Kona Earthquake — MACDONALD AND WENTWORTH 
271 
EXPLANATION 
X Approximate epicenter of major 
earthquake 
X Epicenter of aftershock 
m Village 
fi Church 
1 Church with cemetery 
A Temple with cemetery 
o Cemetery 
j School 
^ Road 
Fault, buried 
Fault, suspected 
Lava flows of 1950 
Contour interval 1,000 feet 
0 5 miles 
Fig. 1, Map of the central Kona district showing the location of places mentioned in the text and the approx- 
imate locations of the epicenters of the major earthquake of August 21, 1951, and of the aftershocks for which 
reasonably good locations were obtained. The inset map of the island of Hawaii shows the location of the area 
(shaded) covered by the other map and the approximate position of the isoseismal lines for the major earthquake. 
Caldera were dismantled by the preliminary 
waves. Precise time control and, consequent- 
ly, the precise time of arrival of the first waves 
are lacking on the Kona and Hilo instruments. 
As a result, instrumental data are inadequate 
for the close location of the focus of the 
earthquake. The duration of the preliminary 
waves on the north-south component of the 
Bosch-Omori instrument was 9.5 seconds, 
corresponding with a distance of approxi- 
mately 47 miles from the Whitney Laboratory 
to the origin of the quake. 
John C. Forbes, instrument maker at the 
Volcano Observatory, repaired the minor 
