Relationship between Soil Amplification Characteristics and Building Damage Distribution in Tokyo Lowland during the Kanto Earthquake

Abstract

The 1923 Great Kanto Earthquake destroyed many wooden buildings in Tokyo lowland in eastern Tokyo. The seismic intensity was estimated from the number of collapsed buildings in each area, and large differences were observed depending on the location, possibly due to differences in the soil amplification characteristics of seismic motions. A surface soil model for the Tokyo lowland around the Sumida River was developed with a three-dimensional grid model method based on borehole data. Based on microtremor measurements and seismic observation records, a method to estimate the S-wave velocity structure of the surface soil with higher accuracy was investigated to validate the grid models. The models were used in a seismic response analysis. The estimated SI values show good agreement with the distribution of damage to wooden buildings in the Taisho Kanto Earthquake, suggesting that the seismic amplification characteristics of the surface soil had a significant effect on the damage to buildings in the earthquake.