Preface for article collection "10 years after the 2011 Tohoku earthquake: a milestone of solid earth science".

The preface for the article collection "10 years after the 2011 Tohoku earthquake: a milestone of solid earth science" highlights the scientific discoveries made since the earthquake, thanks to near-field observations and existing knowledge about the northeastern Japan arc. The earthquake revealed dynamic frictional behaviors of the subduction interface and provided insights into subduction zone dynamics. The collection of research on the Tohoku earthquake is expected to benefit the understanding of subduction earthquakes worldwide. The preface also mentions various research papers included in the collection, covering topics such as coseismic stress drop, afterslip, seafloor observations, slow earthquake activity, tsunami deposits, paleoseismology, and numerical modeling of the earthquake cycle. Ongoing research on postseismic deformation and historical research on earthquake occurrence are also discussed. The authors express their appreciation to the reviewers and the editorial board for their contributions to the special issue. [Extracted from the article]