How does magnitude scale work

It is a base logarithmic scale. Privacy Statement Disclaimer and Copyright. Staff Search. Earthquakes Earthquakes at a Plate Boundary. New Zealands Largest Fault. Earthquakes and Faults. New Zealand Earthquakes. Major Faults in New Zealand. Monitoring Earthquakes. Seismic Activity. Contact Us. Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing. Felt quite noticeably by persons indoors, especially on upper floors of buildings.

Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibration similar to the passing of a truck. Duration estimated. Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably. Felt by nearly everyone; many awakened.

Unstable objects overturned. Pendulum clocks may stop. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures.

Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Since moment magnitude can describe something physical about the event, calculated values can be easily compared to magnitude values for other events.

The moment magnitude is also a more accurate scale for describing the size of events. Since magnitude scales are logarithmic, an increase of one unit of magnitude on a magnitude scale is equivalent to an increase of 10 times the amplitude recorded by a seismograph and approximately 30 times the energy. Search form Search. Client Login. Who is ESG?