﻿fi4 
  

  

  OLDHAM: 
  GREAT 
  EARTHQUAKE 
  OF 
  1897. 
  

  

  merits 
  of 
  other 
  stations, 
  which 
  seems 
  worth 
  publication, 
  though 
  the 
  data 
  were 
  less 
  

   complete 
  and 
  the 
  calculations 
  less 
  rigorous 
  than 
  in 
  the 
  case 
  of 
  those 
  printed 
  in 
  

   Major 
  Burrard's 
  report. 
  

  

  Changes 
  in 
  height 
  and 
  position 
  of 
  Secondary 
  Stations, 
  

  

  Station. 
  

  

  Suair 
  . 
  

   Rableng 
  . 
  

   Shillong 
  . 
  

   Somullon 
  

   Laitbli 
  . 
  

   Mairang 
  . 
  

   Kollong 
  Rock 
  

   Sniangf 
  . 
  

  

  Alteration 
  in 
  

  

  Height. 
  

  

  Ft. 
  

  

  Position. 
  

  

  Ft. 
  

  

  + 
  

  

  2-6 
  

  

  7'i 
  

  

  N 
  

  

  + 
  

  

  2*7 
  

  

  7'i 
  

  

  N 
  

  

  + 
  

  

  4*2 
  

  

  7'i 
  

  

  N 
  

  

  + 
  

  

  5-5 
  

  

  10-3 
  

  

  N 
  

  

  + 
  

  

  9'o 
  

  

  2-1 
  

  

  NE 
  

  

  + 
  IO-8 
  

  

  J 
  

  

  ? 
  

  

  + 
  I4'4 
  

  

  5'6 
  

  

  W 
  

  

  

  > 
  

  

  9-2 
  

  

  W 
  

  

  Direction. 
  

  

  A 
  cursory 
  inspection 
  of 
  these 
  tables 
  shows 
  that 
  there 
  have 
  been 
  differential 
  

   movements 
  of 
  the 
  stations, 
  with 
  respect 
  to 
  each 
  other, 
  which 
  are 
  too 
  large 
  and 
  too 
  

   irregular 
  to 
  allow 
  of 
  their 
  being 
  attributed 
  to 
  errors 
  of 
  observation. 
  The 
  tabulated 
  

   displacements 
  appear 
  also, 
  at 
  first 
  sight, 
  to 
  indicate 
  that 
  there 
  has 
  been 
  a 
  general 
  

   elevation 
  and 
  extension 
  of 
  the 
  hills, 
  such 
  as 
  might 
  follow 
  on 
  a 
  bulging 
  upwards 
  

   of 
  the 
  surface 
  due 
  to 
  the 
  intrusion 
  of 
  a 
  large 
  mass 
  of 
  molten 
  matter 
  underground. 
  

   A 
  more 
  detailed 
  examination, 
  as 
  will 
  be 
  shown, 
  does 
  not 
  bear 
  out 
  this 
  conclusion. 
  

  

  In 
  starting 
  any 
  calculation, 
  it 
  was 
  necessary 
  to 
  assume 
  one 
  side 
  of 
  one 
  triangle 
  

  

  unaltered 
  and 
  accept 
  this 
  as 
  a 
  base 
  ; 
  but 
  it 
  is 
  clear 
  that 
  within 
  the 
  area 
  over 
  

  

  which 
  the 
  triangulation 
  spread 
  no 
  single 
  side 
  was 
  left 
  unaltered 
  and 
  there 
  is 
  

  

  consequently 
  no 
  fixed 
  base 
  to 
  start 
  from. 
  To 
  quote 
  Major 
  Burrard's 
  report. 
  — 
  

  

  " 
  The 
  above 
  results 
  go 
  to 
  show 
  that 
  all 
  Mr. 
  Bond's 
  triangulation 
  lay 
  within 
  

  

  the 
  area 
  affected 
  by 
  the 
  earthquake 
  : 
  no 
  reliable 
  base 
  is 
  consequently 
  

  

  forthcoming 
  for 
  the 
  computation 
  of 
  his 
  observation. 
  Whatever 
  side 
  or 
  

  

  height 
  we 
  start 
  from, 
  we 
  find 
  that 
  all 
  other 
  sides 
  and 
  heights 
  have 
  altered, 
  

  

  but 
  the 
  errors 
  of 
  our 
  initial 
  side 
  and 
  height 
  pervade 
  the 
  calculations, 
  and 
  

  

  the 
  movements 
  caused 
  by 
  the 
  earthquake 
  are 
  given 
  differently 
  whenever 
  

  

  we 
  change 
  our 
  basis, 
  

  

  ( 
  364 
  ) 
  

  

  