Monsoonal loading in Ethiopia and Eritrea from vertical GPS displacement time series

Vertical GPS displacement time series from 16 continuous sites over a period from 2007 to 2014 are compared to time series of monthly averages of liquid water equivalent thickness from the Gravity Recovery and Climate Experiment and precipitation from the Climate Research Unit to investigate hydrologic loading in Ethiopia and Eritrea. The GPS vertical time series record the presence of one or two rainy seasons, the amplitude surface displacements in response to monsoon water load, and phases consistent with a purely elastic response to a water load that accumulates throughout the rainy period. Comparison of observed amplitudes to those calculated for an average Earth model shows no systematic weakness related to the rift.