Four people were seriously injured and another 22 had minor injuries when a Continental Airlines jet hit turbulence on a flight from Brazil to Texas, forcing the plane to make an emergency landing in Miami, Florida early on Monday, officials said. Continental Flight 128 was traveling from Rio de Janeiro to Houston with 168 people on board when it was diverted, Miami International Airport spokesman Marc Henderson said. Federal Aviation Administration spokeswoman Kathleen Bergen said the plane landed safely at 5:30 in the morning, after it reported hitting severe turbulence an hour earlier. Houston-based Continental did not immediately respond to messages left for a spokesman. Those not seriously injured would be flown on to Houston, the airport spokesman said. Henderson said the plane was scheduled to return to Houston, though he did not know what time.