Comment on “A Unified Seismic Catalog for the Iranian Plateau (1900–2011)” by Mohammad P. Shahvar, Mehdi Zare, and Silvia Castellaro

A recent paper in the March/April 2013 issue of Seismological Research Letters , “A Unified Seismic Catalog for the Iranian Plateau (1900–2011)” by Mohammad P. Shahvar, Mehdi Zare, and Silvia Castellaro (henceforth referred to as Shahvar et al. , 2013) provides a unified homogeneous earthquake catalog, for the period 1900–2011, particularly for seismic‐hazard assessment studies in Iran. They subdivide the territory of the Iranian plateau into two domains only according to seismicity to derive empirical relationships to convert the original magnitudes ( M s, m b, M L, and M N) to a uniform scale ( M w), applying standard least squares (SR) and inverted least squares (ISR) regression methods and orthogonal regression method (OR). Some contradictions in Shahvar et al. (2013) encouraged us to declare a few points. The distinction between seismotectonic zones is based on all available geologic, tectonic, geophysical, and seismological data. In other words, a seismotectonic zone is considered an area that under present‐day geodynamic regimes has an internally consistent tectonic setting and unified seismicity pattern (Ye et al. , 1993, 1995). Shahvar et al. (2013) claim that the Iranian plateau can de facto be divided into two domains only because seismicity in the Alborz and Central Iran zones show statistically undistinguishable features. In contrast, Karimiparidari et al. (2013) distinguish six seismotectonic zones based on Mirzaei et al. (1998) and Tavakoli (1996). It is noteworthy that the second author of the two concurrent inconsistent papers is in common. Based on Nowroozi (1971) and Bird et al. (1975), it is stated by Shahvar et al. (2013) that the continental Arabian shield subducts beneath the Zagros belt. However, local seismograph networks have found no reliable depths in the Zagros deeper than ∼20  km, even in places where deeper earthquakes were reported to have occurred (e.g., Niazi et al. , 1978; Tatar et al. , …