How do you know it isn't a historic earthquake hot zone, but has just been calm for the last 200 years?
To give you an example of what has happened in the past, outside of the time of human habitation and record-keeping ... there is an example in the Pacific Northwest, having to do with the Cascadia Subduction Zone. The scientists did not know before the 1990s that earthquakes of 9.0 to possibly 10.0 happened there, but they now know of them.
That’s an example of needing studies to find out. But right now, the main culprit are certain wells in Oklahoma. This is not a state where they very easily arrive at those conclusions, as this is an OIL STATE ... :-) ...