GEOLOGY

Detailed explanation-1: -In the United States, we use the Modified Mercalli (MMI) Scale. The Mercalli Scale is based on observable earthquake damage. From a scientific standpoint, the magnitude scale is based on seismic records while the Mercalli is based on observable data which can be subjective.

Detailed explanation-2: -A seismograph is the primary earthquake measuring instrument. The seismograph produces a digital graphic recording of the ground motion caused by the seismic waves. The digital recording is called a seismogram. A network of worldwide seismographs detects and measures the strength and duration of the earthquake’s waves.

Detailed explanation-3: -Note: The Modified Mercalli scale is designed to describe the effects of an earthquake, at a given place, on natural features, on industrial installations and on human beings. The intensity differs from the magnitude which is related to the energy released by an earthquake.

Detailed explanation-4: -Richter Scale. While the Mercalli scale describes the intensity of an earthquake based on its observed effects, the Richter scale describes the earthquake’s magnitude by measuring the seismic waves that cause the earthquake.

Detailed explanation-5: -Although numerousintensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli (MM) Intensity Scale.