NUMERICAL SIMULATIONS FOR RARE ICE GOUGE DEPTHS

Numerical simulation methods are developed to compute ice gouge depths associated with given return intervals for subsea structures of any geometric shape. In particular, the structure can be a pipeline that is not aligned along the direction in which gouge data have been gathered or a subsea wellhead or other seafloor structure that occupies a region of any geometric shape. One input to this simulation is the areal gouge generation rate, which is the number of new gouges generated per unit area per year. Since linear gouge generation rate data are available in the public domain for the Beaufort Sea, a formula was developed to convert linear gouge generation rate to areal gouge generation rate. This paper also presents formulas that are useful to obtain closed form solutions for rare gouge depths, knowing the areal gouge generation rate. Several example simulations are presented in this paper to illustrate the methodology. When closed-form solutions are available, the simulation results are very close to the closed-form solutions. The simulation method provides both point estimates and interval estimates to rare ice gouge depths.