© via NBC newsThis picture was taken by a passenger aboard the Southwest flight as it prepared to make an emergency landing.
Flight 812, carrying 118 passengers, landed safely at Yuma Marine Corps Air Station/International Airport at 4:07 p.m. after experiencing "rapid decompression," the FAA said.
"Upon safely landing in Yuma, the flight crew discovered a hole in the top of the aircraft," Southwest said in a statement. "There are no reported customer injuries. One of the flight attendants, however, received a minor injury upon descent."
The cause of the decompression was not known, FAA spokesman Ian Gregor said. An FAA inspector from Phoenix was en route to Yuma.
Terrorism was not suspected because an FBI spokesman in Sacramento, Steve Dupre, said "it appears to be a mechanical issue."
Some passengers aboard the plane recounted moments of terror after landing in Yuma. They said they heard what sounded like an explosion that opened a hole in the cabin.
"They had just taken drink orders when I heard a huge sound and oxygen masks came down and we started making a rapid descent," a passenger named Cindy told Sacramento TV station CBS13.
"They said we'd be making an emergency landing. There was a hole in the fuselage about three feet long. You could see the insulation and the wiring. You could see a tear the length of one of the ceiling panels."
"You can see daylight through it," a passenger identified as Brenda Reese told Sacramento TV station KCRA by cellphone.
A Sacramento resident told CBS13 she received a text message from her husband, who was aboard the flight: "Plane going down. Love you."
She said she heard from her husband a few minutes later after the plane landed safely. The woman's husband said there was an explosion or a hole in the plane, the TV station said.
Shawna Malvini Redden, another passenger aboard the flight, tweeted after landing: "One flight attendant was injured and a couple passengers passed out but nothing major."
Passengers became aware there was a problem when they heard a noise and felt the rush of wind and oxygen masks started dropping in the cabin, according to Reese.
She said a few people passed out "because their oxygen wasn't working. It was scary."
Reese said flight attendants went around the cabin aiding passengers. Emergency medical technicians were on board the plane treating passengers after it landed in Yuma.
Gina Swankie, a spokeswoman for Sacramento International Airport, said Southwest was sending another plane to Yuma to take the passengers to Sacramento.
"I want to get home and hold my three children," Reese said.
Southwest said it will work with the Federal Aviation Administration and the National Transportation Safety Board to investigate the cause of the mishap.
This story contains information from The Associated Press and NBC News.
Could this have been an miniscule, errant bollide or cometary fragment that tore a small hole in the plane?