An excavation at Higashi-cho Site carried out in 1991 showed many faults, cracks, and traces of liquefaction resulting from the Great Kanto Earthquake of 1923 (Figs. 1-3). The site is situated beside the Sagami River where natural levees and backmarshes are interlocked in a complicated way. Part of the backmarsh had been filled artificially to the level of the natural levee.
The investigation can be summarized as follows;
(1) A number of faults and cracks appeared under the soil scorched by the fire that accompanied the 1923 Kanto Earthquake (Fig. 3), and a vein of quicksand stuck out of the liquefacted layers 1.2m deep in Trenches A and B dug in buried backmarshes (Fig. 4-6, (15)a, (15)b, (16), (17)).
(2) The hardpan ((4)), which was on the surface when the earthquake occurred, was displaced by faults. When the hardpan began to be covered with pieces of roof tile and mortar ((3)b) that fell from storehouses, quicksand might have erupted through the fault.
(3) The liquefacted layers ((15)-(17)) consist of fine sand and coarse silt (3-5_??_) (Fig. 7), covered with flood deposits (sand and gravel).
(4) The natural levee is covered with volcanic ash (air-fall deposit; Photo 2, (18)), which includes many pieces of pottery from the Yayoi period (about 1800 y. B. P.). There are no liquefacted layers in Trench C dug in the natural levee.
(5) According to those who experienced this earthquake, the liquefaction took place in and around the site.
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