Seismically induced water level fluctuations in the Wali Well, Beijing, China

Water level records from a high‐speed recorder in the Wali well have been compared with long‐period seismograms to study the response of the well to seismic waves. Water level oscillations caused by two teleseismic events have been studied. The data show that the peak gain of well water level relative to aquifer pressure occurred at periods of 19–23 s for both events, in contrast with previous theory that predicted peak gain at periods of 35–39 s for a well with 565 m open to the aquifer. We present a more exact analysis of the vertical flow field in the open part of the well bore, which yields a theoretical response with peak gain much closer to the observed periods. The more exact analysis shows that during the seismically induced oscillations little flow takes place more than 200 m below the top of the aquifer.