These interpretations are used to explain the precipitation of iron locally around the vent site and to make comparisons with analogous environments associated with the precipitation of iron such as in other seafloor locations, soils and ancient iron formations.
Further, the sonar pinger tracks differences in height from the ocean floor of the bottom electrode, and this real time monitoring allows us to adjust the wire length to maintain a nearly constant altitude of the bottom electrode, which ensures an even coupling with the seafloor from location to location.
We can calculate average V p/V s in the sediment beneath the OBS JF1 using Equation 1, where d t (time lag), tc (two-way time of conversion point below the OBS), and tsf (two-way time of seafloor at OBS location) is 1.6 ± 0.1, 10.05 ± 0.05, and 9.12 ± 0.05, respectively.
We collected information on the thickness and permanency of sea ice, snow cover, current velocity and light transmission to the seafloor at each location (Appendix S1).
Fig. 1 Seafloor bathymetry and locations of multi-channel seismic (MCS) reflection lines (gray thin) in Nankai Trough margin off southwest Japan.
Data location and seafloor imaging.
The shipboard antenna mounts connect sub-aerial GPS positioning to underwater acoustic ranging that determine the centimeter-level location of seafloor transponders.
This is particularly important considering that the location of seafloor debris accumulation areas still need to be precisely pinpointed13 and that the environmental consequences of this pollution are still poorly understood44,45.
Tsunami observations can provide good timing constraints on the location of seafloor motions, potentially constraining slip at shallow depths, but the long wavelengths involved do require accounting for the full spatial extent of source motions (Lay et al., 2011b).
Submarine landslides, debris flows and turbidity currents are significant geohazards for seafloor infrastructure in many locations around the world.
