Figure 1. Here, we calculate the stress transferred by the two mainshocks to the surrounding faults. The blue areas had the highest fault slip, and so become stress shadows, or regions for which future shocks are inhibited, as first described by Harris and Simpson (1996). The surrounding red areas, also called trigger zones, are brought closer to failure. (a) Failure on the Sürgü-Çardak Fault is promoted by about 3 bars. (b) After the magnitude-7.5 event strikes, additional stress is transferred back to the magnitude-7.8 rupture, causing a further stress increase on some fault sections, and a decrease in others. Note that the stress scale differs in the two panels to make the effects more evident.