Diagram of the San Nicolas submarine landslide off the southern California coast

San Nicolas slide. (a) Enlarged slope gradient map of the San Nicolas slide with a semi-transparent bathymetric color overlay (extent shown in Figure 1). Map shows the locations of Chirp and MCS lines highlighted in panels (a and b), as well as the location of Ocean Drilling Program (ODP) Leg 167 Site 1013 (Shipboard Scientific Party, 1997). (b) MCS line 124 from USGS survey L490SC (https://walrus.wr.usgs.gov/namss/survey/l-4-90-sc/) crossing the San Nicolas slide. Image highlights a slide headwall scarp and downslope slide debris deposit. The location of the seismic line is shown in panel (a). (c) Left plots show smoothed log curves (10-point moving average) of multisensor track (MST) data (density, natural gamma ray), porosity data (from index properties), and the age model from ODP Leg 167 Site 1013 (Shipboard Scientific Party, 1997). Colored lines tie the Site 1013 data to Chirp data from EW9709 (Rolling Deck to Repository, 2015) and SR1701 (Rolling Deck to Repository, 2017), linking the age model and sediment properties to the San Nicolas slide debris and the drape layer capping the debris. The locations of the Chirp data are shown in panel (a).