260 
PACIFIC SCIENCE, Vol. XII, July, 1958 
156 ° 155 ® 
Fig. 1 . Map of the island of Hawaii, showing the location of the city of Hilo, and of barriers proposed to protect 
it from lava flows originating on the northeast rift zone of Mauna Loa. 
more than 1,000,000,000 cubic yards. Of these, 
7 flows have advanced toward Hilo, and in 
1881 lava actually invaded part of the present 
city. The volume of the 1881 flow toward 
Hilo was approximately 250,000,000 cubic 
yards. In 1942, a flow with a volume of ap- 
proximately 100,000,000 cubic yards started 
from a vent at 9,200 feet altitude and ad- 
vanced northeastward 16 miles, coming to a 
halt 12 miles from the shore of Hilo Bay. As 
compared with these flows from the northeast 
rift zone, the 1859 flow on the northwest 
slope of the mountain and the 1950 flows 
from the southwest rift zone each had a vol- 
