Intensity Level Descriptions

Seismic Intensity levels are determined by observations of ground shaking during an earthquake. The U.S.G.S uses a version of the Mercalli Intensity Scale that extends from Intensity Level One (I), the weakest, to Intensity Level Ten (X+), very damanging ground shaking. Intensity Lab reports use the USGS Intensity One (I) to Ten (X) scale. The following links provide descriptions of the types of shaking experienced at each Intensity level: