This project concerns tornado detection based on seismic waves. At the present time, the only generally accepted method for detecting when a tornado is on the ground is human observation. Based on actual seismic signals combined with eyewitness testimony, there is very strong evidence to indicate that a tornado in contact with the ground produces significant tornadic seismic vibrations (TSV), both long-period and short-period. The proposed program is designed to lead to a totally new way of detecting when a tornado is on the ground, based on the tornadic seismic signal (TSS) derived from the TSV. This seismic tornado detector (STD) system has considerable potential for use by government agencies for the protection of the general populace, as well as for use by the individual citizen for personal safety within the home. The specific research objective is to be accomplished during Phase 1 will be as follows: 1) Comparison of seismic records with tornado data to identify any additional chance measurements of TSS, 2) Continued collection of eyewitness accounts of TSV, 3) Improved understanding of the transfer of energy from the tornado to the ground, 4) Initial estimate of characteristics of TSS, 5) Design of STD instrument package, 6)Development of a test plan-for validation of STD system, and 7)Complete documentation of all results obtained.Commercial Applications:An STD alarm device could be marketed for use in private residences. In the twenty-two most tornado-prone states, where 91% of all tornadoes in the United States occur, there are an estimated 50 million residences. If 10% of the owners bought the product at a price between fifty and one hundred dollars, the market value would be 250 to 500 million dollars.