﻿280 
  Jaggar- 
  — 
  Lava 
  Flow 
  from 
  Mauna 
  Loa, 
  1916. 
  

  

  eruption 
  taking 
  place 
  still 
  farther 
  north 
  where 
  the 
  sulphur- 
  

   bearing 
  gas 
  could 
  make 
  its 
  deposit 
  along 
  a 
  crack 
  not 
  clogged 
  

   by 
  freshly 
  congealed 
  magma. 
  

  

  Pahoehoe 
  and 
  Aa 
  Lava. 
  

  

  The 
  moving 
  basaltic 
  lava 
  of 
  the 
  1916 
  outflow 
  was 
  aa, 
  or 
  

   block 
  lava, 
  away 
  from 
  the 
  vents 
  but 
  in 
  the 
  lava 
  stream 
  courses 
  

   close 
  to 
  the 
  rift 
  source 
  the 
  surface 
  had 
  the 
  ropy 
  and 
  mem- 
  

  

  Fig. 
  

  

  Fig. 
  7. 
  Detail 
  of 
  aa 
  lava, 
  Honomalino 
  flow, 
  showing 
  tendency 
  of 
  surface 
  

   rock 
  to 
  separate 
  into 
  endlessly 
  divisible 
  fragments. 
  Flames 
  in 
  crevices 
  

   when 
  picture 
  was 
  taken, 
  May 
  23, 
  1916. 
  Photo. 
  Colville. 
  

  

  braneous 
  character 
  of 
  a 
  coarsely 
  vesicular 
  pahoehoe. 
  The 
  

   transition 
  to 
  block 
  lava 
  took 
  place 
  along 
  the 
  course 
  of 
  the 
  flows 
  

   within 
  a 
  few 
  hundred 
  yards 
  of 
  the 
  source. 
  There 
  was 
  gaseous 
  

   explosion 
  ejecting 
  pumiceous 
  fragments 
  at 
  the 
  cones 
  until 
  the 
  

   end 
  of 
  the 
  eruption, 
  for 
  much 
  of 
  the 
  lava 
  is 
  there 
  buried 
  under 
  

   such 
  light 
  fragments. 
  

  

  The 
  aa 
  of 
  Kahuku 
  which 
  the 
  writer 
  saw 
  in 
  rapid 
  motion 
  on 
  

   May 
  2i 
  consolidated 
  into 
  finely 
  vesicular 
  fragments 
  of 
  light 
  

   weight, 
  but 
  that 
  of 
  Honomalino 
  was 
  largely 
  coarse, 
  heavy 
  and 
  

   lithoidal 
  (fig. 
  7). 
  The 
  specimens 
  of 
  pahoehoe 
  collected 
  near 
  

   the 
  source 
  during 
  activity 
  were 
  fresh 
  black 
  glistening 
  vitreous 
  

   basalt 
  of 
  a 
  very 
  foamy 
  or 
  sponge-like 
  consistency. 
  The 
  aa, 
  on 
  

  

  