Earthquake in New York City lasting 20 seconds

Small earthquake felt in Queens, New York Lasted for about 20 seconds. The house was actually swaying side to side. No damage done. Will watch out for subsequent quakes. Hope this is not a prequake. It's a big deal for us, especially in our neighborhood where the infrastructure is old. Old gas mains led to explosion of a couple of houses several years ago. We certainly don't need tremors to weaken what is already bad.