Today, we can see some of these rocks up close. Also, these are not as weathered as we saw previously. The lava flows are well preserved at Nu’uanu Pali park (Fig. 4).
This post visited the remains of the Ko’olau volcano, which exploded/collapsed/disappeared into the Pacific Ocean about 1.7 my, leaving a sharp mountain range that was the edge of the central caldera. A much younger tuff cone erupted about 100 thousand-years ago as part of the rejuvenation of the magma chamber. Its last gasp as it were.