A Reconnaissance Gravity Survey of the Island of Kauai, Hawaii 1 
Harold L. Krxvoy , 2 Melville Baker, Jr., and Eugene E, Moe 3 
ABSTRACT: A large Bouguer anomaly on Kauai, similar to anomalies found at 
most of the other major volcanoes of the Hawaiian Islands, lies about 10 miles east 
of the caldera indicated by geologic mapping. Another gravity high suggests a sec- 
ond center of volcanism just west of the Island. 
Average Bouguer values on Kauai are higher than on other Hawaiian islands, 
indicating either that the crust beneath Kauai is 1-2 km thinner than It is beneath 
the eastern part of the Hawaiian Chain, or that the zone of increased density in the 
dike complex lies closer to the surface at 
islands of the chain. 
Between the 26th and 30th of May, 1963 
the authors carried out a reconnaissance gravity 
survey of the island of Kauai in Hawaii. Sta- 
tions occupied are shown in Figure 1, a general- 
ized topographic map of Kauai. A large part 
of Kauai is rugged and inaccessible, and in the 
course of this preliminary survey most avail- 
able roads were traversed. A more complete pic- 
ture of the gravity field of Kauai must await 
further penetration of the island with meters 
carried by helicopters-,- boats, and ground parties. 
The present gravity survey was planned to 
take advantage of the availability of a LaCoste 
and Romberg geodetic gravity meter and of re- 
cently completed topographic mapping on 
Kauai. The results are intended to supply a 
general idea of the local gravity configuration 
on Kauai, to permit comparison of the gravity 
field on Kauai with that on other islands of 
the state of Hawaii, and to serve as a guide 
for further investigations. 
OPERATIONAL DETAILS 
The Kauai gravity net was carried from 
bases on Hawaii, Maui, and Oahu. A new pri- 
mary base was established at Lihue Airport; 
the instrument was read directly in the center 
of a rectangular cement pad used by the U. S. 
Weather Bureau as a theodolite base. This pad 
is between the airport terminal building and 
1 Publication authorized by the Director, U. S. Geo- 
logical Survey. 
2 U. S. Geological Survey, Denver, Colorado. 
3 U. S. Geological Survey, Kauai, Hawaii. 
Kauai than do similar cores within other 
the weather dome. A secondary base was estab- 
lished on the ground near the front steps of 
the Lani Motel in Lihue. Tentative base values, 
tied to G. P. Woollard’s base (personal com- 
munication) at the old International Air Ter- 
minal, Oahu, are as follows: 
STATION 
GBV 
Lani Motel 
979,044.3 
Lihue Airport 
979,037.2 
Table 1 lists repeat readings made at Lani 
Motel during this survey. The negligible diur- 
nal drift, as well as the small total drift in the 
5 -day period, provide confidence for the zero- 
drift treatment accorded data collected in any 
single day. The repeat readings in Table 1 have 
been corrected for tidal attraction according to 
Goguel (1962). 
The table of principal facts is reported else- 
where (Hawaii Inst. Geoph., 1965, Table 7). 
TABLE 1 
Repeat Readings Made at Lani Motel, 
Lihue, Kauai 
DATE 
TIME 
(HST) 
READINGS 
( mgal ) 
5/26/63 
18:28 
2690.66 
5/27/63 
07:16 
2690.64 
5/27/63 
20:27 
2690.69 
5/28/63 
07:09 
2690.77 
5/28/63 
20:00 
2690.60 
5/29/63 
07:35 
2690.75 
5/29/63 
19:37 
2690.74 
5/30/63 
08:10 
2690.75 
354 
