I study #Paleoseismology, and #EarthquakeGeology. To study the faults and earthquakes that happened decades, centuries, or thousands of years back, we generally do excavations. These will expose the sediments and rocks deformed allowing us to infer how much deformation a given earthquake caused, its likely magnitude, and when did it happen. Thus, telling us how BIG and FREQUENT earthquakes can be on that fault (at that location). This is much needed to help understand hazards and mitigate risk.