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Description:
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Paula Burgi
Remote sensing observations of the 2019 Ridgecrest, California, earthquake sequence revealed a significant amount of surface ejecta in the nearby Searles Lake, including one area where the surface ejecta was arranged in a repeating hexagonal “honeycomb” pattern. This pattern is collocated with injection wells from a solution mining operation, suggesting anthropogenic activities influenced the spatial distribution of surface ejecta. Lithology, geotechnical soil behavior, and the spatial distribution of long-term InSAR-derived subsidence indicate that surface ejecta in Searles Lake is not likely related to liquefaction. We propose a process, similar to liquefaction, that results in surface ejecta: (1) dissolution of evaporites increases the void/cavity space that is filled with fluid, (2) ground shaking causes void/cavity collapse (i.e., a volume reduction), (3) the collapse increases the fluid pressure, and (4) the increased pressure results in fluid flow to the surface. |