Successfully proven advancements in autonomous Ocean Bottom Seismometers: Güralp Aquarius

Abstract:

Increasing broadband seismic station density in marine environments is crucial for understanding local and distant seismic activity. Technical, logistical and financial constraints on using traditional Ocean Bottom Seismometers (OBS) have been substantially reduced by Güralp Systems through 25 years of research and development. The recently engineered and successfully commercially deployed Güralp Aquarius OBS system overcomes these barriers and redefines boundaries for offshore seismic research.

Aquarius is a portable autonomous OBS combining a broadband seismometer with wireless acoustic communication while deployed at depths of up to 6000m for up to 21 months. Communication on demand allows operators to retrieve specific data for download during deployment period, while a continuous record is preserved on the OBS for full analysis after retrieval. Possible surface acoustic modem platforms vary from fixed buoys with satellite communication, passing ships of opportunity, wave-gliders or small private boats for manned visits. Modular design allows configuration of additional hydrophone and pressure gauge sensors with acoustic modem variations available to suit operator priorities.

Well-proven digital feedback control allows Aquarius to operate at any angle, thereby reducing landing site risks while excluding noise inherently associated with gimbal-controlled levelling systems. Acoustic communication during installation allows operators to assess the quality of the landing site before committing or repositioning. During recovery, ultra-fast recharging facilitates rapid turnaround times for re-deployment (1-hour charge per month deployment) without returning to port.

Further avenues are being explored to adapt Aquarius technology for longer-term autonomous deployments, while current standard configurations continue to be deployed in major ocean basins.