The series of quakes has levelled whole villages, burying families and leaving thousands homeless as winter approaches.
Residents in Herat, the capital of an Afghan province by the same name, had just begun returning to their homes – after days of sleeping outside fearing aftershocks – when the latest earthquake hit around 8am (02:30 GMT) on Sunday.
The United States Geological Survey said the quake had an epicentre 33km (21 miles) northwest of Herat City.
Save the Children said four people had died and that Herat Regional Hospital received 153 injured. Structures in the Baloch area of Rabat Sangi district have collapsed. Several villages have been destroyed, according to the aid group. Authorities have given lower casualty numbers.
Sayed Kazim Rafiqi, 42, a Herat resident, said he had never seen such devastation before, with a majority of houses damaged and “people terrified”.
Rafiqi and others headed to the hospital to donate much-needed blood. “We have to help in any way possible,” he said.