AUV-collected multibeam bathymetry and Chirp sub-bottom profiles from two transects across the Sur Pockmark Field

Two multibeam and Chirp subbottom surveys (Morro Tie West -20220203m1 and Morro Tie East -20220203m2), over 50 km long, were collected roughly paralleling the shoreline, transecting the Sur Pockmark Field offshore Big Sur California. These data were collected in February of 2022 from the R/V Rachel Carson using an Autonomous Under Water Vehicle (AUV) developed at the Monterey Bay Aquarium Research Institute (MBARI) specifically for seafloor mapping. The vehicle carried a Reson 7125 400kHz multibeam sonar and an Edgetech 2205 1-6 kHz Chirp sub-bottom profiler allowing the vehicle to collect multibeam bathymetry and Chirp sub-bottom data simultaneously. The AUV was preprogrammed to proceed to more than 50 waypoints during the dives while traveling at 3 knots and maintaining an altitude of 50 m off the seafloor. In this mode, the AUV obtains multibeam bathymetric coverage at a vertical resolution of 0.15 m and a horizontal footprint of 0.87 m, and Chirp seismic-reflection profiles with a vertical resolution of 0.11 m. These data were collected after initial AUV surveys were completed in 2019 and thus are not archived with the other similar datasets stored at the U.S. Geological Survey here https://doi.org/10.5066/P97QM7NF.

All of these data were collected to support the research article:

 Lundsten, E. Paull, C.K., Gwiazda, R., Dobbs, S., Caress, D.W., Kuhnz, L.A., Walton, M., Nieminski, N., McGann, M., Lorenson, T., Cochrane, G., Addison, J. C. (in-press) Pockmarks offshore Big Sur, California provide evidence for recurrent, regional, and unconfined sediment gravity flows. Journal of Geophysical Research: Earth Surface

The multibeam data files (MorroTieWest_Topo2m_UTM.grd and MorroTieEast_Topo2m_UTM.grd) were processed, cleaned and gridded using open-source software MBSystem. The position of the surveys may have some small lateral offsets that have not been corrected. The data files are in netCDF grid format (.grd) with horizontal 2 m resolution and are projected into UTM zone 10N. The grid files are compatible with GMT programs and MBSystem software. 

The sub-bottom Chirp data sets (MorroTieWestChirp.7z and MorroTieEastChirp.7z) consist of several post script (.ps) files that contain images of the processed sub-bottom Chirp data. Continuous straight runs of Chirp data are broken into numbered lines, and those are broken into sections. Files are named by line number and section. As an example, line 1, section 1 from Morro Tie East is labeled as 20220203m2_0001_01_sectionplot.ps. A map of AUV tracklines with line and sections numbers are included: 20220203m1_SBP_nav.ps and 20220203m2_SBP_nav.ps. Multiple .ps files from each survey are grouped and zipped for ease of transfer. The .ps files can be viewed in Adobe Illustrator.