ABNORMAL L(G) CODA Q IN BEIJING AREA

This paper presents the results of an L(g) coda Q study in the Beijing area of China. The data originate from the Beijing Telemetered Network; the Q (= Q0f(eta)) measurement technique is the stacked spectral ratio method (SSR). The study area, roughly 250 km in radius, is sampled repeatedly by scattered coda waves recorded at epicentral distances between 190 and 422 km. The results point to 1-Hz Q (Q0) as low as 150 and eta as high as 0.95, in a jarring incongruity with the ambient attenuation characteristics about the study region. The L(g) coda Q0 is found varying inversely with eta. The unequivocality with which such a relationship becomes unravelled comes about somewhat unexpectedly given the small spatial confine of the study area. If high coda attenuation (low Q0) and high eta are taken to correlate with a high level of tectonic activity in a broad sense, a view generally held to be statistically accurate, then the Beijing area belongs to the same league in Eurasia, whose members include such well known ''earthquake countries'' as the Himalayas, the Tibetan Plateau, the Burmese Arc, and the Tianshan Mountains.