Non-technical summary: This study argues that the 1923 Ms=7.9 Kanto earthquake in Japan caused coseismic changes in the stress field in the Kanto region. An increase in the regional stress field in Odawara and central Boso coincide with clusters of aftershocks. A drop in the stress field around Tokyo agrees with the still ongoing seismic quiescence. We also compute the stress changes due to the earthquake on different sources of seismic hazard in the Kanto region and find that active faults in the Tokyo Bay area were affected by the 1923 earthquake. The stress level increased on Izu Peninsula, which may have triggered the 1930 Ms=7.3 Kita-Izu earthquake. Furthermore, an increase in the stress level on the Western Sagami Bay fracture is inconsistent with this structure's presumed delayed rupture. Finally, stresses were also raised on the down-dip extension of the 1923 rupture plane, and on the 1703 earthquake fault plane southeast of Boso Peninsula, bringing these structures closer to failure.

Figure caption: Change in Coulomb failure stress in the Tokyo Bay area computed with our 2-plane source model for the regional preferred orientation of failure (strike 250º, dip 35º and rake 90º) at different depth levels. The focal mechanism in the legend indicated the preferred orientation of failure with the red line representing the rupture plane. Seismicity shown is from the aftershock catalogue by Hamada et al. [2001] located between 0 and 40 km depth. The assumed coefficient of friction is 0.4.