JOSHUA - There is steam rising from the blacktop road in rural Johnson County.
It's summer. It's Texas. They're used to the ground below them sizzling, but not shaking.
"Never felt anything like that before," said Dana Bruce, a lifelong resident of Joshua, describing what she felt Sunday at a potluck lunch at Lane Prairie Baptist Church.
"We had tables down the middle, a food line going for our potluck," explained fellow church member Cathy McCarthy. "I had just gotten our plates and forks."
Terry Potter, 18, was in the gym, at a table.
"I was sitting here eating," he said.
Suddenly, the ground beneath all of them began to move.
"I was walking through this hallway," Bruce said, "and about right here, I stopped because it went..." She paused and made a waving motion with her arms.
"The ceiling was rattling," she continued. "It felt like you were in a little box and somebody was shaking you around. Everybody said, 'I think that was an earthquake!' We were looking around, it didn't last very long, so we just went back to eating."
Lane Prairie Baptist has been in Joshua 141 years, and it's doubtful there had ever been a Sunday service with an earthquake.
"I didn't really like it," Bruce said, with a laugh.
There was no explanation. And certainly no warning, but maybe in the future there could be.
Right now, no one can predict when an earthquake will occur.
"It's not possible, in the sense that an average person believes in predictions," said UT-Arlington Earth and Environmental Studies Professor Glen Mattioli.
While he can't predict them, he can explain them. Especially the big ones.
Mattioli has been working in and studying the Caribbean since the late 1970's. He and other UTA researchers are putting in a system of GPS receivers there, where an active fault line has produced horrifying tragedies, like the January 2010 earthquake in Haiti. Those receivers record movements of plates deep beneath the surface, and as scientists track that movement, they uncover what happens just before a big quake strikes.
Through this plotting of the past Mattioli hopes to someday have a better grasp of what's coming in the future.
"There is hope in the scientific community that we will get to a stage that we can give more certain estimates about magnitude, location, maybe even timing of earthquake events," he said.
Mattioli and other UTA researchers leave for Nicaragua in two weeks for intense study there.
But Johnson County has no GPS receivers to study. There is nothing recording movement, because the ground's never moved. This week, there were three minor quakes in three days: Saturday, Sunday and Monday.
Mattioli and other scientists say it is possible the movement is linked to re-injection wells associated with gas drilling, but that's a theory yet to be proven.
Since there are no plate boundaries near North Texas, "basic ideas don't work to explain why earthquakes would occur," he said.
"There's a pretty good indication these events are clustered in time and space with some anthropogenic activities, but unless you have a dedicated, highly-sensitive network in place, it's hard to get accurate locations and do proper modeling," Mattioli said.
"Now though, we do have a hypothesis to test," he said of the re-injection well theory.
Potter said he'd lived in Joshua his entire life and he'd never felt anything like what he felt Sunday. He doesn't particularly want to feel it again.
"Especially while I'm eating," he said.