292 
PACIFIC SCIENCE, VoL XIX, July 1965 
TABLE 1 
Elastic Properties of Some Hawaiian Basalts 
SAMPLE 
v P * 
km / sec 
v s 
km/ sec 
e 
(DENSITY) 
g/cc 
K 
(BULK 
MODULUS) 
dynes/cm 2 
X io - 11 
g 
(MODULUS 
OF 
RIGIDITY) 
dynes /cm 2 
x io - 11 
F- 
(young’s 
modulus) 
dynes /cm 2 
x io 11 
K 
V 
a 
(POIS- 
SON’S 
RATIO) 
Olivine basalt 
4.95 
2.56 
2.0 
3.15 
1.31 
3.45 
2.40 
0.317 
4.63 
4.82 
Olivine basalt 
4.65 
2.50 
2.30 
3.05 
1.47 
3.80 
2.07 
0.292 
Olivine basalt 
5.65 
4.38 
3.10 
2.36 
4.03 
2.27 
5.23 
1.78 
0.264 
5.47 
Olivine basalt 
5.08 
3.02 
2.40 
4.6 
2.18 
5.56 
2.11 
0.296 
(ankaramite) 
Olivine basalt 
5.52 
2.76 
2.60 
5.27 
1.98 
5.27 
2.63 
0.330 
Eclogite 
6.06 
5.82 
2.94 
2.81 
6.29 
2.43 
6.45 
2.59 
0.328 
5.86 
Amphibolite 
6.90 
6.75 
3.53 
2.95 
8.5 
3.67 
9.63 
2.32 
0.312 
6.76 
Hawaiite 
4.20 
2.51 
2.59 
2.4 
1.63 
4.0 
1.48 
0.224 
Trachyte 
5.18 
2.83 
2.60 
4.22 
2.08 
5.4 
2.15 
0.298 
* The three values of Vp are for transmission in three mutually perpendicular directions of propagation through the same 
specimen. 
Figure 1 shows the velocity-density relation 
of the Hawaiian basalts and other volcanic 
rocks. These are primarily olivine basalts with 
varying amounts of olivine and other ferro- 
magnesian silicates. The velocities of the olivine 
basalts vary from 4.5— 6.5 km/sec with corre- 
sponding changes in densities from 2. 2-2. 8 
gm/cc. As will be seen, the values are largely 
dependent on vesicular structure, the amount 
of interstitial glass present, and the amount of 
olivine present. 
Figure 2 shows the variation in ultrasonic 
velocities in four olivine basalts of comparable 
density but having different percentages of oliv- 
ine. The inclusions of dunites and olivine-rich 
rocks in some of the volcanic flows on the island 
of Hawaii, especially in the 1801 flow, are not 
uncommon, and have been described by Ross 
et al. (1954). These rocks, composed princi- 
pally of olivine, give velocities of 65-12 
km/sec (density 2.8-3. 1 gm/cc) under atmos- 
pheric conditions of temperature and pressure. 
Of all the Hawaiian rocks whose transmission 
velocities have been measured (including eclo- 
gite), the dunites and olivine-rich inclusions 
give the highest values. The measured seismic 
velocities of the upper mantle under the Ha- 
waiian Archipelago (Furumoto and Woollard, 
p. 315 in this issue; Eaton, 1962) are of the 
order of 8.2-9.0 km/sec. Eaton’s deduced veloc- 
ity distribution under a typical volcano is based 
upon local earthquake data on Hawaii. The val- 
ues reported by Furumoto et al. are based upon 
explosion seismic refraction measurements. In- 
