Calculation of Seismogenic Seiches Using Potential Wave Theory

This paper describes a method for estimating the amplitude of seismogenic seiche oscillations in enclosed bodies of water on land. The method is based on an analytical solution to the problem within the framework of linear potential wave theory. For a rectangular channel filled with an ideal fluid and moving under the influence of an earthquake according to an arbitrary law in the horizontal direction, explicit expressions are obtained for calculating the displacement of the free surface of the fluid, the flow velocity field, and the potential and kinetic energy. The response of the fluid in the channel to a model “seismic” movement and to a real seismic event—the Chilean earthquake of September 16, 2015 (Mw = 8.2)—has been analyzed. The input data are horizontal velocity components recorded by four South American stations of the IRIS network which are located at epicentral distances from 10.3° to 40.5°. Simple formulas are proposed for estimating the amplitude of seiche oscillations based on seismic records and reservoir parameters.