Huge amount of tsunami deposits remain after the large earthquake and tsunami occurred on March 11, 2011. This event may bring a possibility of environmental pollutions, particularly in the environment of soil and sediments around coastal areas of eastern Japan. Therefore a geochemical survey and investigation for soil contamination risk was carried out, to make clear the risk level caused by tsunami event and its deposits. Samples of tsunami deposits were analyzed by means of chemical and physical methods to accumulate the database for evaluating the environmental risk. Various kinds of tsunami deposits were observed at the coastal areas, some of them are sandy sediments and others are muddy with much clay components. The result of chemical analysis showed that some portions of deposits contain a little higher content of arsenic and lead, however, almost are similar component compared with normal subsurface soils. In the analysis of physical properties of deposits, a series of database was developed for particle distribution, soil and clay components, and content of organic matters. An approach of statistical analysis of elements in tsunami deposits was conducted by using an original technic of sparse modeling, in which the discrimination between tsunami deposits and normal marine stratums has been investigated.