Satellite images show ethnic cleanout in Iraq
Minority Sunni Arabs were driven out of many neighborhoods by Shi'ite militants enraged by the bombing of the Samarra mosque in February 2006. The bombing, blamed on the Sunni militant group al Qaeda, sparked a wave of sectarian violence.
"By the launch of the surge, many of the targets of conflict had either been killed or fled the country, and they turned off the lights when they left," geography professor John Agnew of the University of California Los Angeles, who led the study, said in a statement.
"Essentially, our interpretation is that violence has declined in Baghdad because of intercommunal violence that reached a climax as the surge was beginning," said Agnew, who studies ethnic conflict.
Some 2 million Iraqis are displaced within Iraq, while 2 million more have sought refuge in neighboring Syria and Jordan. Previously religiously mixed neighborhoods of Baghdad became homogenized Sunni or Shi'ite Muslim enclaves.
