| Physical Attributes | Two 7075-T6 aluminum 9” x 38” pressure housings holding: (i) data-logger, WHOI-designed controllers, acoustic release board, batteries, and (ii) acoustic release board, lithium batteries. A 16“ aluminum sphere holds seismometer and leveling system. Leveling is via motorized gimbals. Air weight with/without anchor is 1,509 lbs/1,234 lbs. Syntactic foam floatation consisting of two 24” x 34” x 17” blocks with combined in-air weight of 675 lbs and a combined 375 lbs. |
| Data Logger | Quanterra Q8 6-channel data engine with 24-bit A/Ds. Simultaneous sample rates of 1,000, 500, 250, 200, 100, 50, 40, 20, 10, and 1 Hz. Dual (internal standard and external optional) removable USB flash drives, typical 32GB and 64GB (other capacities possible); 32GB high-reliability SLC SD card; 32GB high-reliability eMMC. All remotely accessible. |
| Clock | Continuously powered Seascan clock with power-cycled Teledyne Chip-Scale Atomic Clock (CSAC) to measure Seascan frequency. |
| Sensors | Nanometrics Trillium T-240 seismometer with a velocity response that is flat from 240 s to 35 Hz, OR, Nanometrics Trillium T-120 Horizon seismometer with a velocity response that is flat from 120 s to 150 Hz OR, Nanometrics Trillium Compact OBS with a velocity response that is flat from 120 s to 100 Hz. When deployed, the seismometer package is mechanically decoupled from motion of the OBS frame. Differential Pressure Gauge (DPG) long-period pressure sensor. |
| Recording Duration | Lithium battery pack for ~18 months recording at 100 Hz. Separate keep-alive battery for clock. |
| Operation | Operated in closed-housing mode i.e. programming of acquisition parameters, offloading of data, clock setting, etc, all done through penetrators. Pressure tubes carry an electronic vacuum gauge to ensure tubes are well sealed prior to deployment. |
