State officials said the OPEC member's oil production was not affected by the quake but the principal refinery of Esmeraldas, located near the epicenter, had been halted as a precaution.
The Ecuadorian quake followed two quakes that struck Japan on the opposite side of the Pacific. A 7.3 magnitude tremor struck Kumamoto province early on Saturday, killing at least 32 people, injuring about a thousand and causing widespread damage. The first quake, late on Thursday, killed nine.
Ecuador and Japan are both located on the seismically active "Ring of Fire", which sweeps from the South Pacific islands, up through Indonesia, Japan, across to Alaska and down the west coast of the United States and Central and South America.
A smaller 6.1 magnitude quake hit the Pacific island nation of Tonga on Sunday, with no immediate reports of damage.