The Intensity Lab

Seismic intensity describes the level of shaking at a particular site caused by an earthquake. The United States Geological Survey (USGS) reports seismic intensity on a scale from one (I) to ten (X). The higher the seismic intensity number, the greater the level of shaking.

Seismic intensity information can be used to help make informed decisions after an earthquake. In the United States, earthquake information reporting tends to focus on the earthquake magnitude. The goal of the Intensity Lab is to widen the reporting and use of seismic intensity.

Seismic intensity is not the same as earthquake magnitude. Each earthquake has one magnitude. However, each earthquake can produce many seismic intensities because the effects of the earthquake vary by location. Typically, the farther a location is from the earthquake, the lower the seismic intensity.

Intensity Lab distributes seismic intensity reports through:

Intensity Lab seismic intensity reports are intended to broaden understanding and use of seismic intensity reporting, but Intensity Lab reports are not official and they may not be reliable after an earthquake. Please use the USGS Earthquake Information to obtain official earthquake information.

The Intensity Lab Email Contact:

Last updated: November 22, 2014