On estimation of earthquake magnitude in Earthquake EarlyWarning systems

Vladimir Sokolov, Friedemann Wenzel, Takashi Furumura
2009 Earth, Planets and Space  
Determination of earthquake magnitude from the initial P-wave portion of ground motion is the key problems for Earthquake Early Warning (EEW). We analyzed performance of scaling relations between one of the frequently used early warning parameters, so-called characteristic period τ C and moment magnitude M W in respect of (a) characteristics of datasets accumulated in various regions (earthquake depth, characteristics of network) and (b) variation of initial conditions applying for
more » ... ng for determination of the parameter τ C (length of Pwave window, number of used stations). The used data contain strong-motion records from 110 earthquakes (moment magnitude range 4.4-7.6) occurred in Japan and Taiwan. We show that, although the standard error of regression τ C = f (M W ) in general becomes smaller with the increase of the length of P-wave window (PL) and the number (N ) of averaged observations (stations), the uncertainty in estimation of M W given observed τ C does not decrease further for PL > 3-4 seconds and N > 3-4 stations. The information about earthquake depth also plays an important role in reducing the uncertainty of magnitude estimations. The table of confidence limits for estimations of the moment magnitudeM W based on observations of the characteristic period τ C is provided.
doi:10.1186/bf03352981 fatcat:m5wv7gyfuffpnneufgudbavkui