We present a procedure for rapid determination of an earthquake moment magnitude,M_wp, at regional distances from the P-wave first arrivals based on Tsuboi et al. (1995, 1999) and Kanjo et al. (2006). We apply an automated windowlength selection and use a variable P-wave velocity instead of a constant value to make a better estimation for Mwp magnitude. This procedure is applied to 46 earthquakes with magnitude (M_w) greater than 4.8, which have been recorded and analyzed for Global Centroid Moment Tensor (Global CMT; the Global Centroid Moment Tensor Project database was searched using www.globalcmt.org/CMTsearch.html [last accessed July 2012]) solutions between 2008 and 2011 by the Prime Ministry Disaster and Emergency, Presidency National Earthquake Department (AFAD). Our results show good agreement between the M_wp and M_w magnitudes (about ±0:27 mu), and we expect this procedure can be used for the rapid determination of moment magnitudes of regional earthquakes.
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