Table 1 Parameters and computed frequency fields of nine Ms ≥7.0 earthquakes in mainland China
No.
|
Date
|
Location
|
Magnitude (Ms)
|
Coordinates of the study area (latitude and longitude)
|
Time span of the data
|
Range of seismic magnitudes (ML)
|
First four eigenvalues
|
Accuracy, r
|
1
|
1985-8-23
|
Wuqia(Xinjiang)
|
7.1
|
39.0°–41.5°,
74.5°–77.5°
|
1975-01–1985-07
|
2.8–5.4
|
3.5912×103
0.9524×103
0.6985×103
0.6403×103
|
0.8329
|
2
|
1988-11-6
|
Lancang-Genma(Yunnan)
|
7.6
|
21.5°–23.5°, 99.0°–101.0°
|
1975-01–1988-10
|
2.7–5.4
|
235.8914
155.9525
136.1460
99.0805
|
0.6800
|
3
|
1990-4-26
|
Gonghe(Qinghai)
|
7.0
|
34.0°–37.0°, 98.5°–101.5°
|
1980-01–1990-03
|
2.8–5.4
|
91.0688
58.5975
40.8794
15.9304
|
0.9227
|
4
|
1990-6-14
|
Jimunai (Xinjiang)
|
7.2
|
46.0°–49.0°, 83.5°–86.5°
|
1980-01–1990-05
|
3.0–5.4
|
13.1051
10.3549
3.6816
1.5037
|
0.8021
|
5
|
1995-7-12
|
China-Myanmar borderr
|
7.3
|
21.0°–24.0°,
98.5°–102.0°
|
1985-01–1995-06
|
3.0–5.4
|
1.0670×103
0.5072×103
0.2105×103
0.1965×103
|
0.8107
|
6
|
1996-2-3
|
Lijiang(Yunnan)
|
7.0
|
26.5°–29.0°,
98.4°–100.9°
|
1985-01–1996-01
|
2.8–5.4
|
41.3727
16.8231
12.9331
6.0894
|
0.7857
|
7
|
2008-5-12
|
Wenchuan(Sichuan)
|
8.0
|
30.0°–33.5°,
101.5°–106°
|
1995-01–2008-04
|
2.7–5.4
|
647.9299
213.4451
157.4164
96.7784
|
0.8585
|
8
|
2010-4-14
|
Yushu(Qinghai)
|
7.1
|
32.0°–34.5°,
95.5°–98.5°
|
1995-01–2010-04
|
3.0–5.4
|
635.2714
101.7391
88.7516
71.5995
|
0.9290
|
9
|
2013-4-20
|
Lushan( Sichuan)
|
7.0
|
29.5°–31.5°,
102.5°–105.5°
|
2000-01–2013-03
|
2.7–5.4
|
298.9720
259.1229
33.7822
26.0381
|
0.9178
|
10
|
2017-8-8
|
Jiuzhaigou(Sichuan)
|
7.0
|
32.0°–34.0°,
103.0°–105.0°
|
2000-01–2017-07
|
2.7–5.4
|
661.8619
391.0843
176.3636
102.7762
|
0.7898
|
Note: The earthquake time in the table is Beijing time in China.
Table 2 Parameters of the strain field temporal factors of ten Ms≥7.0 earthquakes in mainland China
No.
|
Earthquake
|
Temporal factor
|
Time of anomaly (year-month)
|
Maximum abnormal amplitude
|
Mean square error
|
Proportion of anomalous strain fields in all fields
|
1
|
1985-8-23 Wuqia(Xinjiang), Ms 7.1
|
1
|
1983-02–04
|
-38.7708
|
5.3815
|
0.5085
|
2
|
1982-12–1983-02
|
4.8120
|
2.7715
|
0.1349
|
3
|
1983-04–06
|
-12.1061
|
2.3735
|
0.0989
|
4
|
1983-06–08
|
6.9730
|
2.2724
|
0.0907
|
2
|
1988-11-6 Lancang-Gengma (Yunnan) ,Ms 7.6
|
1
|
1987-10–1988-10
|
-5.9957∨
|
1.2030
|
0.2558
|
2
|
1988-07–10
|
6.6598∨
|
0.9781
|
0.1691
|
3
|
1988-08–10
|
-1.1282
|
0.9139
|
0.1476
|
4
|
1987-09–11
|
-5.6940
|
0.7797
|
0.1074
|
3
|
1990-4-26 Gonghe( Qinghai), Ms 7.0
|
1
|
1987-08–1988-04
|
-3.8884
|
0.8712
|
0.4070
|
2
|
1987-09–1988-06
|
3.5326
|
0.6988
|
0.2618
|
3
|
1989-04–06
|
-3.6195
|
0.5837
|
0.1827
|
4
|
1987-03–05
|
2.0295
|
0.3644
|
0.0712
|
4
|
1990-6-14 Jimunai(Xinjiang),Ms 7.2
|
1
|
1989-09–11
|
1.9896
|
0.3277
|
0.3670
|
2
|
1989-07–09
|
1.9925
|
0.2913
|
0.2900
|
3
|
1990-02–04
|
1.0846∨
|
1.0846
|
0.1031
|
4
|
×
|
×
|
×
|
×
|
5
|
1995-6-14 China–Myanmar border, Ms 7.3
|
1
|
1995-02–04
|
17.4633∨
|
2.9453
|
0.4366
|
2
|
1993-04–06
|
-11.5929
|
2.0308
|
0.2076
|
3
|
1993-11–1994-10
|
-7.4821∨
|
1.3083
|
0.0861
|
4
|
1993-09–1994-11
|
-6.8692
|
1.2641
|
0.0804
|
6
|
1996-2-3 Lijiang(Yunnan) , Ms 7.0
|
1
|
1993-03–05
|
3.6293
|
0.5641
|
0.4210
|
2
|
1993-01–1995-06
|
1.4570
|
0.3597
|
0.1712
|
3
|
1993-01–1994-02
|
1.3167
|
0.3154
|
0.1316
|
4
|
1992-11–1993-02
|
0.5076
|
0.2164
|
0.0620
|
7
|
2008-5-12 Wenchuan(Sichuan), Ms 8.0
|
1
|
2006-05–07
|
-14.1671
|
2.0315
|
0.4986
|
2
|
2005-01–2007-01
|
-8.6209
|
1.1660
|
0.1643
|
3
|
2008-02–04
|
6.4793∨
|
1.0013
|
0.1211
|
4
|
2007-04–06
|
1.5711
|
0.7851
|
0.0745
|
8
|
2010-4-14 Yushu(Qinghai), Ms 7.1
|
1
|
2006-05–07
|
-14.4247
|
1.8734
|
0.6577
|
2
|
2010-02–04
|
9.7744∨
|
0.7497
|
0.1052
|
3
|
2010-01–03
|
1.3678
|
0.7002
|
0.0919
|
4
|
2010-01–03
|
0.4226
|
0.6289
|
0.0741
|
9
|
2013-4-20 Lushan(Sichuan), Ms 7.0
|
1
|
2013-02–03
|
11.7708∨
|
1.3844
|
0.4441
|
2
|
2012-01–03
|
-7.6751
|
1.2888
|
0.3849
|
3
|
2012-10–12
|
-3.1351∨
|
0.4654
|
0.0502
|
4
|
2012-02–09
|
2.0213
|
0.4085
|
0.0387
|
10
|
2017-8-8 Jiuzhaigou(Sichuan), Ms 7.0
|
1
|
2006-04–06
|
-1.4225
|
1.7266
|
0.3906
|
2
|
2015-10–12
|
-2.5068
|
0.4107
|
0.1766
|
3
|
2013-05–11
|
-2.5522
|
0.3883
|
0.1579
|
4
|
2005-05–2006-04
|
-0.5682
|
0.2222
|
0.0647
|
Note: “∨” means there is a short-term abnormality, “×” means no abnormality or the abnormality is not obvious.
Table 3 Distribution of seismic activity anomalies in the study area before Ms ≥7.0 earthquakes strain field
No.
|
Earthquake
|
Fore-shock/
(y-m-d)
|
Epicentre/
(°N,°E)
|
Magnitude/(ML)
|
Location
|
time factor
|
Grid
|
Distance from main shock/
(km)
|
1
|
1985 Wuqia( Xinjiang), Ms7.1
|
1983-06-05
|
39.20,75.50
|
5.4
|
Shufu
|
3、4
|
6
|
43#
|
1983-03-30
|
40.10,75.50
|
5.4
|
Wuqia
|
1
|
8
|
63
|
1985-06-29
|
39.20,75.50
|
4.5
|
Shufu
|
2、4
|
6
|
41√
|
2
|
1988 Lancang-Gengma(Yunnan), Ms 7.6
|
1987-09-3
|
22.42,99.37
|
4.8
|
Menglian
|
1、4
|
2
|
58
|
1988-03-04
|
22.42,99.87
|
4.5
|
Lancang
|
1
|
6
|
47#
|
1988-08-15
|
22.83,99.72
|
5.0
|
Lancang
|
1、2、3
|
7
|
0√
|
3
|
1990
Gonghe(Qinghai), Ms 7.0
|
1988-01-19
|
35.42,99.27
|
4.5
|
Xinghai
|
1、2
|
9
|
110#
|
1988-06-09
|
35.50,99.53
|
4.8
|
Xinhai
|
2
|
15
|
89
|
1987-04-30
|
34.25,100.33
|
4.1、4.0
|
Maqin
|
4
|
19
|
210
|
1989-06-16
|
34.67,101.18
|
4.7
|
Henan
|
3
|
32
|
188
|
4
|
1990 Jjimuna(Xinjiang), Ms 7.2
|
1989-07-04
|
47.50,85.42
|
3.9
|
Jimunai
|
2
|
21
|
52
|
1989-08-14
|
46.83,86.27
|
4.3
|
Bukesai
|
2
|
32
|
148
|
1990-02-28
|
46.38,83.77
|
4.0
|
E’Min
|
3
|
1
|
193
|
1989-11-11
|
48.02,85.78
|
4.3
|
Habahe
|
1
|
29
|
54
|
5
|
1995 China–Myanmar border, Ms 7.3
|
1993-06-04
|
23.67,100.42
|
5.4
|
Jinggu
|
2
|
24
|
215#
|
1994-09-24
|
22.40,98.82
|
5.1
|
Menglian
|
2、3、4
|
3
|
62#
|
1995-07-4
|
22.33,99.07
|
4.6
|
Menglian
|
1
|
9
|
38√
|
1995-02-18
|
22.98,99.68
|
5.4
|
Lancang
|
1
|
16
|
116
|
6
|
1996
Lijiang(Yunnan), Ms 7.0
|
1993-05-11
|
28.05,99.68
|
4.5
|
Zhongdian
|
1、2、3
|
13
|
90#
|
1992-12-04
|
27.68,99.93
|
4.2
|
Zhongdian
|
4
|
18
|
53
|
1994-07-16
|
26.83,100.23
|
3.6
|
Lijiang
|
2、3
|
16
|
52
|
1995-04-27
|
27.13,100.83
|
3.8
|
Ninglang
|
2
|
22
|
63
|
7
|
2008
Wenchuan(Sichuan), Ms 8.0
|
2004-12-15
|
32.30,101.60
|
4.3
|
Maer’kang
|
2
|
5
|
210
|
2005-01-05
|
32.30,101.60
|
5.0
|
Maer’kang
|
2
|
5
|
210#
|
2006-06-21
|
33.10,104.90
|
5.4
|
Wenxian
|
1、3
|
49
|
253
|
2008-02-27
|
30.10,101.90
|
5.0
|
Kangding
|
3
|
1
|
190√
|
8
|
2010 Yushu(Qinghai), Ms 7.1
|
2006-07-18
|
33.07,96.29
|
5.4
|
Yushu
|
1
|
8
|
33
|
2010-04-14
|
33.12,96.58
|
5.2
|
Yushu
|
2、3、4
|
13
|
11√
|
9
|
2013 Lushan(Sichuan), Ms 7.0
|
2012-10-19
|
30.1,102.8
|
4.6
|
Tianquan
|
2、3、4
|
2
|
24
|
2013-02-19
|
31.2,105.2
|
5.3
|
Santai
|
2、3
|
24
|
234√
|
2013-03-04
|
31.0,103.4
|
4.1
|
Wenchuan
|
1、2、3
|
7
|
86√*
|
2013-04-08
|
30.8,103.3
|
4.2
|
Chongqing
|
1、2、3、4
|
12
|
63√*
|
10
|
2017 Jiuzhaigou(Sichuan), Ms 7.0
|
2014-03-13
|
33.15,103.78
|
4.2
|
Jiuzhaigou
|
1
|
7
|
5
|
2015-10-19
|
32.42,104.97
|
4.2
|
Qingchuan
|
2、3
|
13
|
146*
|
2013-07-27
|
33.00,104.90
|
4.9
|
Wenxian
|
3
|
14
|
110
|
Note: “√” means short-term foreshocks; “*” means controversial foreshocks, some are considered to be aftershocks of the Wenchuan 8.0 earthquake, others are considered to be the foreshocks of Lushan; “#” indicates the earthquake group.
Table 4 Comparison of fitting accuracy between energy field and strain field
Earthquake
|
2008 Wenchuan, Sichuan Ms 8.0
|
1988 Lancang-Gengm, Yunnan Ms7.6
|
1990 Gonghe, Qinghai Ms7.0
|
The first four typical field fitting accuracy of the energy field method
|
0.9996
|
0.9865
|
0.9997
|
Four typical field fitting accuracy of strain field method
|
0.9020
|
0.6800
|
0.9227
|