MASINT (measurement and signature intelligence) is intelligence obtained from the detection and characterization of physical phenomena associated with targets: acoustic signatures, seismic disturbances, chemical traces, nuclear radiation, electromagnetic emissions, and other measurable properties. MASINT identifies what something is by how it behaves physically — the sound profile of a specific engine type, the chemical trace of an explosive compound, the seismic signature of underground construction, the infrared emission of a recently launched missile.
MASINT is distinguished from other technical collection disciplines by its focus on physical properties rather than communications (SIGINT) or visual appearance (IMINT). It operates across multiple domains: acoustic sensors detect submarines and artillery; seismic monitors identify underground nuclear tests; chemical detectors characterize weapons of mass destruction; spectral analysis identifies materials from reflected or emitted radiation; radar signatures distinguish between aircraft types.
The discipline is technically demanding and often requires specialized sensors deployed in proximity to the target. Its products tend to be highly specific — a confirmed chemical composition, a verified seismic event — but narrow in scope. MASINT rarely provides strategic context on its own; it gains value when fused with other collection disciplines to answer questions that imagery or signals collection cannot resolve independently.