Primer on Use of Multi-Spectral and Infra Red Imaging for On-Site Inspections

The purpose of an On-Site Inspection (OSI) is to determine whether a nuclear explosion has occurred in violation of the Comprehensive Nuclear Test Ban Treaty (CTBT), and to gather information which might assist in identifying the violator (CTBT, Article IV, Paragraph 35) Multi-Spectral and Infra Red Imaging (MSIR) is allowed by the treaty to detect observables which might help reduce the search area and thus expedite an OSI and make it more effective. MSIR is permitted from airborne measurements, and at and below the surface to search for anomalies and artifacts (CTBT, Protocol, Part II, Paragraph 69b). The three broad types of anomalies and artifacts MSIR is expected to be capable of observing are surface disturbances (disturbed earth, plant stress or anomalous surface materials), human artifacts (man-made roads, buildings and features), and thermal anomalies. The purpose of this Primer is to provide technical information on MSIR relevant to its use for OSI. It is expected that this information may be used for general background information, to inform decisions about the selection and testing of MSIR equipment, to develop operational guidance for MSIR use during an OSI, and to support the development of a training program for OSI Inspectors. References are provided so readers can pursue a topic in more detail than the summary information provided here. The following chapters will provide more information on how MSIR can support an OSI (Section 2), a short summary what Multi-Spectral Imaging and Infra Red Imaging is (Section 3), guidance from the CTBT regarding the use of MSIR (Section 4), and a description of several nuclear explosion scenarios (Section 5) and consequent observables (Section 6). The remaining sections focus on practical aspects of using MSIR for an OSI, such as specification and selection of MSIR equipment, operational considerations for deployment of MISR equipment from an aircraft, and the conduct of field exercises to mature MSIR for an OSI. Finally, an appendix provides detail describing the magnitude and spatial extent of the surface shock expected from an underground nuclear explosion. If there is a seismic event or other data to suggest there has been a nuclear explosion in violation of the CTBT, an OSI may be conducted to determine whether a nuclear explosion has occurred and to gather information which may be useful in identifying the party responsible for conducting the explosion. The OSI must be conducted in the area where the event that triggered the inspection request occurred, and the inspected area must not exceed 1,000 square kilometers, or be more than 50 km on aside (CTBT Protocol, Part II, Paragraphs 2 and 3). One of the guiding principles for an inspection is that it be effective, minimally intrusive, timely, and cost-effective [Hawkins, Feb 1998]. In that context, MSIR is one of several technologies that can be used during an aircraft overflight to identify ground regions of high interest in a timely and cost-effective manner. This allows for an optimized inspection on the ground. The primary purpose for MSIR is to identify artifacts and anomalies that might be associated with a nuclear explosion, and to use the location of those artifacts and anomalies to reduce the search area that must be inspected from the ground. The MSIR measurements can have additional utility. The multi-spectral measurements of the ground can be used for terrain classification, which can aid in geological characterization of the Inspected Area. In conditions of where light smoke or haze is present, long-wave infrared imaging can provide better imaging of the ground than is possible with standard visible imagery