Success During the OOI NSF VISIONS13 Expedition

August 16, 2013

During the VISIONS'13 Expedition, three subnets were completed at this site (highlighted in blue). They include: 1) a medium-powered J-box MJ03B in the ASHES hydrothermal field, which is connected to two short-period seismometers; 2) an HD camera also in the ASHES hydrothermal field; and 3) a medium powered J-box MJ03E connected to two short-period seismometers. Over 20 km of extension cables, with lengths up to ~ 5 km, were successfully installed in 2013 using the ROV ROPOS. All extension cables and subnets were fully tested and are functional, awaiting to be connected to Primary Node PN3B. The remaining infrastructure will be deployed in during VISIONS'14, next year.

This short-period seismometer was deployed on a flat sheet flow ~ 1.3 km east of the ASHES hydrothermal field in 2013. The black ball in the yellow circle shows that it is perfectly level, helping to insure that the highest quality data comes off of this network. Axial Volcano is likely to be quite seismically active and we are anxious to get the real-time data on shore next year. This will help us understand magma and fluid migration in the subsurface of the volcano…and eventually these data may help us predict an eruption. Several earthquakes were detected in real-time during testing of these seismometers in 2013. Credit: UW/NSF-OOI/CSSF, ROPOS Dive R1635; V13.

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.