October 28, 2010
A weekly feature provided by scientists at the Hawaiian Volcano Observatory.
Kahuku: Where lava flows and cow pastures coexist
In 2003, almost two-thirds of the Kahuku Ranch in south Hawai`i Island was purchased by the Nature Conservancy and Hawai`i Volcanoes National Park. Many viewed the purchase as a big win for conservation, because the large property contained many diverse ecosystems, and the focus could shift from ranching to preservation and restoration of the native environments.
The purchase also included nearly the entire active southwest rift zone of Mauna Loa, the largest volcano on Earth. Since the establishment of ranching on Hawai`i Island in the early 1800s, the southwest rift zone of Mauna Loa has erupted eight times (1868, 1887, 1903, 1907, 1916, 1919, 1926, and 1950).
At the lower elevations most appropriate for ranching, the land within the Kahuku ahupua`a ranges from lush pasture growing on deep ash soils, nourished by trade wind driven showers on the east, to barren lava fields to the west. In the early 1800s, the transition between the two extremes was gradual. The Mauna Loa southwest rift zone eruptions significantly sharpened the transition by progressively replacing pasture with lava at elevations optimum for ranching (below 1,500 m or 5,000 ft). At least three of the earliest eruptions also initiated a change in ranch ownership.
The first and lowest-elevation eruption began in 1868 with the onset of earthquakes in late March. On April 2, an estimated magnitude-7.9 earthquake produced extensive damage throughout the district and generated a mudflow and a local tsunami that killed 81 people. The earthquakes continued and, five days later, an eruption from Mauna Loa's lower southwest rift zone produced a fast-moving pahoehoe flow. Observers in a passing ship noted that the lava flow advanced from the vent to the ocean, a distance of 16 km (10 mi), in three-and-a-half hours.
The 1868 flow destroyed the house of Captain Robert Brown, who was managing the ranch for his brother, Theophilus. The flow advanced so quickly on the house that Captain Brown and his family escaped with only the clothes on their backs.
Soon after the eruption, Theophilus sold the ranch to a hui (group) that included George Jones, who bought out his partners' interests to became sole owner in 1877.
Another Mauna Loa eruption in 1887 produced an `a`a flow to the west of the 1868 eruption. From vent to ocean, the flow advanced 24 km (15 mi) in about 29 hours and came close - but did not damage - Jones' residential compound.
The real impact of the 1887 eruption on Jones' ranch was the flow of sightseers. George was known as a very hospitable man and, for several weeks, was forced to suspend operations in order to accommodate the hordes of curious visitors.
About a year-and-a-half after the 1887 eruption, Jones sold the ranch to Colonel Samuel Norris. Norris, described as eccentric and peculiar, was not hospitable to his fellow Caucasians. Another Mauna Loa eruption in 1907 produced lava flows to the west of the 1887 and 1868 flows, further reducing pasture lands. Tourists flocking to the new flows were not welcomed by the new ranch owner.
Norris was 66 when he bought the ranch. In 1910, when he realized he was dying, Norris essentially gave away the ranch, "selling" it to his long-time friend, Charles Macomber, for a dollar, complaining that lava flows had devalued the property. Norris died a few months later. In 1912, Macomber sold the ranch to W.O. Carter (making a profit of $89,999) for inclusion in the famed Parker Ranch.
The upper reaches of the ranch were overrun by lava in 1903, 1916, and 1926 but these eruptions did not precipitate a sale as the earlier ones had. After 1947, Kahuku Ranch changed hands two more times before the 2003 acquisition and addition to Hawai`i Volcanoes National Park.
The early decades of ranching in southern Hawai`i Island must have been difficult and, in Kahuku, success was made even harder by the encroaching volcanic activity. But ranchers and cowboys are not easily deterred, and the Hawai`i cattle industry quickly became the paniolo culture that we appreciate today.
Ranching continues on Hawai`i Island, but nowhere else has it coexisted with so many lava flows. For more on the history of Kahuku Ranch and its paniolos, check out a new book, History of Kahuku Ranch by Marge and Dennis Elwell.
Kīlauea Activity Update
Lava continues to enter the lava tube system and is carried downslope to the Puhi-o-Kalaikini lava delta, near Kalapana, where it enters the ocean and creates a large steam plume. Small and brief lava breakouts from the tube have recently been active near the end of Highway 130, just west of Kalapana. This past week, a small flow was active just west of the County Lava Viewing area, and another small flow appeared on the lower pali on Thursday, October 28.
At Kīlauea's summit, the circulating lava lake deep in the collapse pit within the floor of Halema`uma`u Crater has been visible via Webcam throughout the past week. The circulation pattern was interrupted sporadically by abrupt increases in the height of the lava surface. These periods of high lava level have been short-lived, lasting up to several hours, and each ended with a sudden drop of the lava surface back to its previous level. Volcanic gas emissions remain elevated, resulting in high concentrations of sulfur dioxide downwind.
One earthquake beneath Hawai`i Island was reported felt during the past week. A magnitude-3.0 earthquake occurred at 4:58 p.m. H.S.T on Monday, October 25, 2010, and was located offshore 47 km (29 miles) west of Honaunau at a depth of 30 km (18 miles).
Visit our Web site (http://hvo.wr.usgs.gov) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea activity summary; email questions to askHVO@usgs.gov.
Updated: November 6, 2010 (pnf)