The impact of floods and storms on the acoustic reflectivity of the inner continental shelf: A modeling assessment

摘要: Abstract Flood deposition and storm reworking of sediments on the inner shelf can change mixture grain sizes seabed thus its porosity, bulk density, compressional velocity reflectivity. Whether these changes are significant enough to be detectable by repeat sub-bottom sonar surveys, however, is uncertain. Here question addressed through numerical modeling. Episodic flooding a large versus small river over course century modeled with HYDROTREND using drainage basin characteristics Po Pescara Rivers (respectively). A similarly long stochastic record storms offshore both rivers simulated from statistics long-term mooring recording waves in western Adriatic Sea. These time series then input stratigraphic model SEDFLUX2D, which simulates flood beyond mouths. Finally, annual reflectivity across regions computed densities output SEDFLUX2D sound speeds mean seafloor size analytical Buckingham [1997. Theory acoustic attenuation, dispersion, pulse propagation unconsolidated granular materials including marine sediments. Journal Acoustical Society America 102, 2579–2596; 1998. shear fluidlike 103, 288–299; 2000. Wave propagation, stress relaxation, grain-tograin shearing saturated, 108, 2796–2815]. The modeling predicts reflectivities that 9 dB for muds farther offshore, values agree measurements sediment types. On local scales ∼100 m, maximum