Body Wave Magnitude
MB = log (A/T) +Q(D,h)
T, the period in seconds, is restricted to 0.1 <= T <= 3.0
A, the ground amplitude in micrometers
Q is a function of distance (D) and depth (h)
D is the distance in geocentric degrees (station to epicenter), 5 <= D <= 109
No depth corrections are applied, and Ms magnitudes are not generally computed for depths greater than 50 kilometers.
Magnitude mb Magnitude mb
5 6 7 8 5 6 7 8
Distance (degrees) Q for h=15 km Ground Motion Amplitude (microns) for T = 1 s Log of Ground Motion Amplitude (microns) for T = 1 s
20 6.1 0.079433 0.794328 7.943282 79.43282 -1.1 -0.1 0.9 1.9
30 6.6 0.025119 0.251189 2.511886 25.11886 -1.6 -0.6 0.4 1.4
40 6.46 0.034674 0.346737 3.467369 34.67369 -1.46 -0.46 0.54 1.54
50 6.76 0.017378 0.17378 1.737801 17.37801 -1.76 -0.76 0.24 1.24
60 6.9 0.012589 0.125893 1.258925 12.58925 -1.9 -0.9 0.1 1.1
70 6.9 0.012589 0.125893 1.258925 12.58925 -1.9 -0.9 0.1 1.1
80 6.76 0.017378 0.17378 1.737801 17.37801 -1.76 -0.76 0.24 1.24
90 7 0.01 0.1 1 10 -2 -1 0 1
100 7.3 0.005012 0.050119 0.501187 5.011872 -2.3 -1.3 -0.3 0.7
Magnitude mb Magnitude mb
5 6 7 8 5 6 7 8
Distance (degrees) Q for h=15 km Ground Motion Velocity (microns/s) for T = 1 s Log of Ground Motion Velocity (microns/s) for T = 1 s
20 6.1 0.498838 4.988381 49.88381 498.8381 -0.30204 0.69796 1.69796 2.69796
30 6.6 0.157746 1.577465 15.77465 157.7465 -0.80204 0.19796 1.19796 2.19796
40 6.46 0.217751 2.177507 21.77507 217.7507 -0.66204 0.33796 1.33796 2.33796
50 6.76 0.109134 1.091339 10.91339 109.1339 -0.96204 0.03796 1.03796 2.03796
60 6.9 0.079061 0.790605 7.906052 79.06052 -1.10204 -0.10204 0.89796 1.89796
70 6.9 0.079061 0.790605 7.906052 79.06052 -1.10204 -0.10204 0.89796 1.89796
80 6.76 0.109134 1.091339 10.91339 109.1339 -0.96204 0.03796 1.03796 2.03796
90 7 0.0628 0.628 6.28 62.8 -1.20204 -0.20204 0.79796 1.79796
100 7.3 0.031475 0.314746 3.147456 31.47456 -1.50204 -0.50204 0.49796 1.49796
Q Table Used within NEIC Programs (See also: http://www.seismo.com/msop/msop79/par/par.html#aa200)
Delta (deg) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Depth (km) 0 25 50 75 100 150 200 250 300 350 400 450 500 550 600 650 700
1 5.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2 5.8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
3 6.1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
4 6.4 6.3 6 6 6 6 5.9 5.7 5.6 5.7 5.7 5.8 5.8 5.8 5.7 5.7 5.7
5 6.5 6.5 6.2 6.1 6 6 6 5.7 5.7 5.7 5.8 5.9 5.8 5.8 5.8 5.7 5.7
6 7 6.8 6.5 6.4 6.3 6.2 6 5.8 5.7 5.8 5.9 5.9 5.9 5.9 5.8 5.7 5.7
7 7 7 6.6 6.5 6.4 6.4 6 5.8 5.8 5.9 6 6.1 6 5.9 5.8 5.8 5.7
8 7.2 7 6.8 6.6 6.6 6.4 6.1 5.8 5.8 6 6.1 6.1 6.1 6 5.9 5.8 5.7
9 7.3 7.1 6.9 6.8 6.7 6.4 6.1 5.9 5.9 6.1 6.2 6.2 6.2 6.1 5.8 5.8 5.7
10 7.2 7 6.9 6.7 6.6 6.4 6.2 5.9 6 6.2 6.2 6.2 6.2 6.1 5.9 5.8 5.8
11 7.1 7 6.8 6.7 6.5 6.3 6.2 6 6 6.2 6.2 6.2 6.2 6.2 6 5.8 5.8
12 7 6.9 6.7 6.5 6.4 6.2 6.2 6 6.1 6.2 6.2 6.2 6.3 6.2 6 5.9 5.8
13 6.6 6.5 6.5 6.1 6 6.1 6.2 6.1 6.1 6.2 6.2 6.3 6.3 6.2 6.1 5.9 5.8
14 6.3 6.1 6 6 6 6.1 6.2 6.2 6.1 6.1 6.2 6.3 6.4 6.3 6.1 5.9 5.8
15 5.9 5.9 5.9 5.9 6 6.1 6.2 6.2 6.2 6.1 6.2 6.3 6.4 6.3 6.2 6 5.9
16 5.9 5.9 5.9 6 6 6.1 6.2 6.2 6.2 6.1 6.1 6.3 6.4 6.4 6.2 6.1 5.9
17 5.9 5.9 5.9 6 6 6.1 6.2 6.3 6.2 6.1 6.1 6.3 6.4 6.4 6.3 6.1 6
18 6 6 6 6 6.1 6.1 6.3 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.3 6.1 6
19 6.1 6.1 6.1 6.1 6.1 6.2 6.3 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.2 6
20 6.1 6.2 6.1 6.1 6.1 6.2 6.3 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.2 6
21 6.2 6.2 6.2 6.2 6.1 6.2 6.3 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.3 6.1
22 6.3 6.3 6.2 6.2 6.1 6.2 6.4 6.3 6.2 6.1 6.2 6.3 6.4 6.4 6.4 6.3 6.1
23 6.4 6.3 6.3 6.2 6.2 6.3 6.4 6.3 6.2 6.1 6.2 6.3 6.3 6.4 6.4 6.4 6.1
24 6.5 6.4 6.3 6.2 6.2 6.3 6.4 6.3 6.2 6.1 6.2 6.3 6.3 6.4 6.4 6.4 6.2
25 6.5 6.4 6.3 6.3 6.3 6.4 6.5 6.4 6.2 6.1 6.2 6.2 6.3 6.4 6.4 6.4 6.2
26 6.5 6.4 6.4 6.3 6.3 6.4 6.5 6.4 6.2 6.1 6.2 6.2 6.3 6.4 6.4 6.4 6.3
27 6.6 6.5 6.4 6.4 6.4 6.5 6.5 6.4 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.3
28 6.6 6.5 6.4 6.4 6.4 6.5 6.5 6.4 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.3
29 6.6 6.6 6.5 6.5 6.5 6.5 6.5 6.4 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.3
30 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.3
31 6.7 6.7 6.6 6.6 6.5 6.6 6.4 6.4 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.4
32 6.7 6.7 6.6 6.6 6.6 6.5 6.4 6.4 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.4
33 6.7 6.7 6.7 6.7 6.6 6.5 6.4 6.4 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.4 6.3
34 6.6 6.7 6.7 6.7 6.7 6.5 6.4 6.3 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.3 6.3
35 6.6 6.7 6.7 6.7 6.7 6.5 6.4 6.3 6.3 6.1 6.1 6.2 6.3 6.4 6.4 6.3 6.3
36 6.5 6.6 6.7 6.7 6.7 6.5 6.4 6.3 6.2 6.1 6.1 6.2 6.3 6.4 6.4 6.3 6.3
37 6.5 6.6 6.7 6.7 6.7 6.5 6.4 6.3 6.2 6.1 6.1 6.2 6.3 6.4 6.3 6.3 6.3
38 6.4 6.5 6.6 6.7 6.6 6.5 6.4 6.3 6.1 6 6.1 6.2 6.3 6.4 6.3 6.3 6.3
39 6.4 6.5 6.6 6.7 6.6 6.5 6.3 6.2 6.1 6 6.1 6.2 6.3 6.4 6.3 6.2 6.3
40 6.5 6.5 6.5 6.6 6.6 6.4 6.3 6.2 6 6 6.1 6.2 6.3 6.3 6.3 6.2 6.3
41 6.5 6.5 6.5 6.6 6.6 6.4 6.3 6.2 6 6 6.1 6.2 6.3 6.3 6.3 6.2 6.3
42 6.5 6.5 6.5 6.6 6.6 6.4 6.3 6.1 6 6 6.1 6.2 6.3 6.3 6.3 6.2 6.3
43 6.6 6.6 6.5 6.6 6.6 6.4 6.3 6.1 6.1 6 6.1 6.2 6.3 6.3 6.3 6.2 6.2
44 6.7 6.7 6.6 6.6 6.6 6.4 6.2 6.1 6.1 6 6.1 6.2 6.3 6.3 6.3 6.2 6.2
45 6.8 6.7 6.7 6.7 6.6 6.4 6.2 6.1 6.1 6 6.1 6.2 6.3 6.3 6.3 6.2 6.2
46 6.9 6.8 6.7 6.7 6.6 6.4 6.2 6.1 6.1 6 6.1 6.2 6.3 6.3 6.3 6.2 6.2
47 6.9 6.8 6.8 6.7 6.6 6.5 6.2 6.1 6.1 6 6.1 6.2 6.2 6.3 6.3 6.2 6.2
48 6.8 6.8 6.8 6.8 6.7 6.5 6.2 6.2 6.1 6.1 6.1 6.2 6.2 6.3 6.3 6.2 6.2
49 6.7 6.8 6.8 6.8 6.8 6.5 6.3 6.2 6.1 6.1 6.1 6.1 6.2 6.3 6.3 6.1 6.1
50 6.7 6.7 6.8 6.8 6.8 6.5 6.3 6.2 6.2 6.1 6.1 6.1 6.2 6.2 6.2 6.1 6.1
51 6.7 6.7 6.8 6.8 6.8 6.5 6.4 6.2 6.2 6.1 6.1 6.1 6.1 6.2 6.2 6.1 6.1
52 6.7 6.7 6.8 6.8 6.8 6.6 6.4 6.2 6.2 6.1 6.1 6.1 6.1 6.1 6.2 6.1 6.1
53 6.8 6.8 6.8 6.8 6.8 6.6 6.4 6.3 6.2 6.1 6.1 6.1 6.1 6.1 6.1 6.1 6
54 6.8 6.8 6.8 6.8 6.8 6.6 6.5 6.3 6.2 6.2 6.1 6.1 6.1 6.1 6.1 6 6
55 6.8 6.8 6.8 6.8 6.8 6.7 6.5 6.3 6.2 6.2 6.1 6.1 6.1 6.1 6.1 6 6
56 6.8 6.8 6.8 6.9 6.8 6.7 6.5 6.4 6.2 6.2 6.2 6.2 6.1 6.1 6 6 6
57 6.8 6.8 6.9 6.9 6.8 6.7 6.5 6.4 6.3 6.2 6.2 6.2 6.1 6.1 6 6 6
58 6.9 6.9 6.9 6.9 6.9 6.7 6.5 6.4 6.3 6.2 6.2 6.2 6.2 6.1 6 6 6
59 6.9 6.9 6.9 6.9 6.9 6.7 6.5 6.4 6.3 6.3 6.2 6.2 6.2 6.1 6 6 6
60 6.9 6.9 6.9 6.9 6.8 6.7 6.5 6.4 6.3 6.3 6.3 6.3 6.2 6.2 6.1 6 6
61 7 6.9 6.9 6.9 6.8 6.7 6.6 6.4 6.4 6.3 6.3 6.3 6.3 6.2 6.1 6.1 6
62 7 6.9 6.9 6.8 6.7 6.7 6.6 6.5 6.4 6.4 6.4 6.3 6.3 6.2 6.2 6.1 6
63 7 6.9 6.8 6.7 6.7 6.7 6.6 6.5 6.5 6.4 6.4 6.4 6.4 6.3 6.2 6.1 6.1
64 7 6.9 6.8 6.7 6.7 6.7 6.6 6.5 6.5 6.5 6.4 6.4 6.4 6.3 6.2 6.1 6.1
65 7 6.9 6.8 6.7 6.7 6.7 6.5 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.2 6.2 6.1
66 7 6.9 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.3 6.2 6.1
67 7 6.9 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.3 6.2 6.2
68 7 6.9 6.7 6.7 6.6 6.6 6.5 6.5 6.5 6.5 6.4 6.4 6.4 6.3 6.3 6.2 6.2
69 6.9 6.9 6.7 6.7 6.6 6.6 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.3 6.3 6.2 6.2
70 6.9 6.9 6.7 6.7 6.6 6.6 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.3 6.3 6.3 6.2
71 6.9 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.3 6.3 6.3 6.2
72 6.9 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.3 6.3 6.3 6.3
73 6.8 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4 6.4 6.3 6.3 6.3 6.3 6.3
74 6.8 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.5 6.4 6.3 6.2 6.3 6.3 6.3
75 6.9 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.5 6.4 6.3 6.2 6.3 6.3 6.3
76 6.9 6.8 6.8 6.7 6.6 6.5 6.5 6.5 6.5 6.6 6.5 6.4 6.2 6.2 6.2 6.3 6.3
77 6.9 6.8 6.8 6.7 6.6 6.5 6.5 6.5 6.5 6.6 6.5 6.4 6.2 6.2 6.2 6.3 6.3
78 6.8 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.6 6.6 6.5 6.4 6.2 6.2 6.2 6.3 6.3
79 6.7 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.6 6.6 6.5 6.4 6.2 6.2 6.2 6.3 6.3
80 6.8 6.8 6.7 6.7 6.6 6.5 6.5 6.5 6.6 6.6 6.5 6.4 6.3 6.3 6.3 6.3 6.3
81 6.9 6.8 6.8 6.7 6.6 6.5 6.5 6.5 6.6 6.6 6.5 6.4 6.3 6.3 6.3 6.3 6.3
82 7 6.9 6.8 6.7 6.7 6.6 6.5 6.5 6.6 6.6 6.5 6.5 6.3 6.3 6.3 6.4 6.3
83 7 7 6.8 6.8 6.7 6.6 6.5 6.6 6.6 6.6 6.5 6.5 6.4 6.4 6.4 6.4 6.3
84 7 7 6.9 6.8 6.7 6.6 6.5 6.6 6.6 6.6 6.6 6.5 6.4 6.4 6.4 6.4 6.4
85 6.9 7 7 6.8 6.8 6.6 6.6 6.6 6.6 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4
86 7 7 7 6.9 6.8 6.7 6.6 6.6 6.7 6.7 6.6 6.5 6.5 6.5 6.5 6.5 6.4
87 7.1 7.1 7 6.9 6.8 6.8 6.6 6.6 6.7 6.7 6.6 6.6 6.6 6.6 6.6 6.5 6.4
88 7 7.1 7.1 7 6.9 6.8 6.7 6.7 6.7 6.7 6.6 6.6 6.6 6.7 6.7 6.6 6.5
89 7 7 7.1 7 6.9 6.8 6.7 6.7 6.7 6.7 6.6 6.7 6.7 6.7 6.7 6.7 6.5
90 7.1 7.1 7.2 7.1 7 6.9 6.8 6.7 6.7 6.7 6.7 6.7 6.7 6.8 6.8 6.7 6.6
91 7.1 7.2 7.2 7.2 7.1 6.9 6.8 6.8 6.7 6.8 6.7 6.8 6.8 6.8 6.8 6.8 6.7
92 7.2 7.2 7.2 7.2 7.1 7 6.9 6.8 6.8 6.8 6.8 6.8 6.8 6.9 6.8 6.9 6.7
93 7.1 7.2 7.2 7.2 7.2 7 6.9 6.9 6.9 6.9 6.9 6.9 6.9 6.9 7 6.9 6.8
94 7.2 7.2 7.2 7.2 7.2 7.1 7 7 6.9 6.9 6.9 6.9 6.9 7 7 7 6.9
95 7.3 7.2 7.3 7.3 7.3 7.2 7.1 7 7 7 6.9 7 7 7 7 7 6.9
96 7.4 7.3 7.3 7.3 7.3 7.2 7.1 7.1 7 7 7 7 7.1 7.1 7.1 7 7
97 7.5 7.3 7.3 7.3 7.3 7.3 7.2 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7
98 7.5 7.3 7.3 7.3 7.4 7.3 7.2 7.2 7.2 7.1 7.1 7.2 7.2 7.2 7.2 7.1 7
99 7.3 7.3 7.3 7.4 7.4 7.3 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.1
100 7.4 7.3 7.4 7.4 7.4 7.4 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.2 7.1
101 7.4 7.4 7.4 7.5 7.5 7.5 7.4 7.3 7.3 7.3 7.4 7.4 7.4 7.4 7.3 7.3 7.2
102 7.5 7.5 7.5 7.5 7.6 7.6 7.5 7.4 7.4 7.4 7.5 7.5 7.5 7.5 7.4 7.3 7.2
103 7.6 7.6 7.6 7.7 7.7 7.7 7.7 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.5 7.4 7.3
104 7.7 7.7 7.7 7.8 7.8 7.8 7.8 7.8 7.8 7.8 7.7 7.7 7.7 7.6 7.6 7.5 7.4
105 7.8 7.8 7.8 7.8 7.8 7.9 7.9 7.9 7.9 7.9 7.8 7.8 7.7 7.7 7.6 7.5 7.4
106 7.8 7.8 7.9 7.9 7.9 7.9 7.9 8 8 8 7.9 7.8 7.7 7.7 7.6 7.5 7.4
107 7.9 7.9 7.9 7.9 7.9 8 8 8 8 8 8 7.8 7.8 7.7 7.7 7.6 7.5
108 8 8 8 8 8 8 8 8 8 8 8 7.9 7.8 7.7 7.7 7.6 7.5