Magmatic intrusions often produce ground deformation that can be studied by geodetic techniques. In the past two decades, many volcanic dike and sill emplacements (sometimes associated to eruptions) in different tectonic settings have been analyzed through InSAR. However, in only a few cases, the post-intrusive behavior has been studied. Here we analyze the post-diking deformation in Harrat Lunayyir, which is a mononogenetic volcanic field located in western Saudi Arabia on the eastern margin of the Red Sea Rift.Between April and July 2009, an intensive seismic swarm occurred in the area with many earthquakes above magnitude 4 and the largest earthquake of Mw 5.7. InSAR data showed that the earthquake swarm was triggered by the emplacement of a dike intrusion that stopped only ~1 km below the surface. Dike length was estimated to be ~7 km and with a maximum opening 4 m. Above the intrusion, a ~10 km long and ~5 km wide graben formed during the activity with up to 1 m of fault slip on the border faults. In the post diking phase up to present, micro-sesmicity (0