Earth Planets Space, Vol. 52 (No. 11), pp. 993-997, 2000LETTER
Peiliang Xu1, Seiichi Shimada2, Yoichiro Fujii3, and Torao Tanaka4
1Disaster Prevention Research Institute, Kyoto University at Uji, Uji, Kyoto 611-0011, Japan
2Natl. Res. Inst. for Earth Sc. and Disaster Prevention, Tennodai 3-1, Tsukuba, Ibaraki 305-0006, Japan
3Nippo Co. Ltd., 1-8-7 Kodai, Miyamae-ku, Kawasaki 216, Japan
4Meijo University, Nagoya, Japan
(Received December 6, 1999; Revised August 10, 2000; Accepted September 12, 2000)
Abstract: Historical geodetic measurements have been used to infer on the displacement and strain states locally or regionally. They are also often used to invert for other geophysical parameters. However, historical geodetic measurements have been known to contain significant scaling and orientation errors, which may even be different in different parts of a network. These significant error sources may result in producing a wrong (or at least, a misleading) displacement or strain field. When such a displacement or strain field is further used to invert certain geophysical parameters, mis-interpretations may be expected. Thus, in this paper, we will perform a theoretical analysis to answer the following three questions: (i) are displacements obtainable from historical geodetic data? (ii) are strains obtainable from historical geodetic data? and (iii) what geodynamical value do historical geodetic data have?