It isn't that simple. There is not one magnitude above which damage will occur. It depends on other variables, such as the distance from the earthquake, what type of soil you are on, building construction, etc. That being said, damage does not usually occur until the earthquake magnitude reaches somewhere above 4 or 5. Learn more: Earthquake Magnitude, Energy Release, and Shaking Intensity
How do volcanoes erupt?
Can you predict earthquakes?
What is the difference between a tsunami and a tidal wave?
What is a landslide and what causes one?
The USGS monitors and conducts research on a wide range of natural hazards to help decision-makers prepare for and respond to hazard events that threaten life and property.