﻿202 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  known 
  as 
  North 
  Bay, 
  which 
  adjoins 
  Mokuaweoweo 
  on 
  the 
  north. 
  It 
  

   was 
  first 
  reported 
  by 
  observers 
  about 
  6 
  p. 
  m., 
  but 
  the 
  seismograph 
  

   record 
  shows 
  that 
  it 
  actually 
  commenced 
  at 
  5 
  : 
  05 
  p. 
  m. 
  4 
  Lava 
  foun- 
  

   tains 
  played 
  along 
  the 
  fissure, 
  building 
  up 
  small 
  ramparts 
  of 
  spatter, 
  

   and 
  streams 
  of 
  molten 
  pahoehoe 
  5 
  cascaded 
  down 
  the 
  caldera 
  walls 
  

   forming 
  a 
  lava 
  flow 
  along 
  the 
  base 
  of 
  the 
  western 
  wall 
  and 
  around 
  the 
  

   west 
  and 
  north 
  edges 
  of 
  North 
  Bay. 
  Shortly 
  afterward 
  the 
  fissure 
  was 
  

   extended 
  on 
  down 
  the 
  northeastern 
  flank 
  of 
  the 
  mountain 
  for 
  a 
  dis- 
  

   tance 
  of 
  21/2 
  miles, 
  passing 
  close 
  to 
  the 
  south 
  edge 
  of 
  the 
  main 
  cone 
  

   of 
  the 
  1935 
  eruption. 
  Highly 
  fluid 
  lava 
  issued 
  from 
  the 
  fissure 
  along 
  

   its 
  entire 
  length. 
  Small 
  spatter 
  ramparts 
  were 
  built 
  in 
  places, 
  but 
  in 
  

   general 
  there 
  was 
  little 
  accumulation 
  of 
  spatter 
  along 
  the 
  fissure. 
  

   Much 
  of 
  the 
  early 
  lava 
  was 
  covered 
  with 
  a 
  pumiceous 
  top, 
  half 
  an 
  inch 
  

   to 
  over 
  an 
  inch 
  thick, 
  owing 
  to 
  the 
  extreme 
  vesiculation 
  of 
  the 
  gas-rich 
  

   magma. 
  The 
  lava 
  flow 
  streamed 
  northward 
  down 
  the 
  mountain 
  slope 
  

   toward 
  Mauna 
  Kea 
  for 
  several 
  miles, 
  dividing 
  into 
  two 
  major 
  lobes. 
  

   Pahoehoe 
  near 
  the 
  source 
  gave 
  place 
  to 
  aa 
  6 
  at 
  the 
  lower 
  ends 
  of 
  the 
  

   flow. 
  On 
  the 
  night 
  of 
  April 
  26 
  the 
  fume 
  column, 
  illuminated 
  by 
  glow 
  

   from 
  the 
  fountains 
  beneath, 
  was 
  clearly 
  visible 
  from 
  Kilauea, 
  rising 
  

   nearly 
  vertically 
  to 
  an 
  altitude 
  of 
  about 
  15,000 
  feet 
  and 
  then 
  drifting 
  

   southwestward. 
  

  

  At 
  2 
  a. 
  m., 
  April 
  27, 
  G. 
  O. 
  Fagerlund 
  and 
  B. 
  J. 
  Loucks, 
  of 
  Hawaii 
  

   National 
  Park, 
  began 
  the 
  ascent 
  of 
  the 
  mountain. 
  The 
  ground 
  was 
  

   quaking 
  continually, 
  averaging 
  three 
  or 
  four 
  distinct 
  shocks 
  a 
  minute. 
  

   On 
  reaching 
  the 
  rest 
  house 
  at 
  Puu 
  Ulaula, 
  at 
  an 
  altitude 
  of 
  10,000 
  feet, 
  

   the 
  shocks 
  appeared 
  to 
  originate 
  directly 
  beneath 
  their 
  feet, 
  and 
  a 
  

   crude 
  heavy 
  pendulum 
  set 
  up 
  by 
  Loucks 
  showed 
  almost 
  no 
  horizontal 
  

   displacement. 
  They 
  therefore 
  decided 
  to 
  remain 
  at 
  Puu 
  Ulaula 
  in- 
  

   stead 
  of 
  continuing 
  to 
  the 
  summit, 
  as 
  had 
  been 
  planned, 
  and 
  as 
  a 
  result 
  

   they 
  had 
  the 
  rare 
  privilege 
  of 
  witnessing 
  at 
  close 
  range 
  the 
  opening 
  

   phases 
  of 
  the 
  flank 
  eruption. 
  

  

  FLANK 
  ERUPTION 
  

  

  Opening 
  phase. 
  — 
  At 
  4:40 
  a. 
  m., 
  April 
  28, 
  molten 
  lava 
  broke 
  out 
  

   along 
  a 
  fissure 
  in 
  the 
  northeast 
  rift 
  zone 
  about 
  iy 
  2 
  miles 
  east-northeast 
  

   of 
  Puu 
  Ulaula 
  (fig. 
  1) 
  . 
  Fagerlund 
  and 
  Loucks 
  reached 
  the 
  site 
  of 
  the 
  

   eruption 
  at 
  7 
  : 
  30 
  a. 
  m. 
  At 
  that 
  time 
  a 
  nearly 
  continuous 
  sheet 
  of 
  lava 
  

   fountains 
  was 
  issuing 
  from 
  a 
  fissure 
  over 
  half 
  a 
  mile 
  in 
  length, 
  form- 
  

   ing 
  the 
  "curtain 
  of 
  fire" 
  frequently 
  observed 
  during 
  the 
  opening 
  

   stages 
  of 
  Mauna 
  Loa 
  eruptions. 
  The 
  fissure 
  extended 
  from 
  an 
  alti- 
  

   tude 
  of 
  about 
  9,500 
  to 
  9,200 
  feet, 
  with 
  a 
  trend 
  of 
  N. 
  85° 
  E. 
  The 
  foun- 
  

   tains 
  played 
  to 
  heights 
  of 
  200 
  to 
  300 
  feet 
  above 
  the 
  ground. 
  

  

  * 
  Finch, 
  R. 
  EL, 
  personal 
  communication. 
  

  

  E 
  Pahoehoe 
  = 
  lava 
  that 
  congeals 
  In 
  smooth, 
  sometimes 
  ropy 
  forms. 
  

  

  8 
  Aa=lava 
  with 
  a 
  rough, 
  clinkery 
  top. 
  

  

  