﻿366 
  OLDHAM: 
  GREAT 
  EARTHQUAKE 
  OF 
  1897. 
  

  

  diminished 
  or 
  has 
  disappeared; 
  this 
  may 
  be 
  attributed 
  to 
  a 
  compression 
  of 
  ther 
  

   hills 
  in 
  a 
  meridional 
  direction, 
  for 
  the 
  next 
  east-west 
  side, 
  that 
  joining 
  Mosingi 
  

   to 
  Mun, 
  again 
  shows 
  an 
  extension 
  of 
  4*4 
  feet. 
  North 
  of 
  Mosingi 
  and 
  Mauther- 
  

   richan 
  the 
  sides 
  again 
  exhibit 
  a 
  marked 
  diminution 
  of 
  the 
  apparent 
  expansion, 
  but 
  

   the.distance 
  between 
  Mautherrichan 
  and 
  Laidera 
  has 
  increased 
  3*9 
  feet, 
  in 
  a 
  

   W. 
  by 
  N. 
  direction. 
  Beyond 
  this 
  the 
  changes 
  get 
  very 
  irregular, 
  and 
  it 
  is 
  

   impossible 
  to 
  say 
  how 
  far 
  they 
  may 
  be~due 
  to 
  change 
  in 
  the 
  assumed 
  fixed 
  base. 
  

  

  The 
  conclusion 
  pointed 
  to 
  in 
  the 
  last 
  two 
  paragraphs 
  comes 
  out 
  still 
  more 
  

   clearly 
  when 
  the 
  table 
  showing 
  the 
  displacements 
  of 
  the 
  stations 
  is 
  examined.. 
  

   In 
  this, 
  as 
  in 
  all 
  the 
  other 
  lists, 
  I 
  have 
  arranged 
  the 
  stations 
  in 
  order 
  from 
  south 
  

   to 
  north, 
  arranging 
  those 
  which 
  are 
  on 
  nearly 
  the 
  same 
  parallel 
  in 
  order 
  from 
  

   west 
  to 
  east. 
  It 
  will 
  be 
  seen 
  from 
  this 
  that 
  the 
  apparent 
  displacements 
  of 
  the 
  

   three 
  stations 
  on 
  the 
  south 
  of 
  the 
  Khasi 
  hills 
  indicate 
  an 
  extension 
  of 
  5 
  and 
  

   6 
  feet 
  on 
  either 
  side 
  of 
  the 
  starting 
  point, 
  Rangsanobo, 
  Northwards 
  of 
  these, 
  the 
  

   displacements 
  decrease 
  in 
  a 
  marked 
  manner 
  till 
  we 
  reach 
  Mautherrichan 
  and 
  

   Dinghei, 
  to 
  the 
  north 
  of 
  which 
  they 
  increase 
  conspicuously. 
  

  

  The 
  true 
  explanation 
  of 
  these 
  facts 
  I 
  take 
  to 
  be, 
  that 
  the 
  assumed 
  value 
  of 
  the 
  

   base 
  Rangsanobo 
  — 
  Taramun 
  Tila 
  was 
  in 
  excess 
  of 
  the 
  real 
  value. 
  This 
  led 
  to 
  an 
  

   apparent 
  increase 
  in 
  all 
  other 
  sides 
  which, 
  so 
  far 
  as 
  the 
  calculations 
  go, 
  would 
  be 
  

   cumulative 
  and 
  lead 
  to 
  an 
  apparent 
  expansion 
  of 
  the 
  whole 
  chain 
  of 
  triangles- 
  

   Northwards 
  of 
  Rangsanobo, 
  however, 
  this 
  apparent 
  expansion 
  was 
  masked 
  by 
  

   an 
  actual 
  compression 
  of 
  the 
  country 
  as 
  a 
  whole, 
  a 
  compression 
  which 
  was 
  not* 
  

   however, 
  sufficient 
  to 
  reverse 
  the 
  apparent 
  effect 
  of 
  the 
  change 
  in 
  the 
  base 
  line.. 
  

   Northwards 
  of 
  Mautherrichan 
  and 
  Dinghei 
  the 
  compression 
  appears 
  to 
  die 
  out 
  

   and 
  the 
  cumulative 
  effect 
  of 
  the 
  error 
  of 
  the 
  original 
  base 
  becomes 
  conspicuous 
  

   once 
  more. 
  

  

  Another 
  point 
  to 
  notice 
  is 
  that 
  a 
  distinct 
  increase 
  in 
  the 
  compression 
  is 
  

   suggested 
  as 
  we 
  go 
  southwards. 
  Towards 
  the 
  northern 
  limit 
  of 
  the 
  triangulation 
  

   its 
  effect 
  is 
  small. 
  Between 
  the 
  latitudes 
  of 
  Mosingi 
  and 
  Mautherrichan 
  it 
  becomes 
  

   more 
  noticeable, 
  and 
  still 
  more 
  so 
  between 
  Mosingi 
  — 
  Mun 
  and 
  the 
  three 
  southern 
  

   stations 
  ; 
  the 
  compression 
  here 
  being 
  in 
  two 
  cases 
  sufficient 
  to 
  completely 
  counteract 
  

   the 
  apparent 
  expansion. 
  It 
  is 
  b}' 
  no 
  means 
  impossible 
  that 
  the 
  compression 
  was 
  

   greater 
  still 
  further 
  south, 
  and 
  reached 
  its 
  maximum 
  at 
  the 
  southern 
  limit 
  of 
  the 
  

   Khasi 
  hills, 
  so 
  that 
  the 
  assumed 
  unchanged 
  base 
  may 
  have 
  really 
  suffered 
  a 
  

   greater 
  actual 
  change 
  than 
  any 
  of 
  the 
  other 
  sides. 
  

  

  We 
  have 
  seen 
  that 
  a 
  detailed 
  examination 
  of 
  the 
  apparent 
  expansion 
  of 
  these 
  

   hills 
  is 
  consistent 
  with 
  a 
  real 
  compression 
  and 
  a 
  shortening 
  of 
  the 
  initial 
  base. 
  It 
  

   is 
  also 
  indubitable 
  that 
  such 
  compression 
  is 
  consistent, 
  not 
  only 
  with 
  what 
  is 
  known 
  

   generally 
  of 
  the 
  causes 
  of 
  great 
  earthquakes, 
  but 
  also 
  and 
  more 
  particularly 
  with 
  

   the 
  conclusion 
  come 
  to, 
  on 
  independent 
  grounds, 
  as 
  to 
  the 
  cause 
  of 
  this 
  particular 
  

   earthquake, 
  while 
  a 
  real 
  extension 
  of 
  the 
  hills 
  would 
  be 
  very 
  difficult 
  to 
  reconcile 
  

   with 
  that 
  explanation. 
  Putting 
  these 
  two 
  considerations 
  together 
  the 
  conclusion 
  

   may 
  be 
  adopted 
  that 
  the 
  Khasi 
  hills 
  were 
  not 
  extended 
  but 
  compressed 
  in 
  a 
  

   north 
  and 
  south 
  direction, 
  and 
  that 
  the 
  apparent 
  extension 
  was 
  due 
  to 
  a 
  realf 
  but 
  

   unnoticed, 
  contraction 
  of 
  the 
  assumed 
  initial 
  base. 
  

  

  ( 
  366 
  ; 
  

  

  