Earthquake Moment Magnitude Scale

The seismic moment defines how much force is needed to generate the recorded waves.

Earthquake moment magnitude scale. Earthquake size as measured by the richter scale is a well known but not well understood concept. Moment magnitude scale the moment magnitude scale mms was devised by scientists after the 1960 chilean earthquake and the 1964 alaskan earthquake. Hanks and hiroo kanamori similar to the local magnitude scale m l defined by.

Use appropriate media player to utilize captioning. The moment magnitude scale considers the. These great subduction zone earthquakes broke along fault lines that were hundred of kilometers long.

The moment magnitude scale was designed to produce a more accurate accounting of the total energy released by an earthquake and it calculates the earthquake s magnitude more accurately than other measures such as the richter scale m l the body wave scale m b and the surface wave scale m s. Denoted explicitly with m w or mw and generally implied with use of a single m for magnitude is a measure of an earthquake s magnitude size or strength based on its seismic moment a measure of the work done by the earthquake it was defined in a 1979 paper by thomas c. It is the energy of the earthquake at the moment it happens.

Like the similar and older richter scale it is logarithmic with a base of ten. Earthquake measurements to get a better idea of strength of the shaking and damage the moment magnitude scale was developed to capture all the different seismic waves from an earthquake to worldwide seismic networks. Since 1970 the moment magnitude scale has been used because it supports earthquake detection all over the earth.

Scientists used these two sets of information and other data collected in the field to determine the. The moment magnitude scale is a way to measure the power of earthquakes. The moment magnitude scale includes the area of the fault s rupture and the slippage along the fault to determine the size of the earthquake s moment.

A srt file is included with the downloiad. The moment magnitude scale mw or m w developed by kanamori 1977 and hanks kanamori 1979 is based on an earthquake s seismic moment m 0 a measure of how much work an earthquake does in sliding one patch of rock past another patch of rock. The moment magnitude scale mms.

Moment magnitude scale measuring great earthquakes. The size of the earthquake waves is determined by reading seismograms at reporting stations.