This paper shows the experimental results and findings of field explosion tests conducted to obtainfundamental data concerning the explosion of hydrogen-air mixtures. A tent covered with thin plasticsheets was filled with hydrogen/air mixed gas, and subsequently ignited by an electric-spark orexplosives to induce deflagration and/or detonation. Several experiments with different concentrationsand/or volumes of mixture were carried out. The static overpressure of blast waves was measuredusing piezoelectric pressure sensors. The recorded data show that the shape of the pressure-timehistories of the resulting blast waves depends on the difference in the ignition method used. Thepictures of the explosion phenomenon (deflagration and/or detonation) were taken by high-speedcameras.