A surface or near-surface burst produces a hemispherical shock front that reflect from the ground. The reflected signal, traveling faster than the incident shock in the heated air. eventually overtakes the incident shock and forms a Mach stem that connects the ground with the triple intersection of incident, reflected, and Mach stem shocks. The dynamic movement of the air behind the Mach stem causes a second shock to form, producing double shock phenomena (36, 11, 10). The snapshot wave configuration sketched in Fig. 2.2 represents the phenomena
based on the following rationale.