PEREIRA, Colombia — Rescue crews and civilians painstakingly searched through rubble Tuesday in the hopes of finding survivors trapped under debris after a powerful earthquake left thousands missing in dozens of cities and towns in western Colombia . Colombian President Abelardo de la Espriella said at least 181 people died in the magnitude 7.4 earthquake that struck Monday. De la Espriella also said 1,136 homes were destroyed and yet more damaged. Colombia’s new president faces his first serious challengeThe earthquake presents the first major test for first-time officeholder de la Espriella, who entered office just days before the natural disaster. Her home city, Pereira, was one of the worst hit, and a wall inside the factory collapsed.