Study of low-magnitude seismic events near the Novaya Zemlya nuclear test site

1997 ◽  
Vol 87 (6) ◽  
pp. 1563-1575
Author(s):  
Frode Ringdal
Keyword(s):  
Monitoring Network ◽  
Test Site ◽  
Nuclear Test ◽  
P Wave ◽  
Scaling Effects ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Novaya Zemlya ◽  
Source Scaling ◽  
Low Magnitude

Abstract A study of available seismic data shows that all but one of the 42 known underground nuclear explosions at Novaya Zemlya have been detected and located by stations in the global seismic network. During the past 30 years, only one seismic event in this area has been unambiguously classified as an earthquake (1 August 1986, mb = 4.3). Several other small events, most of which are thought to be either chemical explosions or aftereffects of nuclear explosions, have also been detected. Since 1990, a network of sensitive regional arrays has been installed in northern Europe in preparation for the global seismic monitoring network under a comprehensive nuclear test ban treaty (CTBT). This regional network has provided a detection capability for Novaya Zemlya that is shown to be close to mb = 2.5. Three low-magnitude events have been detected and located during this period, as discussed in this article: 31 December 1992 (mb = 2.7), 13 June 1995 (mb = 3.5), and 13 January 1996 (mb = 2.4). To classify the source types of these events has proved very difficult. Thus, even for the mb = 3.5 event in 1995, we have been unable to provide a confident classification of the source as either an earthquake or explosion using the available discriminants. A study of mb magnitude in different frequency bands shows, as expected, that the calculation of mb at regional distances needs to take into account source-scaling effects at high frequencies. Thus, when comparing a 4 to 8 or 8 to 16 Hz filter band to a “teleseismic” 2 to 4 Hz band, the smaller events have, relatively speaking, significantly more high-frequency energy (up to 0.5 mb units) than the larger events. This suggests that a P-wave spectral magnitude scale might be appropriate. The problem of accurately locating small events using a sparse array network is addressed using the 13 January 1996 event, which was detected by only two arrays, as an illustrative example. Our analysis demonstrates the importance of using accurately calibrated regional travel-time curves and, at the same time, illustrates how array processing can be used to identify an interfering phase from a local disturbance, thereby avoiding location errors due to erroneous phase readings.

Seismic magnitudes of underground nuclear explosions

1973 ◽  
Vol 63 (1) ◽  
pp. 105-131 ◽  
Author(s):  
P. W. Basham ◽  
R. B. Horner
Keyword(s):  
Computational Procedure ◽  
Test Site ◽  
P Wave ◽  
Nevada Test Site ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Novaya Zemlya ◽  
Yield Information ◽  
Short Period ◽  
Propagation Effects

abstract Using an Ms computational procedure that minimizes path-propagation effects, and with Ms values found to be empirically independent of test site and detonation medium among consolidated rock explosions, available yield information is employed to illustrate that the seismic scaling of explosions in realistic detonation environments produces teleseismic Rayleigh-wave displacements proportional to the 1.2-power of yield over the range from low yields to greater than three megatons. Ms values independent of network, path, and site can be employed to estimate unknown yields at uncalibrated test sites to within average errors judged to be about 20 per cent. P-wave magnitudes, in the form of a calibrated teleseismic measure of short-period P-wave displacements, show a theoretically supported dependence of displacement on the 1.1-power of yield over the range from 6 kt to 1 mt. Studied explosions separate into two categories: the Nevada Test Site granite explosions, LONG SHOT, the Sahara February 1965 explosion and (by empirical inference) Novaya Zemlya and Eastern Kazakh explosions exhibit P-wave displacements about a factor of 3 greater than explosions of the same yield in tuff, rhyolite, and shale. P-wave magnitudes of explosions are subject to such a diversity of source, propagation, and measurement phenomena that any estimation of unknown yields without a closely controlled site and network calibration can be subject to large errors.

Lg magnitudes and yield estimates for underground Novaya Zemlya nuclear explosions

1988 ◽  
Vol 78 (2) ◽  
pp. 873-884
Author(s):  
Otto W. Nuttli
Keyword(s):  
Large Range ◽  
Test Site ◽  
Nevada Test Site ◽  
P Values ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Novaya Zemlya ◽  
Short Period ◽  
Lg Wave ◽  
Range Of Values

Abstract Lg-wave amplitudes of 30 Novaya Zemlya underground nuclear explosions, as recorded by short-period seismographs in Denmark, Finland, Germany, Norway, Spitsbergen, and Sweden, are used to determine mb(Lg) values. Assuming that the mb(Lg) versus explosion yield relation derived from Nevada Test Site data applies to all continental areas, the yields of the explosions are estimated. They cover a large range of values, from 2.5 to 4900 kt. The largest explosion since April 1976 had an estimated yield of 145 kt. The mb(Lg) values, when subtracted from the mb(P) values, can be used to estimate the mb(P) bias between two test sites. In this way, the mb(P) bias between Novaya Zemlya and the Nevada Test Site is estimated to be 0.20 magnitude units.

Effects of Secondary Sources of Underground Nuclear Explosions on the mb : Ms Criterion and Implications for Discrimination of the DPRK’s Nuclear Tests

2020 ◽  
Author(s):  
Henglei Xu ◽  
Sidao Ni ◽  
Ping Jin ◽  
Shiban Ding ◽  
Hongchun Wang
Keyword(s):  
Body Wave ◽  
Test Site ◽  
Nuclear Test ◽  
Source Spectrum ◽  
Secondary Source ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Secondary Sources ◽  
Nuclear Tests ◽  
Recognition Criterion

ABSTRACT The mb :  Ms (mb vs. Ms) relationship is an important criterion for screening explosions from earthquakes and has been widely adopted in seismological monitoring by the Comprehensive Nuclear-Test-Ban Treaty Organization. In general, the earthquakes have larger Ms than the underground explosions with equivalent mb. However, it has been reported that this recognition criterion failed to identify some explosions at the North Korea nuclear test site. In this study, we investigate the potential effects of secondary source components, including the compensated linear vector dipole (CLVD) and double-couple (DC) sources, on mb and Ms magnitude measurements and the physical mechanism of the mb :  Ms recognition criterion by calculating synthetic seismograms. The results show an apparent critical body-wave magnitude of 5 when using the mb :  Ms method to discriminate North Korean underground nuclear explosions. The Ms measurements decrease as the CLVD components increase, whereas the effects from the DC source can be neglected. Small events, such as the first five North Korean nuclear tests, generate weak CLVD components, leading to the failure of mb :  Ms-based discrimination, whereas the last event, with a larger magnitude, caused extensive damage and hence can be successfully discriminated. In addition, the large difference between the source spectrum of explosions and those of earthquakes might be another important factor in the successful mb :  Ms-based discrimination of the sixth North Korean nuclear test.

Amplitude-yield scaling for underground nuclear explosions

1973 ◽  
Vol 63 (2) ◽  
pp. 477-500 ◽  
Author(s):  
D. L. Springer ◽  
W. J. Hannon
Keyword(s):  
Rayleigh Wave ◽  
Statistical Tests ◽  
Test Site ◽  
Mean Value ◽  
P Wave ◽  
Source Population ◽  
Yield Data ◽  
P Waves ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions

abstract About 60 sets of seismic amplitude-yield data were examined using standard regression techniques to determine slopes of amplitude-yield scaling relations for explosions in water-saturated tuffs and rhyolites. Both P-wave amplitudes and Rayleigh-wave amplitudes were studied at selected stations located at regional and teleseismic distances. The source population included only those underground nuclear explosions fired near or below the level of the static water table at Pahute Mesa, Nevada Test Site, and covered about three orders of magnitude in yield. Statistical tests applied to the slope parameter (b) indicate that the slopes at regional and teleseismic distances are different. An estimated mean value of b for P-wave amplitude/period (A/T) was slightly greater than 0.6 for regional distances but was almost 1.0 for teleseismic distances. The estimated mean value of b for Rayleigh-wave A/T data was about 1.1. At a given distance the slopes seem to be independent of the yield range considered for both P-waves and Rayleigh-waves.

The stability of rms Lg measurements and their potential for accurate estimation of the yields of Soviet underground nuclear explosions

1990 ◽  
Vol 80 (6B) ◽  
pp. 2106-2126
Author(s):  
Roger A. Hansen ◽  
Frode Ringdal ◽  
Paul G. Richards
Keyword(s):  
Soviet Union ◽  
Signal To Noise Ratio ◽  
Test Site ◽  
P Wave ◽  
Accurate Estimation ◽  
Seismic Stations ◽  
Array Data ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Single Station

Abstract Data on underground nuclear explosions have recently become available from modern digital seismic stations installed within the Soviet Union and China. Observations of root mean square (rms) Lg-wave signals for Soviet underground nuclear explosions at the Shagan River Test Site in East Kazakhstan show that the relative amplitudes of the rms signals at stations in Norway, the USSR, and China are very similar for different explosions, the standard deviation of the differences being only about 0.03 in logarithmic units (i.e., magnitude units). This is consistent with earlier observations comparing NORSAR and Graefenberg array data, and the observed scatter is significantly lower than has been reported for Lg data from Nevada Test Site explosions. In view of the excellent correspondence found by Nuttli (1986) and Patton (1988) for Lg versus yield at Nevada, this indicates that rms Lg has a potential for yield estimation with very high accuracy at Shagan River. Our study has shown that: (a) selected stations in the USSR and China, situated at regional distances, provide a much improved signal-to-noise ratio of the Lg phase for events at Shagan River, as compared to NORSAR array data; (b) the scaling of rms Lg amplitudes between different-sized events recorded at the same single station site appears to be consistent with that of NORSAR, indicating a remarkable degree of precision in single station measurements of Lg signal; (c) rms Lg amplitude measurements for the best of these stations may be made at 1.5 to 2.0 magnitude units lower than at NORSAR or Graefenberg, allowing a much lower threshold for Lg-based yield determination; and (d) the P-wave detection capabilities of these single stations do not match those of the NORESS and ARCESS arrays; thus, teleseismic signals continue to be important for detection of small nuclear explosions. Our conclusion is that Lg signals appear to provide an excellent basis for supplying estimates of the yields of nuclear explosions even down to below 1 kt when such signals are recorded at high-quality, digital in-country seismic stations, and when calibrated by access to independent (nonseismic) yield information for a few nuclear explosions at the test sites of interest. In the context of monitoring a low-yield threshold test ban treaty, it will, in addition, be important to take into consideration various environmental conditions in the testing area, such as the possible presence of cavities, and to devise appropriate procedures for on-site observations in this regard.

Evidence of tectonic release from underground nuclear explosions in long-period P waves

1983 ◽  
Vol 73 (2) ◽  
pp. 593-613
Author(s):  
Terry C. Wallace ◽  
Donald V. Helmberger ◽  
Gladys R. Engen
Keyword(s):  
Upper Mantle ◽  
High Stress ◽  
Test Site ◽  
Strike Slip ◽  
Body Waves ◽  
Release Time ◽  
P Waves ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Long Period

abstract In this paper, we study the long-period body waves at regional and upper mantle distances from large underground nuclear explosions at Pahute Mesa, Nevada Test Site. A comparison of the seismic records from neighboring explosions shows that the more recent events have much simpler waveforms than those of the earlier events. In fact, many of the early events produced waveforms which are very similar to those produced by shallow, moderate-size, strike-slip earthquakes; the phase sP is particularly obvious. The waveforms of these explosions can be modeled by assuming that the explosion is accompanied by tectonic release represented by a double couple. A clear example of this phenomenon is provided by a comparison of GREELEY (1966) and KASSERI (1975). These events are of similar yields and were detonated within 2 km of each other. The GREELEY records can be matched by simply adding synthetic waveforms appropriate for a shallow strike-slip earthquake to the KASSERI observations. The tectonic release for GREELEY has a moment of 5 ՠ1024 dyne-cm and is striking approximately 340°. The identification of the sP phase at upper mantle distances indicates that the source depth is 4 km or less. The tectonic release time function has a short duration (less than 1 sec). A comparison of these results with well-studied strike-slip earthquakes on the west coast and eastern Nevada indicate that, if tectonic release is triggered fault motion, then the tectonic release is relatively high stress drop, on the order of several hundred bars. It is possible to reduce these stress drops by a factor of 2 if the tectonic release is a driven fault; i.e., rupturing with the P velocity. The region in which the stress is released for a megaton event has a radius of about 4 km. Pahute Mesa events which are detonated within this radius of a previous explosion have a substantially reduced tectonic release.

scholarly journals Features of creating multi-time thematic animations of the Arctic environment pollution on the example of Novaya Zemlya

2019 ◽  
Vol 1 ◽  
pp. 1-1
Author(s):  
Andrey Medvedev ◽  
Natalia Alekseenko ◽  
Maria Arsentyeva
Keyword(s):  
Time Scales ◽  
Radioactive Contamination ◽  
Arctic Region ◽  
Test Site ◽  
Nuclear Test ◽  
The Arctic ◽  
Novaya Zemlya Archipelago ◽  
Novaya Zemlya ◽  
The Creation ◽  
The Arctic Region

<p><strong>Abstract.</strong> The Arctic region is currently at the next stage of increased interest not only from the Arctic States, but also from the entire world community. The main pollutants in the region are oil and gas products, heavy metals, chemical and radioactive contamination. The Arctic region of the Russian Federation has experienced a strong anthropogenic impact of radionuclides due to the use of nuclear energy. The main source of pollution is nuclear testing. About 132 tests were conducted on Novaya Zemlya, including 87 atmospheric, 3 underwater and 42 underground tests. Another source of radioactive contamination is the operation of the naval and civil nuclear fleet, as well as nuclear power plants (on the Kola Peninsula and in Bilibino). Until 1963, most of the tests were carried out in the atmosphere and under water, but after the signing of the Moscow Treaty on August 5, 1963, which prohibits the testing of nuclear weapons in three environments (under water, in the atmosphere and outer space), all tests were carried out underground, in tunnels and wells.</p><p>The object of research and mapping is the territory of the Novaya Zemlya archipelago and the nuclear test site located on it. On the territory of the nuclear test site constantly there was an assessment of the radioecological situation. The scientific community is interested in the processes taking place on the New Earth. The territory of the archipelago is constantly involved in various Arctic programs aimed at monitoring the level of environmental pollution and reducing the number of sources of pollution.</p><p>The aim of this work is to create multi-time animations of nuclear tests and the results of radionuclide pollution. These animated cartographic images differ not only in their time scales, but also a large set of qualitative and quantitative characteristics that characterize the results of anthropogenic influence.</p><p>As sources for creation of cartographic animations were: field data, remote sensing data (RS), Open sources, marine navigation maps, DEM’s (AsterDem, ArcticDem, GEBCO), meteorological data, thematic maps (including atlases), topographic maps, literary sources. The main part of the information about Novaya Zemlya archipelago was taken from the works of the Arctic marine complex expedition, which are devoted to the nature, history, archeology and culture of the archipelago. To obtain complete information about the explosions and their energy release ranges, additional open sources were used, from which it is possible to learn about the type of explosion, its power and location (geographical coordinates).</p><p>Dynamic geo-imagery was developed and established by the following method: study of object mapping and the collection of primary spatial data – creation script dynamic geo-imagery – the creation of a geodatabase of research – the creation of the thematic maps and layout of geo-imagery in the graphic editor – create animations with different time scales.</p><p>During the creation of cartographic animations based on the collected data, a multi-time multi-scale cartographic animation was developed, which allowed using the original graphical solution to visualize three interconnected time scales, which allowed to visualize the processes of infiltration and propagation of radioactive inert gases.</p>

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