Four people suffered minor injuries from the latest quakes and little damage was reported, Iranian state television said.
The U.S. Geological Survey said seven of the quakes struck near the Iraqi city of Mandali, 120 kilometers northeast of the Iraqi capital. Mandali is right on the border between the two nations.
An eighth quake hit near Mehran in western Iran, about 90 kilometers southeast of Mandali in the sparsely populated Zagros Mountains that divide Iran and Iraq.
All the earthquakes that were centered around the Iran-Iraq border struck within an hour of each other in the early morning of January 11, the U.S. survey said.
Six had a preliminary magnitude of at least 5, it said, while two registered at magnitude 4. Scientists consider earthquakes of magnitude 5 as moderate.
Iranian authorities offered similar figures for the magnitude of the earthquakes on state television.
Iranian state television said that people rushed into the streets as the temblors hit. In Baghdad and Iraq's Kurdish region in the north, people said they felt the quakes and aftershocks.
All the earthquakes struck at a depth of 10 kilometers, a shallow level that can causes more ground shaking and potential damage, particularly in places without strict building codes, according to the U.S. agency. Earthquakes at magnitude 5 can cause considerable damage.
In November, a 7.3-magnitude earthquake struck the border region, killing more than 530 people and injuring thousands in Iran alone. In Iraq, nine people were killed and 550 were injured, all in the country's northern Kurdish region, according to the United Nations.
The November earthquake hit hardest in the Kurdish town of Sarpol-e-Zahab in the western Iranian province of Kermanshah, about 80 kilometers from the sites of the latest quakes.
Many buildings collapsed or sustained major damage in the November quake. While the Iranian government has offered loans for rebuilding homes that were destroyed, many people are still living in tents or shipping containers amid cold winter weather.
Iran sits on major fault lines and is prone to earthquakes.
Other parts of Iran were hit by minor quakes on January 11, the U.S. agency said. It said a magnitude 4.9 quake hit Iran's southern province of Kerman before dawn, followed by a late afternoon quake of 4.8 magnitude.
The agency said another 4.6 magnitude temblor struck late on January 10 in Kermanshah Province. No injuries or damage were reported.
With reporting by AP, Reuters, and AFP