— 240 — 
Earthquakes. 
The number of earthquake records received was 2402, 
relating to 483 earthquakes. 
Two important earthquake periods occurred in the month 
of April on the Toba highland (Tapanoeli) Sumatra, and 
during September, October and November on Java. 
The severe earthquake of April Ist caused large damage 
along the coasts of Toba lake and in the valley of the Batang 
Toroe (Taroetoeng). The heaviest shocks seem to originate 
from the bottom of the south-western parts ofthe lake. 
A long earthquake shaked Java and the surrounding 
isles (from Kroe, Sumatra, to Soembawa) on September 11th, 
being the first of a long series of earthquakes up to December 
all along the coasts of Java. Some of these shocks have 
been fairly important, being felt all over the island. The 
epicentra being submarine the damage caused was small. 
Table 1 gives the monthly geographical distribution, 
whereas table II contains a complete list of all earthquakes 
recorded with the local time of observation, the number 
of records (Column 5), the intensity after Rossi FOREL (Col 6), 
and the number of shocks recorded (Col 7). The Remarks 
(Col 8) give records of rumblings. 
Table III gives the following particulars for a number of 
earthquakes: 
Column 1: the number of the quake in the Seismological 
Bulletin Batavia 1921. 
Column 2 and 3: date and time of occurrence at the 
epicentre (G.M.T.) 
Column 4: the district. 
Column 5 and 6: the probable epicentre, derived with the 
aid of the seismological bulletins of neighbouring stations. *) 
Column 6: radius of macroseismic area. 
Column 7: seismic stations registering the quake. 
1) The time tables made use of are those published in Mededeelingen 
en Verhandelingen No 7, Koninklijk Magnetisch en Meteorologisch 
Observatorium te Batavia; S. W. Vi „ On the Distribution of 
Earthquakes in the Netherlands East Indian Archipelago 1909—1919. 
With a Discussion of Time Tables, Batavia 1921 
