Lava Barrier at Hilo — WENTWORTH, POWERS, and EATON 
355 
Fig. 1 . Map of the vicinity of Hilo, Hawaii, showing historic and recent prehistoric lava flows from 
Mauna Loa that approached Hilo Bay. Shaded area represents present extent of the city of Hilo. 
an altitude of 6,800 ft. Even if it is assumed 
that the reasoning of Stearns and Macdonald is 
incorrect (and there is no compelling geologi- 
cal basis for such an assumption), and that the 
supposed branch of the rift zone does not exist, 
there remains strong geologic precedent for an 
outbreak through any flank area away from a 
known rift zone. Of the 72 known flank erup- 
tions, 18, or one-fourth, have broken through 
the mountain flank several miles away from 
any known rift zone. The eruption of 1877, 
above and in Kealakekua Bay (Hitchcock, 1909: 
115), broke out as far from a rift zone as it is 
possible to be. There has been no eruption, in 
