Saudi Arabia sits mostly on the stable interior of the Arabian Plate, but its western edge is anything but quiet. The plate is rifting away from Africa along the Red Sea, and this active spreading gives the country's western provinces genuine volcanic and seismic activity despite its largely aseismic reputation.
Vast volcanic fields known as harrats, such as Harrat Rahat and Harrat Lunayyir near Medina, cover the western highlands with young lava flows. A well-documented eruption occurred near Medina in 1256 CE, and a 2009 earthquake swarm at Harrat Lunayyir, driven by rising magma, forced tens of thousands to evacuate and confirmed the region is far from dormant.