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PHYSICAL GEOLOGY 



fault on either side. " The rate of diminution, with the exceptions 

 to be mentioned presently, may be expressed by saying that at five 

 miles from the fault only a few men and animals were shaken from 

 their feet, only a few wooden houses were moved from their founda- 

 tions, about half the brick chimneys remained sound and in condition 

 for use, sound trees were not broken, and no cracks were opened which 

 did not immediately close. At a distance of twenty miles only an 

 occasional chimney was overturned, the walls of some brick build- 

 ings were cracked, and wooden buildings escaped without injury; 



Fig. 274. — The slipping of alluvial soil toward the Salinas River, as a result 

 of the San Francisco earthquake. 



the ground was not cracked, landslides were rare, and not all sleepers 

 were wakened. At seventy-five miles the shock was observed by 

 nearly all persons awake at the time, but there were no destructive 

 effects ; and at two hundred miles it was perceived by only a few 

 persons." l The exceptions to the gradual diminution of intensity 

 occurred on the artificially filled or " made " land in the city, and 

 where there were tracts of deep alluvial soil, especially where ground 

 of this character was saturated with water (Fig. 274). Such ground 

 behaved during the earthquake very much like " jelly in a bowl," 

 the sudden shock causing it to be thrown into waves. 



1 G. K. Gilbert. 



