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Surface Wave Magnitude Using Epicentral Distance

The surface wave magnitude scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements in Rayleigh surface waves that travel primarily along the uppermost layers of the Earth. It is the ground velocity associated with the maximum trace amplitude in the surface­wave train, as recorded on a vertical component seismogram.

The surface wave magnitude is proportional to the logarithm of the product of the distance from station to epicenter and the maximum ground velocity.

Formula

QuantityVariable[Subscript["M", "S"], "Unitless"] == 3.3 + 0.7209288399593979*Log[Quantity[0.008992805755395683, "Kilometers"^(-1)]*QuantityVariable[Subscript["R", "epi"], "Distance"]] + Log[Quantity[1/(2*Pi), "Seconds"/"Nanometers"]*QuantityVariable[Subscript["V", "max"], "Speed"]]/Log[10]

symbol description physical quantity
MS surface wave magnitude "Unitless"
Repi distance from station to epicenter "Distance"
Vmax maximum ground velocity "Speed"

Forms

Examples

Get the resource:

In[1]:=
ResourceObject["Surface Wave Magnitude Using Epicentral Distance"]
Out[1]=

Get the formula:

In[2]:=
FormulaData[ ResourceObject["Surface Wave Magnitude Using Epicentral Distance"]]
Out[2]=

Use some values:

In[3]:=
FormulaData[ ResourceObject[ "Surface Wave Magnitude Using Epicentral Distance"], \ {QuantityVariable[ \!\(\*SubscriptBox[\("M"\), \("S"\)]\),"Unitless"] -> 6.1`}]
Out[3]=

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