There Was a Small Earthquake This Morning Northwest of Casper
I highly doubt you felt this, but there was a minor earthquake centered just northwest of Casper this morning.
The USGS reported that we had a 2.7 earthquake 38 miles to the northwest of Casper. Here's the USGS map showing the exact location.
It's not unusual for Wyoming to have earthquakes, but most are located in or near Yellowstone. There was a small tremor near Old Faithful today also.
You can always get the latest earthquake info from the official USGS website.