August 16, 2013
Last night we began our transit to Newport Oregon to pick up some equipment and then conduct work at Primary Node PN1C, ~ 40 miles west of Newport. The many days of hard work and very long hours at Axial Volcano and at the base of the subduction zone by the University of Washington Applied Physics engineers and School of Oceanography scientists and students, the R/V Thompson crew and the ROPOS Team paid off with very successful field deployments. During the Regional Scale Nodes VISIONS’13 NSF-UW program, we installed:
- Over 22,000 m of fiber optic extension cables on the seafloor — all tested and functional
- Three medium powered junction boxes (Slope Base – MJ01A; Axial Summit – MJ03B, and MJ03E) – all tested and functional
- Four short-period seismometers at Axial – all tested and functional
- A high definition video camera at the ASHES hydrothermal filed – tested and functional
- A 3D thermistor array at ASHES – tested and functional
- A bottom-pressure tilt sensor near Eastern Caldera – to be cabled and tested next summer
- 2 pressure sensors (Slope Base and Axial Base) – 1 tested and functional; 1 to be connected next year
- 2 benthic flow meters at Southern Hydrate Ridge
- 2 caissons (Southern Hydrate Ridge summit and Slope Base) for follow-on broadband installations next year
The installations at Axial include three nearly complete subnets, both of which were fully tested by powering them up and communicating to them with ROPOS – both were shown to be fully operational.
1) The first subnet is installed at the ASHES vent field and includes a 4 km cable extending from near Primary Node 3B and connected to the Medium powered J-Box (MJ03B) within the field. This J-Box includes connections to a 1.3 km extension cable across the caldera connected to a short-period seismometer and a 50 m extension cable with another short-period seismometer. A battery-powered thermistor array was also deployed there for a 1-year test.
2) The second subnet is also in the ASHES field and includes another 4 km cable (10 Gbs) extending from near PN3B that is connected to the high definition camera at the base of the Mushroom hydrothermal chimney.
3) The third subnet is installed at Eastern Caldera and is a geophysical array to monitor seismicity within the volcano and inflation and deflation of the seafloor. Installed infrastructure at this site includes a 635 m extension cable from near PN3B that is connected to MJ03E. Two short-period seismometers are connected to the J-Box via a 1262 cable and a 581 m cable, respectively. Next year the bottom pressure-tilt instrument and a broadband seismometer with a hydrophone will be installed, completing this subnet.
4) The fourth subnet is located at the Slope Base site, which includes a 576 m cable extending from near Primary Node PN1A to the J-Box MJ01A, and a cabled current meter and pressure sensor. Next year a broadband seismometer, also hosting a hydrophone, will be installed and connected at this site (there is already a caisson there).
Other highlights of the program include the detection of earthquakes during testing of both the ASHES and Eastern Caldera subnets (followed by analyses of the earthquakes by William Wilcock, University of Washington and students while at sea aboard the Oceanus, streaming of live HD imagery for several hours to the Internet from the seafloor camera deployed at the ASHES vent field, and documentation of profound geological and plume changes at the Southern Hydrate Ridge site with large, recent collapse zones and very intense bubble plumes.