Earthquake duration magnitude

Earthquake Duration Magnitude ({{M|d}}) development

In 1965, Solovev{{Citation | doi-access=free}} used coda duration for the first time to estimate the Richter magnitude of local Californian earthquakes. Based on their study, they suggested that it is appropriate to estimate the magnitude of local earthquakes using signal duration. More recently, the development in instrumentation led to the use of signal duration to estimate the coda magnitude () for earthquakes recorded on short-period vertical seismographs. Numerous studies determined the relation between coda duration and magnitude for different regions of the World. According to a recent study by Mandal et al. (2004),{{Citation estimation is quite stable for local earthquakes ranging from magnitude 0.0 to 5.0.

Md empirical relationships

{{M|d}} empirical relationships

In two most recent investigations using statistically stable samples for Italian earthquakes (approximately 100,000 events over the period 1981–2002 in the Richter local [] magnitude range of 3.5–5.8){{Citation

M_d = 2.49*log_{10} (T) - 2.31 + (Station\ correction\ factor) (Castello et al., 2007)

M_d = 0.08log_{10} (T)^2 + 1.7log_{10} (T) - 0.87 (Mandal et al., 2004)

Where is coda duration magnitude, and T is the coda duration in seconds.

ML from Md

{{M|L}} from {{M|d}}

Although conversions between empirically derived "sensitive" seismic parameters such as earthquake magnitude scales is mathematically cautioned as well as physically limited, some seismologists such as Brumbaugh{{Citation

M_L = 0.936 * M_d - 0.16 \pm 0.22

References