OHE March 28, 1998

Date: Sat, 28 Mar 1998 07:02:00 -1000
From: Nathan Yuen (nyuen@lava.net>
Subject: Rock Formations of Koko Crater

Went on a hike yesterday to explore the fascinating rock formations at Koko Crater, the horseshoe-shaped volcanic crater with an opening on its northeast side. Located at the eastern most tip of Oahu along the Kaiwi Coastline, Koko Crater is the highest and most prominent of the volcanic vents that are oriented in a northeasterly line which includes Koko Head, Hanauma Bay, Kahauloa Crater, Kalama Crater, Manana (Rabbit Island), and Kaohikaipu (Manana's low-lyng companion).

From my starting vantage point at Sandy Beach I could easily see the odd-looking dark-colored rock formations, sometimes called parasol ribbing, which appear to hang precariously off the edge of the crater rim. Made when the soft light-colored layer of volcanic tuff (welded ash) eroded away from beneath the harder dark-colored layer at the surface, these unusual ledge-like formations are found in many places along the crater.

Starting the hike above the tiny cove that is carved just behind Blow Hole, I was fortunate to be at Blow Hole at high-tide when waves crash the against the rocks, create pressure beneath the rocky ledge, and force plumes of mist out the hole high into the air! I particularly was pleased that I was able to catch a couple of shots of the blow hole in action. Whadda neat sight!

As I started my ascent up the small valley just opposite the cove, the many layers of volcanic tuff and the sparkle of olivine crystals were plainly visible. When I reached the end of the valley, the natural bridge off in the distance came into view. Since I hiked this trail before and had already climbed over the steep bridge, I decided to do something different and go through the hole in the arch instead. Taking a detour which paralleled the trail, I climbed up a slippery slope littered with the brittle remains of the light-colored soft rock which had eroded away over the passage of time to create the flying arch.

When I reached the arch, I noted that the large hole is oriented at an angle of what must be about 45 degrees and is about 30 feet long and 8 feet high. The dark-colored hard rock above the hole which forms the bridge is about 8 feet wide and 6 feet thick. After snapping several pictures of the flying arch and admiring the views from this neat place, I continued onward up the side of the crater.

As I reached the lip of the crater, strong gusts of wind greeted me. Blowing unexpectedly at times, I could not help but cling to the rocks at several of the more harrowing spots along the rim. As I continued along the trail, several interesting rock formations presented themselves along the rim. When I reached Pu'u Ma'i, the highest point on the crater, Hanauma Bay sparkled magnificently below in the sunlight as its shallow green, azure, and teal waters melded into the deep blue waters of the ocean. What a beautiful sight!

Continuing beyond to explore the side of the crater that overlooks Hawaii Kai, I climbed down a rocky precipice that turned into an incredibly narrow section. With the wind howling in my face, I lost my nerve and decided to turn back. Retracing my steps back to Pu'u Ma'i and continuing across the rim on the side that overlooks Sandy Beach, I descended down the side of the crater into the Botanical Garden.

As I trampled back through the dry grasses at the foot of Koko Crater and returned to Sandy Beach, I was pleased that I had braved the howling wind along the rim of the crater and that I had seen up close the neat rock formations of Koko Crater. Whadda neat experience!

P.S. If you wanna see some pictures of the unusual parasol ribbing rock formations, the cool natural bridge, and the incredible blue waters off Halona Point, Hanauma Bay, and the Kaiwi Channel, point your web browser to:


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