We report on a broad-band high-resolution attenuation model for the North China Craton and surrounding regions based on regional <it>Lg</it>-wave data. Vertical broad-band waveforms recorded at 39 stations from 176 crustal earthquakes are collected to extract the <it>Lg</it>-wave amplitude spectra between 0.05 and 10.0 Hz. We use the dual-station method to generate a preliminary <it>Q</it><inf><it>Lg</it></inf> model and use it as the initial model. Then, we combine the dual- and single-station data together to jointly invert the <it>Q</it><inf><it>Lg</it></inf> distribution and <it>Lg</it> source excitation functions. These inversions are conducted independently at individual frequencies without using any <it>a priori</it> assumption about the frequency dependences in <it>Q</it><inf><it>Lg</it></inf> and source terms. The maximum spatial resolution is approximately 1° × 1° in well-covered areas for frequencies between 0.05 and 2.0 Hz. The <it>Q</it><inf><it>Lg</it></inf> image is then used to determine the relationship between the attenuation and different geological structures. Results show an average <it>Q</it><inf>0</inf> (1 Hz <it>Q</it><inf><it>Lg</it></inf>) of 374 for the entire North China Craton with an increasing trend from east to west. Average <it>Q</it><inf>0</inf> values are 337, 361 and 421 for the east, central and west blocks, respectively. For the surrounding regions, the Eastern Tibetan plateau has a very low <it>Q</it><inf>0</inf> of 188, while the Northeast China Plate and the Tianshan–Xingmeng fold belts are characterized by high <it>Q</it><inf>0</inf> values of 506 and 424, respectively. We also investigate regional variations of the <it>Lg</it> attenuation in low-frequency band between 0.2 and 1.0 Hz.
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Zhao et al. (2013) studied this question.
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