PALU, Indonesia—A week after a major earthquake brought devastation to Indonesia’s Sulawesi island, Ichsan Hidayat found his sister and her baby daughter, who were killed when their neighborhood became a churning sea of mud and debris.
Hidayat was not on Sulawesi on Sept. 28 when the 7.5 magnitude earthquake struck, triggering a phenomenon called soil liquefaction, which turns the ground into a roiling quagmire.
