Evidence of large scale repeating slip during the 2011 Tohoku-Oki earthquake

The repetition of slip during rupture process of earthquake is a debate issue which had never been confirmed clearly in the past big events due to the lack of dense near‐field observations and limited resolution in time of source model. The 2011 M9.0 Tohoku‐Oki earthquake generated a wealth seismic records which provided us an unprecedented opportunity to study the rupture evolution of giant earthquake at a high spatio‐temporal resolution. Here we use teleseismic, local strong motion and near‐field coseismic geodetic data to investigate the source rupture process of this event based on the parallel inversion technique. The results reveal a broad slip zone with remarkable large scale repeating slip during the earthquake. The inverted source model shows several time periods of energy release with three main peaks. These energy bursts and temporal rupture snapshots suggest repetition of a large scale slip on the biggest asperity. This rupture behavior resulted in >50 m slips on the slip zone and prolonged the entire rupture process for a long duration of ∼160 seconds. The proposed source model is in a good agreement with the aftershock distribution and can interpret the characteristics of local strong motions. Further investigations of repeating slip during this event are crucial which will deeply transform earthquake science from dynamic point of view. Key Points Large scale repeating slip was found during the 2011 Tohoku‐Oki earthquake Repeating slip suggests by high resolution joint source inversion analysis The repetition of slip resulted in >50 m slips and complex rupture process