Analysis of the continuous GPS stations before and after the earthquake

We also processed GPS data from the 4 continuous stations currently operating in the Dominican Republic for the 2 weeks preceeding and following the September 22 earthquake. The objective is to check if these sites have been affected by coseismic displacements. Sites San Pedro de Macoris and La Vega are susceptible to significant coseismic displacement because of their relative proximity to the epicenter.

The resulting position time series are shown on Figure 6.2. There is no coseismic offset visible in the position time series, at the 2-3 mm level in the horizontal components, 5-6 mm level in the vertical component. Sites San Pedro de Macoris and La Vega are therefore too far from the epicenter to have been affected by coseismic displacements. Consequently, campaign sites located at a similar or greater distance to the epicenter are also unlikely to be affected by coseismic displacements.

Figure 6.2: Position time series for the 4 continuous GPS sites operating in the Dominican Republic for the 2 weeks preceding and following the September earthquake. Each point represents a position derived from a 24-hour solution, with an error bar representing its formal uncertainty. Top panels: NS component; middle panels: EW component; bottom panels: vertical component. The vertical dashed line indicates the day of the earthquake.