Hawaii as a Site for the Moho Hole— WOOLLARD 
283 
chemical, and geologic information in the Ha- 
waiian area will permit a more intelligent analy- 
sis of the Moho Hole data than can be under- 
taken in almost any other area. 
Summary 
The arguments for locating the Moho Hole 
at Hawaii are all favorable from the practical 
viewpoint of bringing off a successful operation. 
This is extremely important from the stand- 
point of obtaining support for drilling other 
such holes elsewhere. Failure to drill to com- 
pletion— because of some natural catastrophe, 
such as a hurricane; the incurrence of higher 
than anticipated costs because of logistic sup- 
port problems over distances greater than that 
associated with the Hawaii site; delays caused 
by inferior local support— might well jeopardize 
future operations of this type. It is imperative, 
therefore, that the initial undertaking be made 
where possible adverse extraneous factors af- 
fecting the operation are minimized. Admit- 
tedly, the depth of drilling to the Moho off 
Hawaii is somewhat greater than that deter- 
mined off Antigua, but a technology capable 
of drilling to 8 km should be capable of drilling 
to 9 km equally as well. The difference in dollar 
costs is not regarded as significant, because the 
additional drilling costs off Hawaii will be off- 
set by savings in logistic and supply costs. 
From a scientific standpoint, there is no ques- 
tion regarding the superiority of Hawaii as a 
site for the Moho Hole. There are no indica- 
tions of faulting or other tectonic factors that 
might influence pressure and temperature rela- 
tions, and hence, the character of the mantle. 
Although the structure of the crust at the rec- 
ommended site is locally somewhat abnormal, 
this actually is a favorable circumstance in that 
drilling here 'would permit a second major sci- 
entific problem, the origin of the crust, to be 
investigated in an area where it is undergoing 
change. A third major scientific problem, the 
derivation of tholeiitic basalts, probably can be 
resolved by drilling off Hawaii. The drilling of 
a shallow hole to sample mantle-like material 
on Oahu would further add to the significance 
of the program and give valuable information 
on the chemical homogeneity of the mantle over 
a span of some 200 miles. Finally, the results 
can be integrated with those of related geo- 
logical, geochemical, and geophysical research 
programs that have been operating in Hawaii 
for a number of years, and which will be main- 
tained on a continuing and expanded basis, 
and thus contribute to the significance of the 
operation for many years to come. 
REFERENCES 
Bromery, R. W., and A. Griscom. 1964. A 
gravity survey in the Mayaguez area of south- 
west Puerto Rico. Nat. Acad. Sciences Publ. 
1188:61-74. 
Engel, A. E. J., and C G. Engel. 1964. Igne- 
ous rocks of the East Pacific Rise. Science 
146:477-485. 
Ewing, M., and F. Press. 1959. Determination 
of crustal structure from phase velocity of 
Rayleigh waves. Part 3: The Untited States. 
Bull. Geol. Soc. Am. 70:229-244. 
Hess, PI. H. 1955. Serpentine orogeny and 
epierogeny. In: The crust of the earth. Geol. 
Soc. Am., Sp. Paper 62:391-408. 
— — — 1955. The oceanic crust. J. Marine Re- 
search 14:423-439. 
1962. History of ocean basins. In: Pet- 
rologic Studies: A Volume to Honor A. F. 
Buddington, pp. 559-620. Geol. Soc. Am. 
1964. The oceanic crust, the upper 
mantle and the Mayaguez serpentinized perid- 
otite. In: A study of serpentine. Nat. Acad. 
Sciences Publ. 1188:169-175. 
Kennedy, G. 1959. The origin of continents, 
mountain ranges and ocean basins. Am. Sci- 
entist 47:494-504. 
Kuno, H. 1959. Origin of Cenozoic petro- 
graphic provinces of Japan and surrounding 
areas. Bull. Volcanol. 20:37-76. 
Meyer, R. P., J. Steinhart, and G. P. Wool- 
lard. 1958. Seismic determination of crustal 
structure in the central plateau of Mexico. 
Trans. Am. Geophys. Un. 39:525. 
Shor, G. G., and D. D. Pollard. 1964. Mohole 
site selection studies north of Maui. J. Geo- 
phys. Research 69: 1627-1637. 
