5/8/26
Nevada Test Site seismicity from January 27 to February 2, 2026 recovered using waveform cross correlation and IMS data
The week from jan 27 to Feb 2, 2026 is charaterized by a slighly higher seismicity than the previous 7 days. There were 36 events detected by waveform cross correlation (WCC) applied to seismic data of the International Monitoring System. Figur below shows their locations realtive to the NTS geographical center and 27 master events selected from the Reviwed Event Bulletin of the International Data Centre.
There is also an extended version of the WCC with an effective ambient noise suppression based on addition of stochastic noise. It takes more time to calculate and the result is coming soon. The extended method is focused on the central part of the NTS where the tests were conducted.
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Figure. Locations of master events (red) and the events found by cross correlation (green). The NST center is shown by black circle.
5/7/26
Nevada Test Site seismicity from January 22 to January 26, 2026 recovered using waveform cross correlation
This post follows teh same structure as the previous few on the Nevada Test Site seismic activity. Five days are presented. Figure below shows locations of 25 events found by waveform cross correlation. Catalog is below.
Figure. Locations of master events (red) and the events found by cross correlation (yellow). The NST center is shown by black circle.
5/2/26
Nevada Test Site seismicity on January 21, 2026 recovered using waveform cross correlation
Following my previous posts on the recovery of seismic events at the Nevada Test Site on June 22, 2020 and around, it's to continue to trace the evolution of seismic regime at the NTS. Started with January 20, 2026 and we continue here with Jan 21. Figure below shows the locations of 27 master events and 9 events found by cross correlation. The corresponding bulletin (XSEL) is given below. (For details please see the previous post)
Figure. Locations of master events (red) and the events found by cross correlation (yellow). The NST center is shown by black circle.
# MASTER hh:mm:ss ot_stdev Lat Lon Depth Mb mb_stdev ndef NEW ORID SeisReg Ndef(SEL)
1 24060380 3:59: 30.28 1.47 36.761 -117.789 0.0 2.19 0.89 3 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.32 166.12 4: 0: 2.25 -0.626 32.67 25.15 5.4 2.8 -99.0 -3.121 0.110 10.00 3 -99.00
ELK 3.94 -152.66 4: 0: 41.80 1.969 69.32 62.30 3.9 2.2 -99.0 -1.700 0.014 9.00 2 -99.00
PDAR 8.26 230.76 4: 1: 38.33 -1.477 129.61 124.26 3.3 2.5 -99.0 -0.980 0.040 9.00 2 -99.00
2 10374180 4:15: 14.56 0.06 37.654 -115.255 0.0 2.02 0.76 3 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.60 106.97 4:15: 56.09 0.061 41.53 42.61 5.9 3.1 -99.0 -1.915 0.104 10.00 2 -99.00
ELK 3.04 -179.76 4:16: 4.00 0.021 49.50 48.86 11.5 3.1 -99.0 -1.713 0.086 9.00 2 -99.00
PDAR 6.62 221.99 4:16: 56.24 -0.082 101.89 100.59 4.8 2.8 -99.0 -0.222 0.042 9.00 4 -99.00
3 10374180 6:18: 22.81 1.22 37.890 -115.855 0.0 2.17 0.72 4 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.60 104.89 6:18: 53.95 -0.070 31.30 42.61 4.6 3.3 -99.0 -2.173 0.061 10.00 2 -99.00
ELK 3.04 -170.33 6:19: 10.43 0.734 46.79 48.86 3.4 2.8 -99.0 -1.377 0.034 9.00 1 -99.00
PDAR 6.62 221.99 6:20: 4.32 -1.896 103.63 100.59 3.8 3.3 -99.0 -0.713 0.079 9.00 3 -99.00
ILAR 32.94 129.85 6:24: 55.35 1.355 391.24 394.79 3.8 4.4 -99.0 -0.276 0.187 8.00 2 -99.00
4 24060380 8:28: 36.06 0.87 37.200 -117.294 0.0 4.14 0.29 5 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.32 146.73 8:29: 4.24 0.332 27.90 25.15 4.6 5.4 -99.0 -3.637 0.085 10.00 3 -99.00
ANMO 9.28 287.52 8:30: 50.70 0.224 134.45 137.52 3.6 4.6 -99.0 0.452 0.570 8.50 1 -99.00
ULM 20.27 238.38 8:33: 13.74 1.324 276.30 277.57 3.4 3.2 -99.0 -0.126 0.198 7.50 2 -99.00
YKA 25.34 185.53 8:34: 3.02 -1.096 328.09 327.80 3.5 3.3 -99.0 -0.323 0.075 8.00 4 -99.00
BVAR 89.83 6.34 8:41: 37.19 -0.840 781.96 781.67 4.3 6.9 -99.0 0.074 0.125 7.00 4 -99.00
5 11690187 8:31: 19.21 0.70 37.454 -117.159 0.0 3.88 0.46 5 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.53 136.87 8:31: 42.45 -0.686 23.98 27.82 6.6 292.5 -99.0 -2.295 0.095 10.00 3 -99.00
YBH 6.23 135.55 8:32: 52.81 1.266 92.12 94.62 3.5 3.4 -99.0 -0.994 0.292 8.30 3 -99.00
PDAR 8.15 228.98 8:33: 18.52 0.194 119.01 122.45 4.0 15.5 -99.0 -0.626 0.108 9.00 3 -99.00
YKA 25.43 184.93 8:36: 45.18 -0.411 326.31 329.17 3.8 4.8 -99.0 -0.874 0.158 8.00 3 -99.00
USRK 77.64 49.90 8:43: 15.41 -0.440 716.69 717.67 3.5 6.5 -99.0 0.195 0.178 5.50 4 -99.00
6 7564944 14: 4: 8.07 0.06 38.729 -116.120 0.0 1.27 0.85 3 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.49 79.36 14: 4: 40.70 0.043 32.65 28.03 6.7 6.8 -99.0 -2.572 0.060 10.00 2 -99.00
ELK 2.64 -161.14 14: 4: 48.12 -0.082 40.08 49.80 3.8 2.8 -99.0 -1.149 0.009 9.00 1 -99.00
PDAR 6.89 231.57 14: 6: 4.91 0.050 116.77 125.28 3.3 3.5 -99.0 -0.531 0.056 9.00 3 -99.00
7 19344894 22:38: 38.44 1.33 36.656 -117.175 0.0 3.93 0.17 5 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.10 152.89 22:39: 10.74 -0.896 33.30 35.58 5.0 6.7 -99.0 -3.009 0.105 10.00 3 -99.00
YBH 6.68 140.87 22:40: 21.77 1.982 101.14 101.59 3.9 2.2 -99.0 -0.398 0.189 8.30 1 -99.00
ULM 20.83 236.67 22:43: 18.10 1.062 278.60 282.32 3.8 3.0 -99.0 -0.429 0.208 7.50 1 -99.00
YKA 26.16 185.29 22:44: 12.81 -0.647 334.93 337.18 3.2 3.5 -99.0 -0.824 0.063 8.00 3 -99.00
KURK 92.18 12.87 22:51: 46.49 -1.609 789.64 790.50 3.6 3.5 -99.0 -0.523 0.089 7.00 5 -99.00
8 7564944 23: 0: 48.67 0.07 37.976 -116.613 0.0 1.18 0.87 3 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.49 108.31 23: 1: 15.04 0.024 26.43 28.03 5.1 5.0 -99.0 -2.487 0.085 10.00 4 -99.00
ELK 2.64 -158.57 23: 1: 44.70 0.066 55.94 49.80 3.6 16.2 -99.0 -1.667 0.034 9.00 5 -99.00
PDAR 6.89 231.57 23: 2: 59.35 -0.099 130.76 125.28 3.8 7.5 -99.0 -0.379 0.070 9.00 3 -99.00
9 24060380 23:55: 22.32 1.04 37.442 -117.985 0.0 3.70 0.39 6 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.32 165.62 23:55: 41.27 -0.421 19.48 25.15 4.5 3.2 -99.0 -3.256 0.017 10.00 3 -99.00
ELK 3.94 -146.30 23:56: 24.78 0.270 62.15 62.30 5.5 2.5 -99.0 -1.897 0.024 9.00 3 -99.00
YKA 25.34 185.53 0: 0: 48.78 0.364 326.17 327.80 3.8 5.7 -99.0 -0.101 0.074 8.00 3 -99.00
ILAR 32.57 133.47 0: 1: 52.88 0.314 390.28 392.67 3.0 6.3 -99.0 -0.140 0.199 8.00 2 -99.00
USRK 77.39 50.02 0: 7: 19.01 1.455 715.29 717.36 3.3 2.9 -99.0 0.161 0.213 5.50 2 -99.00
ZALV 87.14 17.72 0: 8: 7.13 -1.967 766.83 768.12 3.3 4.6 -99.0 -0.119 0.135 6.50 5 -99.00
5/1/26
Nevada Test Site seismicity on January 20, 2026 recovered using waveform cross correlation
Following my previous post on the recovery of seismic events at the Nevada Test Site on June 22, 2020 and around, it's to continue to trace the evolution of seismic regime at the NTS. Start with January 20, 2026 and then continue at a daily basis. Figure below shows the locations of 27 master events and the events found ny cross correlation. The corresponding bulletin (XSEL) is given below. (For details please see the previous post)
Figure. Locations of master events (red) and the events found by cross correlation (yellow). The NST center is shown by black circle.
Bulletin.
# MASTER hh:mm:ss ot_stdev Lat Lon Depth Mb mb_stdev ndef NEW ORID SeisReg Ndef(SEL)
1 21946971 1:56: 35.54 0.02 36.949 -114.774 0.0 3.16 0.27 3 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.66 116.83 1:57: 27.29 0.025 51.67 44.12 8.9 596.1 -99.0 -0.226 0.039 10.00 2 -99.00
ELK 3.61 174.40 1:57: 35.36 -0.014 59.74 57.02 9.4 2.9 -99.0 0.157 0.062 9.00 2 -99.00
PDAR 7.18 220.33 1:58: 23.32 -0.011 107.71 109.35 8.4 3.3 -99.0 0.445 0.151 9.00 3 -99.00
2 19344894 2: 7: 26.32 1.64 35.978 -117.387 0.0 3.95 0.57 5 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.10 163.14 2: 8: 11.31 1.971 42.81 35.58 5.5 3.1 -99.0 -3.247 0.029 10.00 2 -99.00
PDAR 8.81 226.64 2: 9: 38.98 -1.904 134.70 131.12 3.8 3.3 -99.0 -1.477 0.072 9.00 2 -99.00
ANMO 9.10 282.50 2: 9: 41.12 1.886 132.78 134.44 3.7 2.2 -99.0 -0.423 0.139 8.50 2 -99.00
ZALV 87.95 17.84 2:20: 18.38 -1.070 773.22 771.07 3.2 3.7 -99.0 -0.093 0.155 6.50 3 -99.00
BVAR 90.66 6.35 2:20: 31.73 -1.079 786.56 784.47 3.2 3.0 -99.0 -0.092 0.139 7.00 2 -99.00
3 21946971 2:28: 5.08 1.12 37.244 -115.056 0.0 2.19 0.77 4 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.66 113.80 2:28: 52.38 0.630 46.63 44.12 5.6 7.6 -99.0 -1.648 0.090 10.00 2 -99.00
ELK 3.61 177.62 2:28: 58.81 -1.665 55.48 57.02 6.9 3.3 -99.0 -1.540 0.053 9.00 3 -99.00
PDAR 7.18 220.33 2:29: 52.69 1.314 106.13 109.35 3.1 2.2 -99.0 -0.309 0.054 9.00 3 -99.00
TXAR 12.50 311.49 2:31: 4.22 -0.308 179.43 181.06 3.8 3.9 -99.0 0.133 0.283 8.50 2 -99.00
4 15999493 8:20: 34.53 0.11 36.175 -116.262 0.0 2.95 0.44 4 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 3.30 143.60 8:21: 18.70 -0.003 44.15 52.36 7.3 97.9 -99.0 -1.562 0.072 10.00 2 -99.00
ELK 4.92 184.90 8:21: 44.90 -0.179 70.66 74.67 9.7 9.5 -99.0 -1.219 0.168 9.00 2 -99.00
PDAR 8.43 216.77 8:22: 39.78 0.125 125.10 125.77 6.4 4.8 -99.0 -0.939 0.097 9.00 3 -99.00
TXAR 12.07 305.55 8:23: 36.63 0.063 182.08 175.75 3.6 9.3 -99.0 -0.359 0.140 8.50 3 -99.00
5 24060380 14:42: 12.79 0.69 37.090 -118.120 0.0 3.27 0.79 5 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.32 173.77 14:42: 37.84 -0.552 25.67 25.15 5.5 3.1 -99.0 -3.356 0.095 10.00 4 -99.00
ELK 3.94 -147.56 14:43: 20.68 0.810 67.05 62.30 3.3 2.5 -99.0 -2.160 0.017 9.00 3 -99.00
YBH 5.99 136.76 14:43: 40.62 0.732 86.97 89.01 3.6 3.3 -99.0 -0.102 0.497 8.30 1 -99.00
YKA 25.34 185.53 14:47: 41.22 -0.937 329.45 327.80 3.7 4.4 -99.0 -0.298 0.110 8.00 3 -99.00
USRK 77.39 50.02 14:54: 8.99 -0.152 716.29 717.36 3.2 3.0 -99.0 0.139 0.274 5.50 2 -99.00
6 24060380 18:50: 11.13 1.02 37.507 -117.570 0.0 3.76 0.74 6 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.32 147.68 18:50: 30.25 -1.508 20.78 25.15 8.9 34.6 -99.0 -2.546 0.156 10.00 3 -99.00
ELK 3.94 -150.07 18:51: 11.61 1.219 59.09 62.30 4.5 3.1 -99.0 -1.487 0.098 9.00 1 -99.00
YBH 5.99 136.76 18:51: 38.97 1.345 86.27 89.01 3.3 5.1 -99.0 -0.000 0.391 8.30 1 -99.00
ANMO 9.28 287.52 18:52: 29.07 -0.322 138.26 137.52 3.3 3.6 -99.0 0.679 0.484 8.50 1 -99.00
TXAR 14.04 307.79 18:53: 34.98 -0.015 203.79 202.18 3.5 3.4 -99.0 0.034 0.090 8.50 4 -99.00
ULM 20.27 238.38 18:54: 45.85 -0.792 275.49 277.57 3.2 4.1 -99.0 0.019 0.313 7.50 2 -99.00
7 14628102 19:23: 13.12 0.07 36.476 -115.335 0.0 -1.39 0.50 3 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.49 128.75 19:24: 3.55 0.074 50.46 41.67 6.6 16.2 -99.0 -1.947 0.064 10.00 2 -99.00
ELK 4.04 188.61 19:24: 18.38 0.018 65.35 62.30 5.6 3.2 -99.0 -1.475 0.046 9.00 2 -99.00
PDAR 7.80 221.58 19:25: 8.15 -0.091 115.22 116.42 3.1 4.4 -99.0 -0.737 0.057 9.00 2 -99.00
8 24060380 19:24: 30.41 1.15 37.200 -117.598 0.0 3.72 0.53 5 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 1.32 155.38 19:24: 57.60 1.329 25.73 25.15 8.0 8.0 -99.0 -2.930 0.133 10.00 2 -99.00
ELK 3.94 -151.90 19:25: 32.87 -0.550 62.97 62.30 4.4 3.0 -99.0 -1.977 0.060 9.00 2 -99.00
YBH 5.99 136.76 19:25: 57.75 -1.870 89.28 89.01 3.3 3.9 -99.0 0.013 0.359 8.30 1 -99.00
ANMO 9.28 287.52 19:26: 48.34 0.174 137.70 137.52 3.3 2.8 -99.0 0.111 0.207 8.50 3 -99.00
PETK 58.33 69.01 19:34: 28.78 1.009 597.36 597.25 3.6 3.1 -99.0 0.230 0.183 7.00 2 -99.00
9 10374180 23:53: 1.92 0.01 37.654 -114.509 0.0 2.03 0.69 3 NEW 0 3
sta delta azim hh:mm:ss res,s travel time master TT SNRcc SNR SNRIDC dRM CC sta_weight filter tREBres
NVAR 2.60 103.38 23:53: 51.68 0.013 49.65 42.61 4.9 5.7 -99.0 -2.024 0.081 10.00 2 -99.00
ELK 3.04 169.40 23:53: 52.18 0.006 50.20 48.86 4.0 2.1 -99.0 -1.451 0.019 9.00 2 -99.00
PDAR 6.62 221.99 23:54: 38.98 -0.020 97.08 100.59 3.4 3.1 -99.0 -0.353 0.070 9.00 4 -99.00
Seismic noise suppression: array stations, waveform cross-correlation, and noise stochastization
Full paper available on arXiv.org
Abstarct
Seismic noise with an amplitude higher than that of the sought signal is a challenge for detection. Several techniques have been developed to suppress the ambient noise and to reduce the detection threshold in order to find signals with the lowest possible amplitudes produced by events with the magnitudes significant for scientific research and technical applications. Seismic arrays were introduced in the late 1950s as a method for improving underground test monitoring, potentially reducing detection thresholds by fivefold or more by exploiting destructive interference effects of a quasi-random noise. The beamforming method is the backbone of data processing at the International Data Centre (IDC) with more than 30 array stations of the International Monitoring System (IMS) installed around the globe. The matched filter method allows for the suppression of noise incoherent to the sought signal. It employs waveform cross-correlation (WCC) with templates based on actual and simulated seismic signals to improve the signal-to-noise ratio estimates for similar signals. The performance of this method is significantly enhanced when it is applied to a seismic array. A novel technique combined with WCC, is the noise stochastization or the addition of scaled random noise to the actual data before calculating the cross-correlation coefficient. The stochastic component can easily be generated by a computer program. Alternatively, a regular signal propagating at an angle of around 90° to the plane of the sought signal can play a role of stochastic component at array stations. We demonstrate the separate and joint effects of these noise reduction techniques on the WCC performance, when applied to filtered data from selected IMS arrays and various waveform templates of historical events available at the IDC.
Key words: waveform cross
correlation, seismic array, noise stochastization, filtering, International
Monitoring System, International Data Centre
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