Body wave magnitude

The space wave magnitude scale ( mB, of body wave magnitude English ) is a method for measuring earthquake magnitudes. It is based on the study of the motion of the surface through seismic waves that do not move on the surface, but in the bowels of the earth.

Beno Gutenberg developed in 1945 following dimensionless parameter for teleseismic body waves (body waves such as P, PP and S waves ) for periods T from 0.5 to 12 seconds:

A is the movement of the surface throughthe skywave measured analogous to the method of determination of the local magnitude of the maximum amplitude on the seismogram in micrometers, T is the period of the wave, and is a correction factor, which of the distance measurement from the epicenter, in degrees, the depth of the earthquake ( hypocenter ) and the instrument used depends.

Short-period body waves magnitude scale

With the introduction of the 1-second seismometers of the Worldwide Standardized Seismograph Network was at the National Earthquake Information Center usual, only the vertical components of the P- waves (PV ) to consider and incorporate the correction factor. In addition (eg in order to distinguish earthquakes from underground nuclear tests ) was determined the largest amplitude only within the first few cycles rather than over the entire waveform. This variant is called the Short-period body waves magnitude scale (mb, body- wave magnitude, short period ).

The determination of the magnitude by means of the short- periodic space -wave magnitude scale underestimates the magnitude of earthquakes with a magnitude of about 6.5, because the energy radiated by large earthquakes seismic waves is shifted into areas long period and so does not enter into the determination.

Source

• Peter Bormann: 3.2 Magnitude of seismic events. In: Peter Bormann (Ed.): New Manual of Seismological Observatory Practice NMSOP. revised edition. GFZ German Research Centre for Geosciences, Potsdam, 2009, ISBN 3-9808780-0-7, pp. 33-34, 48, doi: 10.2312/GFZ.NMSOP_r1_ch3.

Intensity scales European macroseismic scale ( EMS) | Environmental Seismic Intensity Scale - ESI 2007 ( INQUA Scale ) | Chinese seismic intensity scale ( Liedu ) | Medvedev Sponheuer - Karnik scale ( MSK) | Modified Mercalli scale (MM ) | JMA scale ( Shindo ) | Sieberg scale

Magnitude scales Codamagnitude Md | Energiemagnitude ME | Einheitsmagnitude m | JMA magnitude Mj / Mjma | local magnitude ( Richter scale ) ML | Mantelmagnitude Mm | moment magnitude MW | Oberflächenwellenmagnitude MS | Raumwellenmagnitude mB and mb ( short periodic)

Historic scales Mercalliskala | Mercalli - Sieberg Cancani scale ( MCS ) | Mercalli -Wood - Neuman - scale ( MWN ) | Medvedev scale ( GEOFIAN scale) | Ōmoriskala | Rossi - Forel scale ( RF)

• Earthquake scale