Real‐Time Magnitude Characterization of Large Earthquakes Using the Predominant Period Derived From 1 Hz GPS Data

E-ISSN： 1944-8007|45|2|517-526

ISSN： 0094-8276

Source： GEOPHYSICAL RESEARCH LETTERS, Vol.45, Iss.2, 2018-01, pp. : 517-526

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Abstract

AbstractEarthquake early warning (EEW) systems' performance is driven by the trade‐off between the need for a rapid alert and the accuracy of each solution. A challenge for many EEW systems has been the magnitude saturation for large events (M_W > 7) and the resulting underestimation of seismic moment magnitude. In this study, we test the performance of high‐rate (1 Hz) GPS, based on seven seismic events, to evaluate whether long‐period ground motions can be measured well enough to infer reliably earthquake predominant periods. We show that high‐rate GPS data allow the computation of a GPS‐based predominant period (τ_g) to estimate lower bounds for the magnitude of earthquakes and distinguish between large (M_W > 7) and great (M_W > 8) events and thus extend the capability of EEW systems for larger events. It has also identified the impact of the different values of the smoothing factor α on the τ_g results and how the sampling rate and the computation process differentiate τ_g from the commonly used τ_p.