SAN MARCOS, Guatemala — A 7.4-magnitude earthquake rocked Guatemala on Wednesday, killing at least 48 people as it toppled thick adobe walls, shook huge landslides down onto highways, and sent terrified villagers streaming into the streets of this idyllic mountain town near the border with Mexico. One hundred people were missing, and hundreds were injured.

The quake, which hit at 10:35 a.m. in the middle of the work day, caused terror over an unusually wide area, with damage reported in all but one of Guatemala’s 22 states and shaking felt as far away as Mexico City, 600 miles to the northwest.