Seismic intensity scales

Seismic intensity scales measure how strong an earthquake feels to people in a given area. Seismologists use different scales to measure how strong an earthquake is because different people experience earthquakes differently. The two main scales are the Modified Mercalli Scale (MMI) and the Richter scale. The MMI scale measures the intensity of the shaking felt by people in different locations, while the Richter scale measures the energy that is released by an earthquake. An earthquake can be very strong but if it is far away from people it will not be felt and so the MMI scale will be lower than the Richter scale. The MMI scale goes from 1 to 12, with 1 being the weakest and 12 being the strongest. Earthquakes measured around 3 or 4 on the MMI scale are usually only felt indoors. Earthquakes measured 5-6 on the MMI scale are usually felt outdoors and can cause some damage to buildings. Earthquakes measured 7 or higher may cause significant damage or even complete destruction.