What is the name of the scale used to measure earthquakes?

Earthquakes are measured with the Richter Magnitude Scale developed by Charles F. Richter of California Institute of Technology in 1935. Here is a summary of the Richter scale:
Magnitude less than 3.5: Generally not felt, but recorded.
Magnitude 3.5-5.4: Often felt, but rarely causes damage.
Magnitude under 6.0: At most slight damage to well-designed buildings over small regions.
Magnitude 6.1-6.9: Can be destructive in areas up to 100 kilometers across where people live.

Who should I contact for Oklahoma earthquakes information?

Oklahoma Geological Survey Observatory, Number One Observatory Lane, POB 8, Leonard, OK 74043.
Phone: (918) 366-4152
Toll-Free: (800) 330-3996
Fax: (918) 366-4156
Website includes Oklahoma earthquake maps, catalogs, seismograms and spectrograms, a catalog of worldwide nuclear tests, a form to use to report an earthquake in Oklahoma or surrounding states, and links to seismic sites.