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We acknowledge the comments of R. Das and H. R. Wason on our paper published in Seismological Research Letters 80 (4), 609–627 (hereafter Yadav et al. 2009). We respond first to those points we can agree on before dwelling on misunderstandings or misconceptions raised. But first, a general comment. Standard deviations of classical magnitude estimates range at best between 0.1 and 0.2 magnitude units (m.u.). This is the reason why magnitude values are generally published only with a precision of 0.1 m.u. Calculating three decimals, as in Table 1 of Das and Wason, is unrealistic. Accordingly, the International Association of Seismology and Physics of the Earth's Interior (IASPEI) Working Group on Magnitude Measurement considers procedures that reproduce magnitude values within 0.1 m.u. as compatible and in agreement with requirements for standard-conforming measurements. For easier reference we number our comments, and for the sake of brevity we will refer to their comment as “ D&W.” 1. D&W correctly point to a typesetting error in Table 2 of Yadav et al. (2009): The value 5.4 for the event of 10 January 1986 stands in the wrong column. It has to be mb ,NEIC. As such it has been used to calculate the correct Mw ,HRVD( m b,NEIC) proxy. 2. D&W based their relationship between MS ,ISC and MS ,NEIC on many more data pairs from the region (87) than we did (28). Accordingly, their formula is better constrained. Yet, conversion differences in the applicable magnitude range of these formulas vary only between 0.04 and 0.09 magnitude units (m.u.). This is not significant. 3. Equations (3) and (4) derived by D&W between Mw ,HRVD and MS ,NEIC, respectively Mw ,HRVD and MS ,ISC agree better with each other than ours. Such good agreement was … |
