A magnitude 3.9 earthquake shook the Morongo Basin Wednesday morning. The earthquake happened at 9:56 a.m. and it was centered 16 kilometers northwest of Morongo Valley, according to the United States Geological Survey. It was initially reported as a 4.1 magnitude before being downgraded. A series of smaller earthquakes followed. They were as little as magnitude 1.0 and as large as magnitude 2.5.