A two dimensional seismic array was established in April 1974 at Haneda in Tokyo. The array covers a straight line of 2500 meter length. The former part of the
present report covers description of the seismic array and basic processing of the array records, which will serve as a basis for not only present report but also the second and the following reports.
　The latter part of the report covers analysis of array records for small earthquake (M=4.6) of which hypocenter was located at 60 km deep and 25 km away from Haneda. The analysis supports applicability of multiple reflection theory. The analysis showed a possibility that the seismic wave propagation model considered in the present report is effective for calculating difference in arrival time of incident waves to the base. The analysis also showed incident waves are not similar in wave from nor amplitude at adjacent points on the base.