The 1906 M7.8 California earthquake occurred 117 years ago: 1906-04-18 13h12mUTC. Here is recent seismicity (1984-2022) west of San Francisco. The 1906 hypocenter was likely in the yellow box, perhaps within the deep, linear trend of recent earthquakes (yellow).
Apr 18, 1906 San Francisco earthquake: my work on the likely hypocenter location & complex ruptures in the focal region https://pubs.geoscienceworld.org/ssa/bssa/article/98/2/846/350139/Location-of-the-Focus-and-Tectonics-of-the-Focal
Apr 18, 1906 San Francisco earthquake: Sparse timing data (including quick reading of wall clocks by local observers!) are sufficient to estimate the hypocenter location within about 10-20km (red cloud) - the epicenter is quite near San Francisco. https://pubs.geoscienceworld.org/ssa/bssa/article/95/3/861/103179/A-Reanalysis-of-the-Hypocentral-Location-and
