Explosions near the Earth’s surface excite both atmospheric overpressure and seismic ground motions. The amplitudes of air-blast (and hence acoustic/infrasound) overpressures and seismic motions depend on the explosive yield as well as the height-of-burst (HOB, for above ground emplacement) or depth-of-burial (DOB, for buried emplacement). We present analysis of air-blast overpressures and seismic motions with the goal of developing methods for robust yield estimation for near-surface blasts. Our investigations are based on the HUMBLE REDWOOD set of chemical high-explosive tests at Kirkland Air Force Base in Albuquerque, NM. We find that the air-blast positive phase impulse and seismic P-wave zero-to-peak displacement amplitude are robust estimators of yield. An empirical model for the amplitudes as a function of yield, range and HOB/DOB is presented and allows estimation of yield and HOB/DOB given a set of air-blast and seismic measurements. We find that yield and HOB/DOB can be estimated simultaneously by combining air-blast and seismic measurements. Strong trade-offs between the amplitudes and the yield and HOB/DOB for a single measurement type inhibit accurate estimates. However, simultaneous inversion of both overpressure and seismic measurements improve estimates, justifying combined seismo-acoustic analysis.