Characteristics of the subsurface soils are considered to be one of the causes of the tremendous damage in Mexico City due to the 1985 Michoacan Mexico earthquake. In order to estimate the distribution of the subsurface soils in a horizontal plane, profiles of the soil layers, and a discussion of the relationship between the damage and the ground conditions, the authors developed the database system for the subsurface zone in Mexico City which shows the distribution of the soils on the maps and in the vertical sections.
The database system is composed fundamentally of several subsystems: data input, analyses, retrieval, and graphic display. The whole system is managed on the microcomputer. The characterisic of this system is that the interpolation analysis for water content and soil names is included in the subsystem for analyses. Cluster analysis is provided for the prediction of vertical sections of subsurface soil layers. On the graphic display the distribution of soil name, N-value, and water content in the vertical direction can be retrieved along the arbitrary section which are pointed up on the cathode ray tube display.
Those results were applied for the prediction of the seismic intensity in Mexico City, and the analyzed earthquake motion coincided quite well with those recorded in the 1985 Mexico earthquake because of the proper estimation of subsurface soils. When a geographic information system is developed, this kind of examination of the system is important.