The vertical response of an ocean bottom seismometer: Analysis of the Lopez Island vertical transient tests

A lumped-parameter model was developed to predict the response of an ocean bottom seismometer, resting on relatively non-stiff sediments, to vertical ground-motion. The model predictions were compared with the response of an instrument on a foundation of foam rubber to a sinusoidal input. Comparison of the model data to the measured Lopez Island vertical transient test data showed that bearing pressure of the instrument in a nonuniform vertical soil profile causes certain instruments to experience a shear modulus higher than the mean.