Nuclear Testing Geology Mitigation Safety

US Geological Survey Report

UNCLASSIFIED REPORT NO. 01-28

Engineering and Geological Constraints on the Feasibility of Underground Nuclear Testing in Large Cavities with Explosion Decoupling (Mitigation).

Dr. William Leith
US Geological Survey
Reston, Virginia 20192

U.S. Department of the Interior

Geological Assessment

Until very recently, this report could be downloaded from the USGS Publications site at:

http://geology.er.usgs.gov/eespteam/pdf/USGSOFR0128.pdf

This report is no longer available, even in USGS databases (http://search.usgs.gov/).

A backup copy is available here: http://membres.lycos.fr/atar/Archives/Report01_28.pdf

We owe this providential backup to the foresight of Christophe Giudicci, who discovered its existence. It is a key document in the "clandestine nuclear testing" dossier. This dossier was submitted to the judge during the 2003 Appeal trial in which I was opposed to Antoine Giudicelli, resulting in my conviction for defamation. I extensively commented on it during the hearing when the judge requested "to get to the heart of the matter." It was not mentioned in the judgment. See also the comments on the judgment.

Here is a brief overview of the report's content.

Preliminary Work

For the preceding 40 years, the US Geological Survey's geological monitoring office maintained its efforts to monitor nuclear tests worldwide and ensure compliance with relevant treaties.

• Nuclear explosion detection systems – Surface and environmental effects, primarily related to foreign tests. Location of test sites.
• Assessments of so-called "nuclear tests conducted for peaceful purposes."
• Comparative studies of seismic effects from nuclear explosions versus those caused by natural seismicity and mining-related explosions.
• Participation in the development of nuclear test ban treaties.
• Establishment of seismic databases to facilitate nuclear explosion detection – Discrimination between nuclear explosions and earthquake signals.
• Studies on wave attenuation through the Earth's crust.
• Study of the natural attenuation capacity of porous soils at various depths (Matzko, 1995).
• Natural cavities suitable for decoupling devices, focusing on salt domes, salt layers, or areas conducive to the development of large underground caverns.

A Decoupling Scenario

One of the main challenges in nuclear non-proliferation treaties (Comprehensive Nuclear-Test-Ban Treaty or CTBT) is assessing whether countries could conduct tests covertly—i.e., undetected by standard monitoring systems. Among the various possible scenarios are:

• Detonating a nuclear charge in space
• During an earthquake
• In a medium offering natural attenuation
• In a remote marine environment
• In the Earth's atmosphere under heavy cloud cover
• By avoiding detection through detonation in sufficiently large cavities at adequate depths.

All these methods have been the subject of extensive study, and numerous articles have been published on the topic (Herbst and Werth, 1980; Glenn and Goldstein, 1994; Sykes, 1995; Linger et al., 1995).

Since Albert Latter first proposed the idea of detonating a charge in a cavity in 1959 (Latter et al., 1961), considerable work has been done to theoretically model this phenomenon. The USA and USSR conducted tests under decoupling conditions, as reported in Springer et al., 1968; Murphy & al., 1995; Reinke, 1995.

In 1988, it was concluded that monitoring could detect explosions exceeding 10 kilotons, and with such yields, there were no methods capable of eliminating the seismic signal.

For yields below one to two kilotons, it was concluded that tests could be conducted in violation of treaties in media such as granite, alluvium, or salt deposits, and that no reliable detection methods currently exist with existing technology.

Between these two ranges (charges above 10 kilotons or below 1 kiloton), there is a range where, if decoupling techniques are employed, detection remains problematic.

The purpose of this paper is to review decoupling techniques involving detonation within cavities (Sykes, 2000). This review focuses on air-filled cavities. However, other attenuation methods have also been considered. Attention has been given to porous, cellular materials capable of collapsing during explosion, thereby absorbing energy. The feasibility of underground nuclear tests in cellular rocks with porosity ranging from 5% to 20% has been demonstrated. There are regions, such as the Kalahari, where porosity can exceed 20%.

Here are the criteria that would allow for the execution of stealthy nuclear explosions:

• The seismic signal must remain below the detection threshold of monitoring instruments.
• The test depth must be sufficient to ensure confinement of radioactive products after the explosion, so that radioactive detection systems cannot identify the event, distinguishing it from natural signals.
• The test site must be designed to evade satellite surveillance.

Attenuation in Ellipsoidal Cavities

Americans and Soviets conducted numerous tests using high-power chemical explosives in cavities with elongation ratios up to 4:1. In the Soviet Union, these tests were carried out in Kyrgyzstan in 1960. Similar tests were conducted in Magdalena, New Mexico, in 1994. These tests were performed to verify the accuracy of predictive models.

Attenuation Factor in Salt and Granite

According to a 1988 report by the OTA, spherical cavity diameters of 25 meters in salt and 20 meters in granite could provide sufficient attenuation for a one-kiloton charge, with the charges detonated at depths of 825 meters. Sykes (1995) estimates that these assessments should be revised upward, but the adjustments remain minor, and these values can be considered significant.

Environmental Conditions for Underground Cavity Development

The decoupling technique...