Earthquakes? In Texas?

Ok, people, this is Texas -- not California. Why in the world have there been four earthquakes -- very small ones -- in the Johnson County area in a week. Three of those were one a day for the last three days. The one yesterday was strong enough to cause an aftershock. Some people believe it is because of the gas drilling in the area. It seems there is a huge number of wells being drilled right now. The county government has hired a geologist to try to get to the root of the problem but it seems they are getting more frequent and a bit stronger each time. I don't know about you, but this doesn't sound good to me. Texas -- tornadoes, hurricanes, floods -- yes, but earthquakes? Let's hope this is just a fluke and not working into an ongoing problem. I like my feet flat on a stable ground, thank you very much.