Both inward slumping and outward ejecta sliding are inferred to have occurred in four 10-ton explosive cratering events in Gulf coastal plain sediments. These inferences result from a comparison of displacements obtained by integration of real-time velocity data from subsurface gauges with displacements based on post-shot surveys. The slumping did not occur immediately after crater excavation; it was delayed by more than 5 seconds but less than one day. This delay probably resulted from slow recompaction and resaturation of the ejecta and crater walls on a scale of minutes to hours after the excavation and attendant dilation of the media. Ejecta sliding, probably at a few meters per second, apparently moved concrete blocks on the surface up to 2 meters outward relative to gauges buried at the same initial range. The ejecta sliding was not uniform and may occasionally have included portions of the underlying ground.