Beneath 5000 m of water midway between Hawaii and California, the Hawaii‐2 Observatory (H20) rests on the seafloor (Figure 1). Telemetry and power come to this pioneer, deep‐ocean scientific observatory via a retired telephone cable, Hawaii‐2, donated by AT&T to the Incorporated Research Institutions for Seismology (IRIS) Consortium for the benefit of the scientific community. H20 is the first Global Seismographic Network (GSN) station on the seafloor.With a suite of wet‐mateable connectors on a junction box (j‐box), H20 offers marine scientists a new opportunity to deploy and operate remote instrumentation in the middle of the ocean.

A permanent deep ocean scientific research facility-the Hawaii-2 Observatory (H2O)-was installed on the retired HAW-2 commercial submarine telephone cable in September 1998. H2O consists of a seafloor submarine cable termination and junction box in 5000 m of water located halfway between Hawaii and California. The H2O infrastructure was installed from a large research vessel using the Jason ROV and standard over-the-side gear. The junction box provides two-way digital communication at variable data rates of up to 80 kbit/s using the RS-422 protocol and a total of 400 W of power for both junction box systems and user equipment. Instruments may be connected by an ROV to the junction box at 8 wet-mateable connectors. The H2O junction box is a "smart" design, which incorporates redundancy to protect against failure and allows full control of instrument functionality from shore. Initial instrumentation at the H2O site includes broad-band seismometer and hydrophone packages.

No abstract

No abstract

Real time observations of waves and current at the Martha's Vineyard Coastal Observatory (MVCO) from bottom mounted MAVS current meters permit critical events to be captured for subsequent analysis. Storm waves associated with winter northeasters and tidal and wind-driven current generate hottom stress that may fluidize the bottom. Vector velocity and pressure measurements will be made 75 cm above the bottom at two locations, at 12-meter depth and at 15-meter depth 2-km farther offshore. Power for these instruments will he supplied from nodes in the MVCO network and data from each instrument will be transmitted to the node for forwarding to shore on the network over an optical fiber. The benefit of the observatory lo our ability to capture critical events is the power for continuous high-speed sampling and the capacity of onshore based loggers for storing data for indefiNte deployment. Critical storm events will he selected for analysis, as in autonomous deployments, hut continuous sampling and logging over extended periods give us more opportunities to distinguish conditions that affect the sediment and'attennate waves.