Migration of Displacement Anomalies on the Flanks of a Preparing Earthquake Source: A Swing Model

—The geomechanical modeling of the stress-strain dynamics before the 2019 M = 7.1 Ridgecrest earthquake, Southern California, revealed an alternating pattern of maximum displacement anomalies that develop around the ends of the future rupture, simulating the process of “swinging” in the epicentral zone of the earthquake. These results, together with the existing theoretical concepts of crustal block structure with block interaction, are used to build a “swing” geomechanical model based on the stick-slip phenomenon in a three-block configuration. The parameters of the model are related to the rheological properties of the Earth’s crust in the area of destruction of the bridging isthmus (a patch), which determines the source size of the seismic event.