Following Schutz(1988), the response of two masses connected by a spring to a gravitational wave with amplitude httxx,00 is controlled by
The solution to this equation when is
If is large with respect to , will approach zero and will be proportional to httxx.
I make a crude assumption that a column in the earth will react like a spring. Away from resonance, the response of the earth to a gravitational wave will be proportional to the strain ,where is colatitude and is longitude as given by Hellings (1992). This strain on a sphere for t=0 is shown at an exaggerated scale in Figure .
Figure 5 An exaggerated view of the strain on the earth caused by a gravitational wave. The function plotted is .
If this response is close to the correct response, the strain of the earth recorded by the IDA network can be predicted. Figure shows the response of the earth as it would appear to the available stations to a source at position 43 of the grid in Figure , using these approximations.
Figure 6 The response of the IDA stations to a gravitational wave source at position 43 of the grid in Figure 11. Each trace corresponds to a station in the IDA array.