Source parameters of some presumed Semipalatinsk underground nuclear explosions

1973 ◽  
Vol 102 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Ota Kulh�nek
Keyword(s):  
Source Parameters ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions

Prediction of peak ground motion from earthquakes

1974 ◽  
Vol 64 (5) ◽  
pp. 1563-1574 ◽  
Author(s):  
D. L. Orphal ◽  
J. A. Lahoud
Keyword(s):  
Peak Velocity ◽  
Source Parameters ◽  
Focal Distance ◽  
Maximum Acceleration ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Peak Ground Motion ◽  
San Fernando ◽  
Peak Horizontal Acceleration ◽  
Using Data

Abstract A statistical analysis shows that the peak horizontal accelerations recorded from the San Fernando earthquake of February 1971 attenuate with focal distance as R−1.39. This attenuation rate is nearly identical to that reported for peak accelerations from underground nuclear explosions. Assuming that the derived attenuation is independent of source parameters and using data from a number of other California earthquakes, the scaling of peak horizontal acceleration with magnitude was determined statistically. Assuming that the attenuation of peak velocity and displacement with distance is identical for earthquakes and underground nuclear explosions, the scaling of earthquake peak velocity and displacement with magnitude was also determined. The equations resulting from these analyses are: a = 6.6 × 10−2 100.40MR−1.39, v = 7.26 × 10−1 100.52M R−1.34 and d = 4.71 × 10−2 100.57MR−1.18, where a, v, and d are maximum acceleration (g), velocity (in centimeters per second) and displacement (in centimeters), respectively, M is the local magnitude, and R is the focal distance (in kilometers). In this analysis, no attempt was made to account for effects of recording site geology.

scholarly journals Discriminating underground nuclear explosions leading to late-time radionuclide gas seeps

2020 ◽  
Author(s):  
Dylan Robert Harp ◽  
Suzanne Michelle Bourret ◽  
Philip H. Stauffer ◽  
Ed Michael Kwicklis
Keyword(s):  
Late Time ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Gas Seeps

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.

Could the Beirut Explosion perturb the Ionosphere? Pre-results Using TEC-GNSS observations.

2021 ◽  
Author(s):  
Mohamed Freeshah ◽  
Xiaohong Zhang ◽  
Erman Şentürk ◽  
Xiaodong Ren ◽  
Muhammad Arqim Adil ◽  
...  
Keyword(s):  
Ammonium Nitrate ◽  
Space Weather ◽  
Global Navigation Satellite Systems ◽  
Electron Content ◽  
Free Electrons ◽  
Total Electron ◽  
Satellite Systems ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Global Navigation Satellite

<p>Natural hazards such as shallow earthquakes and volcanic explosions are known to generate acoustic and gravity waves at infrasonic velocity to propagate in the atmosphere layers. These waves could induce the layers of the ionosphere by change the electron density based on the neutral particles and free electrons coupling. Recently, some studies have dealt with some manmade hazards such as buried explosions and underground nuclear explosions which could cause a trigger to the ionosphere. The Global Navigation Satellite Systems (GNSS) provide a good way to measure ionospheric total electron content (TEC) through the line of sight (LOS) from satellite to receiver. The carrier-to-code leveling (CCL) technique is carried out for each continuous arc where CCL eliminates potential ambiguity influence and it degrades the pseudo-range noise. Meanwhile, the CCL retains high precision in the carrier-phase. In this study, we focus on the Beirut Explosion on August 4, 2020, to check slant TEC (STEC) variations that may be associated with the blast of Beirut Port. The TECs were analyzed through the Morlet wavelet to check the possible ionospheric response to the blast. An acoustic‐gravity wave could be generated by the event which could disturb the ionosphere through coupling between solid earth-atmosphere-ionosphere during the explosion. To verify TEC disturbances are not associated with space weather, disturbance storm-time (Dst), and Kp indices were investigated before, during, and after the explosion. The steady-state of space weather before and during the event indicated that the observed variations of TEC sequences were caused by the ammonium nitrate explosion. There was a large initial explosion, followed by a series of smaller blasts, about ~30 seconds, a colossal explosion has happened, a supersonic blast wave radiating through Beirut City. As a result of the chemistry behind ammonium nitrate’s explosive, a mushroom cloud was sent into the air. We suggest that these different explosions in strength and time could be the reason for different time arrival of the detected ionospheric disturbances over GNSS ground-based stations.</p>

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.

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