Detecting unconventional seismic signals related to subduction zone processes at depth in continuous ocean bottomseismometer (OBS) records requires the analysis and identification of noise due to instrumental problems, deployment sites or sea state conditions. The temporary OBS deployment at the Lesser Antilles subduction zone provides new insights into the feasibility of detecting unconventional signals such as non volcanic tremor (NVT), long-period (LP) or ultra-long period (ULP) events. Analysis of noise at an array comprising several sites and types of instruments and comparison with recordings on land shows transients in the noise. Episodes can be identified considering the diversity of sites and instrument types and comparing the seismic signals with meteorological and oceanographic data. In order to reliably detect NVT (1–10 Hz) originating from inside the solid Earth, one must first characterize noise induced by the activity of the atmosphere and hydrosphere at the sea-bottom as well as on land. The semidiurnal modulation of noise amplitude can be shown here not to be due to that of the NVT from a seismic source at depth which is related to the subduction interplate and whose activity is modulated by the tidal stresses as inferred for other megathrusts on emerged forearcs. Here, the semidiurnal modulation is rather due to the effect of the tides themselves, such as tidal currents, since they do not affect all types and all components of the unique multi-station array of OBS that could be deployed on this submerged forearc. The short period cut-off of the strong noise due to ocean surface infragravity waves increases to longer periodswith OBS depth, thereby increasing the observationalwindowwith lownoise to lower frequencies, and deep OBS sites may be advantageous for detecting LP events. ; This research has been supported by the European Union FP6 NEST (New and Emerging Science and Technology)-INSIGHT programme, under project “ThalesWas Right” nr. 029080, by the FrenchNational Research Agency (ANR) CATTELL program under project SUBSISMANTI and by the OBSISMER program including French National, Martinique Regional, and EU FEDER funding. Instruments included OBS pools of Géoazur (P. Charvis and Y. Hello) and INSU/IPGP (W. Crawford and S. Singh, L. Béguéry), of IfM-GEOMAR (E. Flueh) and AWI. Land seismometer FDF is a GEOSCOPE station of the GDSN broadband observatories maintained by GEOSCOPE and the Volcanological Observatory of Mt Pelée, Martinique, of IPG Paris. Shiptime was provided during cruises Sismantilles II of IFREMER's N/O Atalante (M. Laigle), OBSAntilles of IRD's N/O Antea (P. Charvis), TRAIL of the German F/S M.S. Merian (E Flueh and H. Kopp), and with light-house and buoy service-ships Pointe d'Enfer of DDE Martinique and Kahouane of DDE Guadeloupe, and fishing ship Oceana