Fig. 2: Temporal evolution of optical surface reflectance.

a–d is an area in the vicinity of the hexagonal ejecta (same footprint as Fig. 1c, d) and (e–h) is an area containing field-confirmed liquefaction-driven surface ejecta. a–c, e–g Optical imagery from three dates illustrating differences in surface reflectivity (a), (e) after a rain event, (b), (f) after a dry spell and before the earthquake, and (c), (g) following the earthquake (© 2019 Planet Labs PBC). d Blue areas and (h) green areas indicate pixels for which surface ejecta are collocated with injection wells and with field-confirmed liquefaction, respectively. i Surface reflectance over time for blue and green surface ejecta pixels shown in d and h. Points indicate the mean surface reflectance value and shaded areas indicates the standard deviation (refer to “Methods” section for details). Note the decrease in overall reflectance both following rain events (right y-axis) and the Ridgecrest earthquake, before which no rain was recorded.