Many people, flying along the highway from Kona to Hawaii Volcanoes National Park, dash through South Hawaii as quickly as possible to reach the park without realizing they are missing some of the best, and least visited, places in the whole state. This southern end of the island is where the Polynesians first landed and began their colonization of the Hawaiian Islands; it is home to the beaches where most o the endangered green sea turtles breed and lay their eggs in the main Hawaiian chain, and it is home to some of the most amazing history and awesome history anywhere in the world…let’s take a few minutes and explore some of the fabulous and fantastic things to see and do along the Hawaii Belt Road through South Hawaii.
Mauna Loa South Flank Land Slides
The flanks of the Hawai’ian volcanoes are unusually unstable because of their extreme youth, rapid growth and because the flows are very thin, discontinuous and are comprised of loosely stacked a’a lava, air-fall material, pahoehoe lava with the loose rubble that forms when the lava flows into the sea. Because of this instability, many extremely large landslides in the past have broken loose, and this is the reason for the steep topography on the lower southern flanks of Mauna Loa. The angle of repose of Hawaiian lava flows (how steeply the land must tilt to get the lava to flow) is roughly 6 degrees, and looking at the gentle slopes of Mauna Kea and Mauna Loa, one sees that they come very close to this angle. Therefore, topography on the island that is steeper than about 6 degrees represents either faulting, erosion due to water movement or to landslides. One such twenty-mile long landslide, from about Mile 109 on Highway 11 to just north of Miloli’i, slid away about 120,000 years ago. One can see the scar from where the landslide broke loose along Kealakekua Bay and the precipitous cliffs that enfold the Captain Cook Monument as well as the steep hills of South Kona and northwest Ka’u. This landslide generated a tsunami wave of sufficient height to completely wash over the 1427-foot tall summit of Kaho’olawe and wash high up on the mountains of Lana’i. Coral rubble deposited by this tsunami can be found to this day on top of Kaho’olawe and at altitudes in excess of 1000 feet on Lana’i.
Old Mamalahoa Highway
A scenic stretch of the old Mamalahoa senderismo en Highway between mileposts 88 and 86 offers a glimpse into what life in Old Hawai’i was like. This rough old road remnant rolls through macadamia orchard and wild countryside and is worth the detour. Driving this stretch of road, remember that to Island residents, the Hawai’i Belt Highway is relatively new; many people living in Hilo will tell you they haven’t been to Kona in 20 years or more because the road is just too hard to drive, you know they are remembering the old highway like this, as it used to be, not as it exists today.
Manuka State Park
An easy 1-2 hour stroll, a great place for a picnic or a break from driving The Belt Highway, Manuka State Natural Area Reserve and Manuka State Wayside Park lie between the 82 and 81 mile markers and offers the unique setting of both lush wet, and dry-land, forest. The arboretum around the parking lot was planted of native and trees first introduced during the 1930s to the 1950s. The hike, which circles through the forest to a pit crater, takes 1-2 hours and has well-marked nature points of interest along the way. The trail also winds over both newer and older lava flows, so it’s easy to see how the forest develops through stages as the lava ages and weathers. Although an easy walk, some of the footing is loose, so sturdy shoes should be worn; no water is available along the trail, so you should carry a quart per person. This also is a very pleasant place to observe some of Hawai’i’s unique forest birds at dawn and sunset. The cool, inviting and fragrant Wayside Park has ample parking, picnic tables, restrooms and water available. There is a small covered pavilion at which “by permit-only” camping is allowed.