﻿ERUPTION 
  OF 
  MAUNA 
  LOA 
  — 
  MACDONALD 
  207 
  

  

  lava 
  river, 
  but 
  that 
  on 
  the 
  southern 
  side 
  formed 
  a 
  new 
  flow 
  which 
  

   advanced 
  down 
  the 
  mountain 
  for 
  a 
  distance 
  of 
  about 
  6 
  miles, 
  and 
  

   continued 
  flowing 
  until 
  May 
  7. 
  10 
  The 
  lowering 
  of 
  the 
  lava 
  level 
  in 
  

   the 
  cone 
  was 
  accompanied 
  by 
  a 
  temporary 
  increase 
  to 
  about 
  600 
  feet 
  

   in 
  the 
  height 
  of 
  the 
  fountains, 
  probably 
  owing 
  to 
  the 
  removal 
  of 
  part 
  

   of 
  the 
  damping 
  effect 
  of 
  the 
  ponded 
  lava 
  on 
  the 
  gases 
  rising 
  through 
  

   it. 
  This 
  new 
  flow 
  diverted 
  a 
  large 
  volume 
  of 
  lava 
  from 
  the 
  older 
  

   flow, 
  and 
  was 
  probably 
  largely 
  responsible 
  for 
  the 
  cessation 
  of 
  move- 
  

   ment 
  at 
  the 
  front 
  of 
  the 
  older 
  flow 
  which 
  occurred 
  on 
  May 
  5 
  or 
  6. 
  11 
  

  

  R. 
  H. 
  Finch 
  visited 
  the 
  fountains 
  on 
  May 
  5 
  and 
  6, 
  and 
  reported 
  that 
  

   two 
  flows 
  were 
  moving 
  eastward 
  from 
  the 
  cones. 
  Both 
  were 
  pahoehoe 
  

   for 
  over 
  half 
  a 
  mile 
  from 
  the 
  source 
  but 
  changed 
  to 
  aa 
  in 
  less 
  than 
  

   a 
  mile. 
  At 
  7,000 
  feet 
  altitude 
  the 
  new 
  lava 
  was 
  in 
  places 
  40 
  feet 
  

   thick. 
  

  

  On 
  the 
  morning 
  of 
  May 
  7, 
  Paul 
  and 
  Sarah 
  Baldwin, 
  of 
  Hawaii 
  

   National 
  Park, 
  witnessed 
  the 
  outbreak 
  of 
  two 
  more 
  small 
  flows 
  from 
  

   the 
  western 
  cone, 
  which 
  had 
  become 
  the 
  site 
  of 
  the 
  principal 
  fountain 
  

   activity. 
  The 
  first 
  flow 
  broke 
  from 
  the 
  south 
  side 
  of 
  the 
  cone 
  at 
  6 
  : 
  30 
  

   a. 
  m., 
  and 
  continued 
  for 
  less 
  than 
  half 
  an 
  hour, 
  forming 
  a 
  short 
  

   stream 
  of 
  aa. 
  At 
  7 
  a. 
  m. 
  the 
  second 
  flow 
  escaped 
  through 
  a 
  wall 
  of 
  

   the 
  cone 
  on 
  its 
  southwestern 
  side, 
  and 
  formed 
  a 
  short 
  pahoehoe 
  stream 
  

   along 
  the 
  south 
  base 
  of 
  the 
  cone 
  chain. 
  This 
  flow 
  did 
  not 
  escape 
  over 
  

   the 
  edge 
  of 
  the 
  cone, 
  but 
  forced 
  its 
  way 
  through 
  the 
  cone 
  wall, 
  ap- 
  

   pearing 
  first 
  as 
  a 
  slightly 
  glowing 
  bulge 
  which 
  slowly 
  distended 
  and 
  

   developed 
  into 
  a 
  stream 
  of 
  pahoehoe. 
  These 
  repeated 
  short 
  outflows 
  

   heaped 
  up 
  a 
  small 
  lava 
  dome 
  about 
  the 
  edges 
  of 
  the 
  cinder 
  and 
  spatter 
  

   cone, 
  burying 
  the 
  base 
  of 
  the 
  cone 
  to 
  a 
  depth 
  of 
  30 
  feet. 
  

  

  Declining 
  phase. 
  — 
  The 
  cones 
  were 
  again 
  visited 
  by 
  the 
  writer 
  on 
  

   May 
  9. 
  Activity 
  had 
  greatly 
  decreased, 
  and 
  was 
  restricted 
  to 
  two 
  

   small 
  fountains. 
  The 
  ejected 
  lava 
  was 
  a 
  deeper 
  red 
  than 
  during 
  

   the 
  previous 
  visit, 
  indicating 
  a 
  decrease 
  in 
  temperature. 
  The 
  larger 
  

   fountain 
  occupied 
  ;the 
  western 
  vent 
  of 
  the 
  cone 
  chain, 
  and 
  was 
  

   in 
  explosive 
  activity, 
  throwing 
  lava 
  clots 
  50 
  to 
  70 
  feet 
  above 
  the 
  

   cone, 
  but 
  with 
  no 
  true 
  jet 
  of 
  liquid 
  lava 
  visible. 
  The 
  smaller 
  foun- 
  

   tain 
  occupied 
  the 
  next 
  pit 
  to 
  the 
  east, 
  and 
  was 
  a 
  true 
  fountain 
  15 
  to 
  

   20 
  feet 
  high, 
  with 
  frequent 
  explosive 
  bursts 
  reaching 
  a 
  height 
  of 
  50 
  

   feet. 
  During 
  the 
  intervals 
  between 
  bursts, 
  a 
  jet 
  of 
  magma 
  could 
  be 
  

   seen 
  curving 
  obliquely 
  upward 
  from 
  one 
  side 
  of 
  the 
  pit 
  and 
  splashing 
  

   down 
  against 
  the 
  other 
  side. 
  A 
  lava 
  river 
  15 
  feet 
  wide 
  cascaded 
  

   rapidly 
  from 
  this 
  pit 
  and 
  flowed 
  sluggishly 
  off 
  (pi. 
  2, 
  fig. 
  1), 
  at 
  a 
  rate 
  

   of 
  about 
  half 
  a 
  mile 
  an 
  hour, 
  forming 
  a 
  ropy 
  crust 
  in 
  which 
  the 
  

   glowing 
  lava 
  beneath 
  could 
  be 
  seen 
  through 
  the 
  cracks. 
  The 
  lava 
  

  

  30 
  Finch, 
  R. 
  H., 
  press 
  release, 
  National 
  Park 
  Service, 
  U. 
  S. 
  Dep. 
  Interior, 
  May 
  23, 
  1942. 
  

   » 
  Finch, 
  R. 
  H., 
  op. 
  clt. 
  

  

  