Nuclear explosion locations at the Balapan, Kazakhstan, nuclear test site: the effects of high-precision arrival times and three-dimensional structure

Thurber, C. H.; Trabant, Chad; Haslinger, Florian; Hartog, J. Renate

doi:10.1016/s0031-9201(00)00215-6

Cited by 29 publications

(20 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this report we showed two examples of aftershocks buried in the coda of mainshocks that can be detected and weren't listed in the ABCE. Waveform cross correlation can also be used in discrimination when a signal correlates with a known explosion in the case of mining activity (Israelsson 1990;Harris 1991;Riviere-Barbier & Grant 1993) and nuclear explosions (Shearer & Astiz 1997;Thurber et al 2001;Fisk 2002;). This issue of screening out earthquakes is very useful for large aftershock sequences such as those of the recent May 12, 2008, earthquake in China.…”

Section: Discussionmentioning

confidence: 99%

Improving Magnitude Detection Thresholds Using Multi-Station Multi-Event, and Multi-Phase Methods

Schaff¹,

Waldhauser²

2008

View full text Add to dashboard Cite

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. (31-07-2008) REPORT DATE SPONSOR/MONITOR'S ACRONYM(S)AFRL/RVBYE SPONSOR/MONITOR'S REPORT NUMBER(S) AFRL-RV-HA-TR-2008-1121 DISTRIBUTION / AVAILABILITY STATEMENTApproved for Public Release; Distribution Unlimited. SUPPLEMENTARY NOTES ABSTRACTWe report on the results of both a semi-empirical analysis and a case study in Xiuyan, China, that demonstrated that a correlation detector can lower magnitude detection thresholds by over one full unit for similar events as compared to a standard STA/LTA detector. 90 out of 90 events (100%) were detected by cross correlation for the case study whereas a procedure like the pIDC employs detected only 11%. We found that less than perfect matches still provided useful detections due to location, focal mechanism, and magnitude differences. Events with magnitude differences as large as 2.3 and 3.3 were shown to produce detection spikes on the correlation traces. Further work applied the correlation techniques on a larger scale to 5,000 events at Parkfield, California, and 19,000 events in and near China. We are attempting to see how broadly applicable correlation methods can be applied to different tectonic settings and for what percentage of the seismicity. 111 million correlations were performed on Lg-waves for the events in China at 363 stations. Final results indicate two thirds of the 19,000 events can be detected by cross correlation using this relatively sparse regional network. The full magnitude unit reduction in detection threshold is confirmed on a large scale in China and Parkfield.

show abstract

Section: Discussionmentioning

confidence: 99%

Improving Magnitude Detection Thresholds Using Multi-Station Multi-Event, and Multi-Phase Methods

Schaff¹,

Waldhauser²

2008

View full text Add to dashboard Cite

show abstract

“…Precise ''ground truth'' origin times and depths of burial are available for 10 UNE between 1985 and 1989 [Adushkin et al, 1997]. For all UNE, teleseismically determined origin times are available from multiple sources, such as the International Seismological Centre (ISC) and Thurber et al [2001].…”

Section: Data and Local Geologymentioning

confidence: 99%

Phase composition of regional seismic waves from underground nuclear explosions

Hong

Xie

2005

J. Geophys. Res.

View full text Add to dashboard Cite

1] The mechanism of regional shear wave excitation by underground nuclear explosions (UNE), a long-standing issue in nuclear seismology, is investigated by studying the phase composition of regional waves from clustered UNE. Regional seismic waves from 67 UNE at the Balapan test site of Kazakhstan, recorded at station Borovoye, are analyzed with a source array technique under the reciprocity theorem. This analysis allows one to obtain the phase velocity composition of the plane waves leaving the source region. Source locations and the original times are obtained from geodetic measurements, a scaling law between event magnitude and depth, and a calibrated Pn travel time curve. Between frequencies of 0.5 and 3.0 Hz the Pn slowness power spectra are concentrated at a phase velocity (v h ) of 8.0 km/s. The expected Sn window contains two dominant phases: a scattered P wave with a v h of around 7.1 km/s and a mantle shear wave with a v h of 4.8 km/s. The Lg waves are coherent between 0.5 and 2.0 Hz, with a dominant v h of 4.2 km/s, which is typical in SmS-type waves. The Rg wave at frequencies between 0.5 and 0.8 Hz is dominantly composed of a coherent fundamental mode Rayleigh wave with a v h of 3.0 km/s. At higher frequencies (>0.8 Hz) this coherent Rayleigh wave is not observed in the Rg window because of attenuation during wave propagation. The slower v h of Rg and faster v h of Lg, at which the strong coherent peaks in slowness power spectra are observed, suggest that the dominant components of these two waves are different and they are originated differently in the source region. The proposed Rg-to-S scattering does not appear to be a dominant mechanism for Lg excitation in the Balapan test site. It is also found that the strength of shear waves contained in the expected Sn window varies with local geology much more than the strength of Lg does. Since the Sn is enriched in high-frequency (>1 Hz) content as compared to the Lg, this observation suggests that the local geology influences shear wave excitation at high frequencies more than at lower frequencies.Citation: Hong, T.-K., and J. Xie (2005), Phase composition of regional seismic waves from underground nuclear explosions,

show abstract

“…Geller & Mueller (1980) recognised a set of events which resulted in almost identical waveforms when filtered in a sufficiently low frequency band, concluding that the source locations of the events could not be separated by more than a quarter of the dominant wavelength. Waveform correlation has been used to measure very small differential travel-times from event pairs recorded at a network of stations to provide highly improved relative location estimates of nuclear explosions (Shearer & Astiz 1997;Thurber et al 2001;Phillips et al 2001;Waldhauser et al 2004) and earthquakes (e.g., Poupinet et al 1984;Shearer 1997;Astiz & Shearer 2001;Shearer et al 2003;Du et al 2004). The double difference (DD) techniques (e.g.…”

Section: Introductionmentioning

confidence: 99%

The detection of low magnitude seismic events using array-based waveform correlation

Gibbons¹,

Ringdal²

2017

Preprint

114

153

View full text Add to dashboard Cite

SUMMARYIt has long been accepted that occurrences of a known signal are most effectively detected by cross-correlating the incoming data stream with a waveform template. Such matched signal detectors have received very little attention in the field of detection seismology because there are relatively few instances in which the form of an anticipated seismic signal is known a priori. Repeating events in highly confined geographical regions have been observed to produce very similar waveforms and good signals from events at a given site can be exploited to detect subsequent co-located events at lower magnitudes than would be possible using traditional power detectors. Even greater improvement in signal detectability can be achieved using seismic arrays; running correlation coefficients from single sensors can be stacked over an array or network to result in a network correlation coefficient displaying a significant array gain. If two events are co-located, the time separating the corresponding patterns in the wavetrain as indicated by the cross-correlation function is identical for all seismic stations and this property means that the correlation coefficient traces are coherent even when the waveforms are not. We illustrate the power of array-based waveform correlation using the 16 August 1997 Kara Sea event. The weak event which occurred four hours after the main event was barely detected using an STA/LTA detector on the SPITS array but is readily detected by signal matching on a single channel. The main event was also recorded by the far more distant NORSAR array but no conventional detection can be made for the second event. A clear detection is however made when the correlation coefficient traces are beamformed over all sensors of the array. We estimate the reduction in detection threshold of a test signal on a regional seismic array using waveform correlation by scaling down a master signal and immersing it into seismic noise. We show that, for this case, waveform correlation using a single channel detects signals of approximately 0.7 orders of magnitude lower than is possible using an STA/LTA detector on the array beam. Waveform matching on the full array provides an additional improvement of approximately 0.4 magnitude units. We describe a case study in which small seismic events at the Barentsburg coal mine on Spitsbergen were detected using the signals from a major rockburst as master waveforms. Many spurious triggers occurred in this study whereby short sections of signal exhibited coincidental similarity with unrelated incoming wavefronts. We demonstrate how such false alarms can almost always be identified and screened out automatically by performing frequency-wavenumber analysis upon the set of individual correlation coefficient traces.

show abstract

Nuclear explosion locations at the Balapan, Kazakhstan, nuclear test site: the effects of high-precision arrival times and three-dimensional structure

Cited by 29 publications

References 16 publications

Improving Magnitude Detection Thresholds Using Multi-Station Multi-Event, and Multi-Phase Methods

Improving Magnitude Detection Thresholds Using Multi-Station Multi-Event, and Multi-Phase Methods

Phase composition of regional seismic waves from underground nuclear explosions

The detection of low magnitude seismic events using array-based waveform correlation

Contact Info

Product

Resources

About