We had a 14-mile journey today from Ensley to Norfolk Starr landing north of Tunica.
We placed the batteries that ran the seismic equipment data logger on a rubber mat
and placed aluminum foil around the data logger. We also hung the data transmission
cable that comes from the streamer over the water. No 60 Hz noise!! Again, elimination
of this 60Hz signal, which results in noise within the data, allowed us to see deeper
into the subsurface than would be possible otherwise.
Nothing crazy happened today. We did begin to get a good deal of floating debris
coming down the river, like tree limbs and logs that we needed to ensure did not get
caught on the deployed equipment. Rain was headed our way from Arkansas. Though
we completed our day’s survey before it rained, the cloud cover made for nice traveling.
To aid in monitoring the Chirp data, which allows us to see into the shallow subsurface
(<50 ft), we placed another laptop on the stern running ESRI®’s ArcGIS and a GPS to
follow the M/V Strong’s path relative to the riverbed structure, called bathymetry.
It helped. We believe much of the shallow structure we were seeing was underwater
sand waves forming on top of a previously deposited sandbar that had a denser surface
that could be gravel deposits, or an “armor layer” where the fines have been removed
by reworking of the material.