2013 34 ANNALS OF SHANGHAI OBSERVATORY ACADEMIA SINICA No. 34, 2013 1986 1998 1,2,3 1,3 2,3 4 ( 1. 100049 2. 200030 3. 100012 4. 430071 ) 1986 1998 32 20 ( M 5) 20 15 0.15 a P631.4 + 43 1 [1,2] 1925 0.18 [3] (plumb line variations PLV) 1966 1976 [4] ( ) [5,6] 1980 [7] [8] [9] 2013-02-27 2013-05-08
34 1986 1998 31 2 1986 1998 24 27 N 99 102 E 3 3 1985 LaCoste 2 3 1998 32 ±7 µgal ±10 µgal (1 Gal = 0.01 m/s 2 ) Kringe 3 3 61 61 0.075 [8] ξ η = 1 2π 2π π 0 0 cos A gq(ψ) dψda, (1) sin A ξ, η g A g Ψ Q(Ψ) (Meinesz) Q(Ψ) = ρ 2γ sin Ψ d S (Ψ), (2) dψ ρ ρ = 206 265 γ Ψ d cos2 dψ S (Ψ) = 2 sin Ψ [ csc Ψ 2 + 12 sin Ψ 2 32 sin2 Ψ 2 + 3 12 sin 2 Ψ ( 2 ln sin Ψ 2 + Ψ )] sin2 2 1 + sin Ψ 2. (3) 1 [10] 1 [11]
32 2013 1 1986 1998 20 (M 5) 2.5 (http://www.csndmc.ac.cn/newweb/index.jsp) 2 1 1986 1998 ( ) ( ) (Mb) 1 1986/07/10(86.52) 01:15:30.0 27.45 101.48 5.9 2 1987/05/18(87.38) 02:03:09.4 26.22 100.26 5.0 3 1988/01/10(88.03) 07:43:13.5 27.23 100.96 5.6 4 1988/04/15(88.29) 10:58:14.9 26.36 102.76 5.5 5 1988/11/06(88.85) 13:15:44.3 23.16 99.55 7.2 6 1988/11/15(88.87) 10:28:13.7 23.18 99.71 5.4 7 1989/05/07(89.35) 00:38:17.9 23.52 99.62 6.2 8 1990/01/26(90.07) 22:46:19.8 23.37 100.23 5.0 9 1990/02/14(90.12) 05:49:31.5 23.23 99.62 5.3 10 1990/08/18(90.63) 13:38:17.6 27.03 101.23 5.0 11 1991/04/11(91.28) 20:32:18.5 27.23 101.13 5.1 12 1991/07/22(91.56) 11:58:52.9 24.92 99.13 5.2 13 1992/02/11(92.11) 00:56:15.5 27.57 101.06 4.5 14 1992/12/22(92.98) 03:30:18.0 26.36 100.73 5.5 15 1993/07/17(93.54) 09:46:32.0 27.98 99.70 5.6 16 1995/10/23(95.81) 22:46:50.2 26.02 102.24 6.6 17 1996/02/03(96.09) 11:14:19.6 27.34 100.25 6.9 18 1996/03/13(96.20) 03:52:13.5 27.01 100.31 5.0 19 1996/09/24(96.73) 19:24:47.6 27.30 100.37 5.6 20 1997/10/23(97.81) 12:28:32.3 27.00 100.38 5.5 2 1986 1998 20 1
34 1986 1998 33 3 (1) 32 100.49 25.336 3 3 1986 1998 3 1986 1998 2 2 1986 1998 ( ) ( ) ( 99%) ( ) ( ) 0.977 24 1.203 20 0.005 95 0.017 09 ( 0.023 57 0.034 31) 0.977 24 ( 99%) 50.27 40 1986 1998 3 4 ( 0.15 a) 1 2 4 5 6 9 10 11 12 13 14 16 17 18 19 5 3 7 8 15 20 75% (12 a 32 )
34 2013 4 1986 1998 (a) 1 6 (b) 7 9 11 12 (c) 10, 13 (d) 14 20
34 1986 1998 35 5 [9] 5 1986 1998 ( 11 1991/4/11 (91.28)) ( 16 91.25) (0.05 a) ( 2 1987/05/18 (87.38)) ( 6 87.25 7 87.67) 5 4 1) s = 0.017 09 0.5 0.6 4 5 90 50.27 40 2) 4 5 3) [9]
36 2013 [11] [1],.. :, 1991 [2],,.. :, 1985 [3] Kimura C. Bull Geod ANNEE, 1925, 535 [4] 1978 21(4): 278 [5] Barlik M, Rogowski J B. Prace Nauk Politech Warsz, 1989, 33: 19 [6] 2005, 25(1): 58 [7],., 2008, 23(6): 1736 [8],,., 2001, 23(1): 61 [9],. D :, 2008, 38(4): 432 [10],., 2005, 46(4): 460 [11] Chen Y T, Gu H D, Lu Z X. Physics of Earth and Planetary Interior, 1979, 18(4): 330 Plumb Line Variation at Midu During 1986 1998 and Its Relation with the Earthquakes Around Yang Yong-zhang 1,2,3, Ping Jin-song 1,3, Li Zheng-xin 2,3, Li Hui 4 (1. University of Chinese Academy of Sciences Beijing 100049; 2. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030; 3. National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012; 4. Institute of Seismology, China Seismological Bureau, Wuhan 430071) Abstract: Plumb line variations (PLV) at Midu during the years of 1986 1998 are determined by using the 32 batch repeated gravity observations of the West-Yunan network. It has been found that PLV at Midu are related with the 20 earthquakes in this period. It appears that the time of an earthquake around Midu is usually quite the same when PLV at Midu begins moving in opposite direction. Key words: plumb line variations; West-Yunnan network; earthquake