Estimation algorithms are needed to estimate the damage situation in large-scale natural disasters from observed information that is often insufficient. Are the estimation algorithms applicable for disaster management? This is a serious question for those of us involved in a national Japanese research project known as “research and development of techniques about use and application of real-time information in the G-space platform.” In this paper, we present an experimental demonstration as our final evaluation of this project. We developed an integrated demonstration system implementing people number estimation using cell-phone connection logs and simulation data search using small amounts of real-time data to confirm usability. The virtual disastrous scenario set for the demonstration was a huge M7.3 earthquake that hits Tokyo. The demonstration system was presented to 39 participants (including 26 government officers and 13 university/industry experts) from 13 organizations on Jan. 27–28, 2016 for review. We sent a questionnaire to all participants afterward and nine organizations responded. In total, seven organizations responded with “Yes” to the question about whether our techniques were applicable for disaster management, thus confirming the effectiveness of the developed techniques.