  Modern optical atomic clocks along with the optical fiber technology
currently being developed can measure the geoid, which is the equipotential
surface that extends the mean sea level on continents, to a precision that
competes with existing technology. In this proceeding, we point out that atomic
clocks have the potential to not only map the sea level surface on continents,
but also look at variations of the geoid as a function of time with
unprecedented timing resolution. The local time series of the geoid has a
plethora of applications. These include potential improvement in the
predictions of earthquakes and volcanoes, and closer monitoring of ground
uplift in areas where hydraulic fracturing is performed.
