Structure of Koolau Volcano — Furumoto, Thompson, and Woollard 
311 
There is an offset in the Kailua recording of 
the 7.16 .km/sec line. Whether this is due to 
faulting is not certain. 
For the layer just below the water a velocity 
of 3.0 km/sec has been assigned. This assump- 
tion is based on the data from Chinaman’s Hat. 
Calculations from the travel-time data yielded 
the following: 
Layer 
Velocity 
Km to Top of Layer 
(km/sec) 
Kahuku Chinaman’s 
Hat 
a 
3.0 
0 
0 
b 
4.17 
1.2 
0.7 
c 
5.71 
3.8 
1.7 
d 
7.6 
5.4 
(Dipping 2° to NW) 
On the southern portion of the recording at 
Kailua High School station the velocity of 7.38 
km/sec appears as second arrivals. When this 
value was paired with the 8.17 of the Kahuku 
recording, we obtained 7.7 km/sec for layer d; 
11 km/sec was then assigned to layer d for the 
southern portion of the structure. 
A section structure for the able and K-K 
series is given in Figure 7. Notice the consistent 
lateral variation in velocities; the lower veloci- 
ties are in the northern section although the 
layers are deeper. 
The Southern Flank 
For the BRAVO series to the south of the 
island of Oahu recording units were set up at 
Barbers Point on Oahu and at Kualapuu on 
the adjacent island of Molokai (Fig. 1). Dis- 
tance between the recording units was 109 km. 
Because of inclement weather, the shots could 
be set off only in the protected lee of the island 
of Oahu. 
The travel-time plots of the BRAVO series are 
given in Figure 8. The upper set of lines rep- 
Fig. 6. Travel time plots of K-K and ABLE series. 
