Ocean Bottom Seismograph Observatory

Ocean Bottom Seismograph Observatory
Name	Ocean Bottom Seismograph Observatory
Type	Geophysical observatory
Field	Seismology

Ocean Bottom Seismograph Observatory is a class of subsea geophysical facility that records seismic waves on the seafloor using autonomous instruments. Developed from efforts by institutions such as Scripps Institution of Oceanography, Lamont–Doherty Earth Observatory, Woods Hole Oceanographic Institution, and British Geological Survey, these observatories enable studies of Plate tectonics, Earthquake sources, and Mantle structure beneath ocean basins. Instruments are used in campaigns associated with programs like Integrated Ocean Drilling Program, International Ocean Discovery Program, and Ocean Observatories Initiative.

Overview

Ocean bottom seismograph systems were conceived to extend observation networks of arrays such as Global Seismographic Network, United States Geological Survey, and regional deployments by groups including Geological Survey of Japan and Institut de Physique du Globe de Paris. Early prototypes built at Scripps Institution of Oceanography and Lamont–Doherty Earth Observatory evolved alongside technologies from Woods Hole Oceanographic Institution and industrial partners like Schlumberger and Kongsberg Gruppen. Deployments complement land-based datasets from stations of the International Seismological Centre and research cruises funded by agencies such as National Science Foundation and European Commission.

Instrumentation and Design

Typical instruments combine a three-component seismometer, a hydrophone, an inertial referencing system, and a data logger influenced by developments at National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration, and European Space Agency. Designs borrow pressure housings and release mechanisms proven by Alvin (DSV), ROV Jason, and HMS Challenger-era engineering. Power systems rely on battery technology advanced by firms like Panasonic and Saft Groupe S.A.; timing is synchronized using Global Positioning System references prior to deployment and cross-calibrated against networks such as International GNSS Service. Mechanical design considers standards from American Bureau of Shipping and materials research at Massachusetts Institute of Technology.

Deployment and Recovery

Deployment and recovery operations integrate shipboard capabilities exemplified by research vessels like RV Atlantis (AGOR-25), RV Roger Revelle, RRS James Cook, and RV Sonne. Mooring, glider, and free-fall options trace lineage to projects from Monterey Bay Aquarium Research Institute and Ifremer. Recovery often uses acoustic release technology developed with input from WHOI and suppliers such as Subsea 7; remotely operated vehicles like ROV Jason and ROV Hercules or human-occupied vehicles like Alvin (DSV) assist in complex retrievals. Coordination involves maritime authorities including United States Coast Guard and port operations at hubs like San Diego, Plymouth, and Papeete.

Data Acquisition and Processing

Raw seafloor records undergo preprocessing using toolchains influenced by software from IRIS (organization), USGS, and European-Mediterranean Seismological Centre. Processing workflows apply signal conditioning, tide correction informed by National Oceanic and Atmospheric Administration tide models, and noise suppression techniques developed in collaborations with Lawrence Livermore National Laboratory and Los Alamos National Laboratory. Seismic tomography, ambient noise correlation, and event detection leverage algorithms from Stanford University, ETH Zurich, and Caltech researchers, with data archived in repositories such as DataONE and distributed via networks like GeoNet. Metadata standards follow guidelines promoted by International Federation of Digital Seismograph Networks.

Scientific Applications

Seafloor seismology using these observatories has advanced understanding of Mid-Atlantic Ridge, East Pacific Rise, Nazca Plate, Juan de Fuca Plate, Subduction zone megathrusts like the 2011 Tōhoku earthquake and tsunami, and intraplate features beneath the Pacific Ocean and Indian Ocean. Studies have informed models of Mantle plume dynamics near Hawaii, crustal earthquake rupture processes observed in events such as the 2010 Chile earthquake and 2004 Indian Ocean earthquake and tsunami, and induced seismicity research connected to projects like Krafla and Groningen gas field studies. Multidisciplinary campaigns have integrated seismology with tomography from Ocean Drilling Program boreholes, heat flow studies coordinated with Lamont–Doherty Earth Observatory, and geodetic constraints from UNAVCO.

Operational Challenges and Limitations

Operational constraints include battery longevity influenced by manufacturers like Saft Groupe S.A., biofouling issues noted by researchers at Monterey Bay Aquarium Research Institute, and communication limits compared to cabled observatories such as NEPTUNE Canada and OBSEA. Data quality can be affected by ambient noise generated by shipping lanes near Panama Canal, weather-related swell studied by National Weather Service, and seismic coupling peculiarities identified near island arcs like the Aleutian Islands. International legal and logistical hurdles intersect with frameworks such as the United Nations Convention on the Law of the Sea and port-state controls enforced by authorities including Maritime and Coastguard Agency (UK).

Notable Observatories and Projects

Significant deployments and programs include arrays and projects run by Ocean Observatories Initiative, NEPTUNE Canada, SEAMON deployments coordinated by IRIS (organization and Scripps Institution of Oceanography, the Japan Agency for Marine-Earth Science and Technology campaigns, and collaborative initiatives between Lamont–Doherty Earth Observatory and Instituto Português do Mar e da Atmosfera. Landmark experiments include studies of the 2006 Kuril earthquake sequence, investigations along the Iceland rift by teams from University of Iceland, and broadband ocean-bottom campaigns associated with the Integrated Ocean Drilling Program.

Category:Seismology Category:Oceanography