Roger Bilham

Our collaborative investigations with Kandilli Observatory, Istanbul, involve measurements of strain and aseismic slip on the northern and eastern Anatolian faults to learn more about the relationship between earthquakes and fault creep. In December 2019 the largest creep event (10 mm) yet recorded on the northern Anatolian fault propagated eastward near Ismetpasa in seven sub-events with velocities of up to 2.3 m/s.  Surface after-slip in the Mw6.8 2020 Sivrice/Elazig earthquake on the eastern Anatolian fault commenced a few days after the mainshock and decayed with a time constant of approximately 20 days.  Unlike in previous afterslip episodes elsewhere, however, slip rates accelerated after local aftershocks and continues at low rates a year after the event. Slip was also triggered by this earthquake on the East Anatolian fault some 40 km east of the rupture zone initiating a creep event that propagated eastward at 0.26 m/s. Slip was triggered on the southern San Andreas fault following the 2019 Ridgecrest earthquakes and propagated southward eventually triggering minor seismicity near the Salton Sea.