The Geophysics Institute at Eduador's National Polytechnic School said the quake registered a magnitude of 4.9 when it struck at 12:41 a.m. local time.
Local media reported that many “shanty towns” along the Guayaquil River collapsed during the shaking.
A subsequent 4.3 magnitude aftershock before dawn on Sunday caused two older homes in the port’s low-income neighborhood of El Guasmo to collapse.
An elderly woman who lived in one of the wrecked houses was treated by paramedics for minor injuries and shock. A young boy sustained an arm injury during Sunday’s jolt.
The U.S. Geological Survey placed the epicenters about 30 miles (45 km) west-northwest of Guayaquil, and 170 miles (275 km) southwest of the capital, Quito.
Both occurred at depths of about 47 miles (75 km).
