Earthquakes are caused by movement on faults. It is important to understand the past behavior of faults in Colorado in order to understand what is the future hazard.
Paleoseismicity is the discipline of trying to determine the past movement behavior of faults.
Sackungen are a special category of faults that disrupt the ground surface in glaciated, alpine areas. They are not interpreted to extend very deep into the crust and are probably not capable of generating earthquakes. However, they can potentially yield information on past earthquakes on nearby faults.