Compare the closely related, though much larger (103 cm.) figure of a standing Guanyin, excavated at Laohucheng village in Tongguan County, Shaanxi, 1963, included in the exhibition, Buddhist Sculpture from China: Selections from the Xi'an Beilin Museum - Fifth through Ninth Centuries, China Institute, New York, 2007, pp. 83-4 and illustrated on the cover.
See another larger figure of Guanyin, also said to be from Shaanxi, shown standing in a similar pose on a lotus-petal base and similarly adorned with elaborate jewelry, dated to the Sui dynasty by Akiyama and Matsubara in Arts of China, vol. II; Buddhist Cave Temples, New Researches, Tokyo, 1969, p. 162, no. 153. In his discussion of Sui dynasty sculpture in The Arts of China to AD 900, Yale University Press, 1995, W. Watson notes that some examples "present an unusual frontal outline: a narrow high waist and a greatest breadth near to the knees", the latter being very true of the present figure. He also points out that the Guanyin type from Shaanxi and western China, while upright, has a more relaxed and natural stance, and is richly decorated, with "head-ribbons and body-scarves".
Technical examination report available upon request.