The updated crustal attenuation in North China using M_L amplitude tomography

We have updated the lateral variations of the quality factor Q₀ (Q at 1 Hz) beneath the crust of North China using M_L amplitude tomography with near three times data. The data were selected from the Annual Bulletin of Chinese Earthquakes (ABCE) in 1985−2009, including 26 283 M_L amplitude readings from 4 204 events recorded by 38 stations. The result is similar with previous research but has higher resolution. Estimated Q₀ values are consistent with tectonic and topographic structure in North China. Q₀ is low in the active tectonic regions having many faults, such as Bohai bay, North China basin, the Shanxi and Yinchuan grabens, while it is high in the stable Ordos craton. Q₀ values are low in several topographically low-lying areas, such as the North China, Taikang-Hefei, and Subei-Huanghai Sea basins, whereas it is high in mountainous and uplift regions exhibiting surface expressions of crystalline basement rocks: the Yinshan, Yanshan, Taihang, Qinling and Dabie mountains, Luxi and Jiaoliao uplifts. Quality factor estimates are also consistent with Pn and Sn velocity patterns. High velocity values in general correspond with high Q₀ and vice versa. This coincides with a common temperature influence in the crust and uppermost mantle.