM. Colour indicates days since June 14, 2018 (start date of the campaign).(Credit GeoAzur)
mermaid launch
Launch of a Mermaid (Credit GeoAzur)

The newly upgraded CLS hosting service offers enhanced operationality for the users: they have direct access to platform accounts, and data safety is enhanced through strict. This service is managed by CLS data processing center, monitored 24/7, with active redundancy on 2 separate backup processing centers, to ensure a maximal efficiency and data safety.

About EarthScope Oceans (ESO)

EarthScope Oceans is an organization founded by a multidisciplinary group of geoscientists coordinating national efforts to create an international global network of seismological sensors that monitor the Earth from within the oceanic environment. Decisions can be made by its different committees on instrument development, science objectives, data management, and outreach. Founding members are Geoazur, IPG Strasbourg, Princeton University (US), IRIS (US), Jamstec (Japan), Southern University of Science and Technology of Shenzhen (China), and Kigam (Korea).


The OSEAN (SAS) company is specialized in the study and the manufacturing of innovative systems performing in harsh environment. OSEAN’s headquarters are located in TOULON, on the French Riviera. OSEAN’s team has years of experience in the design of scientific and military underwater systems.


Mermaids are the first instruments capable of seismometry in quasi-real time in the oceans. They were developed by engineers from Geoazur and OSEAN, supported by an Advanced Grant from the European Research Council, in close collaboration with scientists from the Université de la Côte d’Azur and Princeton