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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  The 
  advance 
  of 
  the 
  flow 
  toward 
  Hilo 
  probably 
  stopped 
  on 
  May 
  5 
  

   or 
  6, 
  as 
  a 
  result 
  of 
  the 
  diversion 
  of 
  part 
  of 
  the 
  lava 
  by 
  the 
  new 
  flow 
  

   that 
  started 
  on 
  the 
  4th. 
  The 
  first 
  definite 
  confirmation 
  of 
  this 
  fact 
  

   came 
  when 
  H. 
  T. 
  Stearns 
  and 
  the 
  writer 
  crossed 
  the 
  flow 
  on 
  the 
  

   morning 
  of 
  May 
  7, 
  at 
  an 
  altitude 
  of 
  6,100 
  feet. 
  All 
  movement 
  had 
  

   then 
  ceased, 
  although 
  parts 
  of 
  the 
  flow 
  were 
  still 
  very 
  hot. 
  Red 
  

   glowing 
  lava 
  could 
  be 
  seen 
  in 
  many 
  places. 
  The 
  lava 
  was 
  nearly 
  all 
  

   aa, 
  but 
  a 
  few 
  small 
  tongues 
  of 
  pahoehoe 
  were 
  observed. 
  Accretionary 
  

   lava 
  balls, 
  formed 
  by 
  the 
  rolling 
  up 
  of 
  viscous 
  lava 
  about 
  some 
  

   solidified 
  center, 
  were 
  abundant. 
  13 
  Some 
  had 
  diameters 
  of 
  as 
  much 
  

   as 
  12 
  feet. 
  One 
  secondary 
  fumarole 
  was 
  observed, 
  consisting 
  of 
  a 
  

   hot 
  glowing 
  area 
  liberating 
  a 
  small 
  amount 
  of 
  sulfurous 
  fume, 
  and 
  

   encrusted 
  with 
  a 
  thin 
  deposit 
  of 
  sulfur. 
  This 
  secondary 
  fumarole 
  

   was 
  located 
  at 
  the 
  edge 
  of 
  one 
  of 
  the 
  dead 
  aa 
  rivers, 
  at 
  the 
  foot 
  of 
  

   the 
  levee, 
  and 
  the 
  edges 
  of 
  the 
  lava 
  rivers 
  were 
  generally 
  found 
  to 
  be 
  

   the 
  hottest 
  areas. 
  Organic 
  gases 
  such 
  as 
  methane 
  or 
  ammonia, 
  re- 
  

   sulting 
  from 
  the 
  partial 
  volatilization 
  of 
  vegetation 
  overflowed 
  by 
  

   the 
  lava, 
  were 
  not 
  observed, 
  but 
  were 
  probably 
  present 
  at 
  least 
  in 
  

   small 
  amounts 
  during 
  earlier 
  stages. 
  

  

  The 
  final 
  termination 
  of 
  the 
  lava 
  is 
  at 
  an 
  altitude 
  of 
  approximately 
  

   2,750 
  feet, 
  about 
  10 
  miles 
  from 
  the 
  center 
  of 
  Hilo. 
  The 
  total 
  length 
  

   of 
  the 
  flow 
  below 
  the 
  principal 
  lateral 
  vent 
  at 
  9,200 
  feet 
  altitude 
  is 
  

   approximately 
  16 
  miles. 
  

  

  BOMBING 
  OF 
  THE 
  LAVA 
  

  

  On 
  May 
  1, 
  there 
  apeared 
  to 
  be 
  imminent 
  danger 
  that 
  the 
  lava 
  flow 
  

   might 
  successively 
  cut 
  the 
  Olaa 
  flume 
  which 
  supplies 
  water 
  to 
  the 
  

   town 
  of 
  Mountain 
  View, 
  block 
  the 
  road 
  around 
  the 
  island, 
  and 
  de- 
  

   stroy 
  part 
  of 
  the 
  city 
  of 
  Hilo 
  and 
  the 
  Waiakea 
  plantation. 
  Con- 
  

   sequently, 
  the 
  United 
  States 
  Army 
  decided 
  to 
  try 
  to 
  divert 
  the 
  flow 
  

   by 
  aerial 
  bombing. 
  It 
  was 
  proposed 
  to 
  break 
  down 
  the 
  levees 
  and 
  

   allow 
  the 
  lava 
  river 
  to 
  escape 
  laterally, 
  thus 
  reducing 
  or 
  eliminating 
  

   the 
  supply 
  of 
  lava 
  to 
  the 
  main 
  front 
  of 
  the 
  flow. 
  R. 
  H. 
  Finch 
  made 
  

   a 
  reconnaissance 
  flight 
  and 
  selected 
  the 
  most 
  favorable 
  sites 
  for 
  

   bombing, 
  but 
  before 
  the 
  bombers 
  could 
  reach 
  the 
  area, 
  it 
  was 
  covered 
  

   by 
  clouds. 
  Therefore, 
  the 
  bombs 
  were 
  dropped 
  higher 
  up 
  the 
  flow 
  

   at 
  less 
  favorable 
  localities. 
  

  

  Altogether, 
  about 
  16 
  demolition 
  bombs 
  were 
  dropped, 
  some 
  weigh- 
  

   ing 
  300 
  and 
  others 
  600 
  pounds. 
  Most 
  struck 
  directly 
  on 
  the 
  target. 
  

   Some 
  bombs 
  were 
  dropped 
  on 
  the 
  lower 
  source, 
  but 
  without 
  appre- 
  

   ciable 
  effect. 
  The 
  others 
  were 
  dropped 
  at 
  a 
  place 
  where 
  the 
  open 
  

   lava 
  river 
  swung 
  against 
  the 
  outside 
  of 
  a 
  long 
  loop 
  in 
  its 
  course, 
  

  

  "These 
  have 
  been 
  termed 
  bombes 
  a 
  roulement, 
  but 
  the 
  name 
  is 
  Inappropriate. 
  Their 
  

   origin 
  is 
  not 
  at 
  all 
  like 
  that 
  of 
  true 
  volcanic 
  bombs. 
  

  

  