Where can I find information about tornadoes that have occurred in Tulsa and in Oklahoma?

The Storm Prediction Center of the National Weather Service includes maps, tracks, averages and summaries that apply to tornadic activity in the United States.  The Norman office of the National Weather Service keeps a historic list of tornado data by county.  The EF Scale became operational on February 1, 2007 and is used to assign a tornado a 'rating' based on estimated wind speeds and related damage.

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.

What is the name of the scale used to measure wind speeds in hurricanes?

The Saffir-Simpson scale measures the intensity of a hurricane. Wind speed is measured on a scale of 1-5 to give an estimate of potential property damage and flooding along the coast. The Categories are as follows:
Category One Hurricane: Winds 74-95 mph.
Category Two Hurricane: Winds 96-110 mph.
Category Three Hurricane: Winds 111-130 mph.
Category Four Hurricane: Winds 131-155 mph.
Category Five Hurricane: Winds greater than 155 mph.