Seafloor sediment low-frequency P-wave velocity prediction with grain-size and mineral-composition constraints from the South Yellow Sea, China.

The P-wave velocity of seafloor sediment is critical for marine environmental protection, target detection, and resource exploration, yet predicting the velocity across diverse sediment types remains a challenge. To meet the demand for rapid estimation, we developed a calculation method parameterized by grain-size proportions (sand, silt, and clay fractions), and mineral composition (clay minerals, quartz, and feldspar), grounded in regional geological survey data from the South Yellow Sea. Applied to the Continental Shelf Drilling Program borehole2 (CSDP-2), the method was validated by comparing its velocity predictions with the measured values and with outputs from existing models (Wood, Buckingham, and Lee). The results indicate that velocity fluctuations are primarily attributable to local formation characteristics with no consistent depth-dependent trends. Our model yields P-wave velocities in better agreement with the measured vertical seismic profile data than the other models considered, with differences generally within 10% and notably high consistency in the upper 25 m below the seafloor. This model provides an efficient means of obtaining low-frequency P-wave velocities for unconsolidated granular sediments, especially sandy ones. Its utility extends to other marine settings, where geological information is available but direct velocity measurements lacking.