Sumatran EQ Groundwater Graph

The graph above is a groundwater level hydrograph from the Aurora, Missouri observation well showing water level fluctuations. The graph clearly shows a rapid seismically-induced fluctuation that occurred shortly after the earthquake waves from the Sumatra earthquake passed through Missouri on December 25, 2004. One theory for why this happened is that the passage of seismic waves alternately relaxed and compressed the bedrock and its pore spaces.