
330 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
Resulls of experiments in which composition of load and frequency of motion was varied. 


























Water: SAND = 20:80 WATER: SAND= 17:83 Water: SAND = 15:85 
Amplitude in Centimeters Amplitude in Centimeters Amplitude in Centimeters 
Frequency Frequency Frequency 
Car Block Car Block Car Block 
15) Out 9.5 6 6.0 7.9 9 6.1 6.3 
MS 6.1 9.7 1.0 6.0 8.5 ied 6.2 7.4 
1.0 6.1 9.5 1.4 6.0 9.0 2.6 6.4 8.1 
lea 6.1 9.2 6 6.1 9.3 3.3 6.5 8.4 
Lb 6.1 ee 2:0 6.1 9.5 3.6 6.3 8.0 
7a 6.2 5.9 2.4 6.1 (a5) 
ae 6.3 1.9 2.8 6.1 8.0 1.0 3.2 3.4 
3:0 6.4 3 3.6 6.4 4.4 1.2 3.3 3.8 
3.8 6.4 4.3 1.8 3.3 4.4 
.83 4.3 7.4 2.7 3.4 4.7 
1.0 4.3 Wien .85 ous 5.2 3.2 3.4 Dek 
13 4.3 6.5 1.5 3.3 5.3 3.9 3.4 6.2 
PAA 4.3 3.5 2.5 3.3 5.4 4.0 3.4 5.0 
3.0 4.3 2.4 3.1 3.4 4.3 4.6 3.6 5.5 
4.0 4.5 1.2 4.1 3.0 2.2 
























WATER: SAND = 12:88. La ihe = UN 4 t aces Dry GRAVEL. Wet GRAVEL. 
Amplitude in Cen- Amplitude in Cen- Amplitude in Cen- Amplitude in Cen- 
timeters B timeters timeters timeters 
Fre- Fre- 
Frequency quency quency 
Car Block Car Block Car Block Block 
1.8 6.2 6.3 1.4 4.4 4.5. 2.5 4.6 4.6 1.9 
2:5 6.4 6.4 2.0 4.7 6.3 2.8 4.6 4.9 20 
2.8 6.2 6.4 Bid 47 6.4 3.2 4.7 52 3.2 
3.2 6.7 7.0 2.5 4.7 6.5 3.3 4.8 5.4 3.4 
2.6 4.6 6.0 3.0 4.8 5.4 3.0 
1.0 3.1 3.1 2.6 4.8 5.5 San, 4.8 5.0 3.4 
1.8 3.2 3.2 3.2 4.7 3.8 3.8 4.9 5.2 3.4 
3.3 3.3 3.4 3.4 3.8 3.9 4.8 a5 
Bye) 3.4 Bsr 
4.0 3.4 3.8 
4.2 ane 3.8 

on the one hand from the soft and semi-fluid condition with a larger per cent of water, 
and on the other hand from a more friable condition with a smaller per cent of water. 
When the load contained only 12 per cent of water, the motion of the block embedded 
in the sand was very nearly the same as that of the car. For the data given, the motion 
of the block for the higher frequencies was slightly but unmistakably greater than the 
motion of the car. At another time, when there was about the same per cent of water 
in the sand, the motion of the sand was just as unmistakably less than that of the car, 
altho by only a small amount. In the latter case the sand was probably somewhat 
drier and less adhesive than in the former case. In still another experiment, in which 
the sand was very much drier, containing probably less than 5 per cent of water, the 
amplitude of the motion of the block was distinctly greater than that of the car, at least 
for frequencies of 3 per second. Of course this does not refer to the motion of the loose 
sand on top. The motion of a layer 1 or 2 em. deep of such loose, dry material was 
always much less than the motion of the car. 
In the above discussion we have been solely concerned with the motion of the block 
embedded in the sand in the middle of the car. The sand on the bottom and near the 
ends of the car has but little relative motion with respect to the car. A board thrust 
downward into the sand showed by its motion that the relative motion of the sand with 
