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Mauna Loa

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Mauna Loa
Mauna Loa Volcano.jpg
Mauna Loa as seen from the air; Hualālai is visible in the background
Highest point
Elevation 13,679 ft (4,169 m) [1]
Prominence 7,079 ft (2,158 m) [1]
Coordinates 19°28′46.3″N 155°36′09.6″W﻿ / ﻿19.479528°N 155.602667°W﻿ / 19.479528; -155.602667Coordinates: 19°28′46.3″N 155°36′09.6″W﻿ / ﻿19.479528°N 155.602667°W﻿ / 19.479528; -155.602667
Mauna Loa is located in Hawaii
Mauna Loa
Mauna Loa
Hawaii, U.S.
Parent range Hawaiian Islands
Topo map USGS Mauna Loa
Age of rock 700,000–1 million[2]
Mountain type Shield volcano
Volcanic arc/belt Hawaiian-Emperor seamount chain
Last eruption March to April 1984[2]
First ascent Ancient times
Easiest route Ainapo Trail






Position of Mauna Loa on Hawaiʻi island
Landsat mosaic; recent lava flows appear in black

Like all Hawaiian volcanoes, Mauna Loa was created as the Pacific tectonic plate moved over the Hawaiian hotspot in the Earth's underlying mantle.[6] The Hawaii island volcanoes are the most recent evidence of this process that, over 70 million years, has created the 3,700 mi (6,000 km)-long Hawaiian–Emperor seamount chain.[7] The prevailing view states that the hotspot has been largely stationary within the planet's mantle for much, if not all of the Cenozoic Era.[7][8] However, while the Hawaiian mantle plume is well-understood and extensively studied, the nature of hotspots themselves remain fairly enigmatic.[9]

Mauna Loa is one of five subaerial volcanoes that make up the island of Hawaiʻi, created by the Hawaii hotspot.[10] The oldest volcano on the island, Kohala, is more than a million years old,[11] and Kīlauea, the youngest, is believed to be between 300,000 and 600,000 years of age.[10] Lōʻihi Seamount on the island's flank is even younger, but has yet to breach the surface.[12] At 1 million to 700,000 years of age,[2] Mauna Loa is the second youngest of the five volcanoes on the island, making it the third youngest volcano in the Hawaiian – Emperor seamount chain, a chain of shield volcanoes and seamounts extending from Hawaii to the Kuril–Kamchatka Trench in Russia.[13]

Following the pattern of Hawaiian volcano formation, Mauna Loa would have started as a submarine volcano, gradually building itself up through underwater eruptions of alkali basalt before emerging from the sea through a series of surtseyan eruptions[14] about 400,000 years ago. Since then, the volcano has remained active, with a history of effusive and explosive eruptions, including 33 eruptions since the first well-documented eruption in 1843.[2] Although Mauna Loa's activity has been overshadowed in recent years by that of its neighbor Kīlauea,[10] it remains active.[2]


Mokuʻāweoweo, Mauna Loa's summit caldera, covered in snow.

Mauna Loa is the largest subaerial and second largest overall volcano in the world (behind Tamu Massif),[15] covering a land area of 5,271 km2 (2,035 sq mi) and spans a maximum width of 120 km (75 mi).[2] Consisting of approximately 65,000 to 80,000 km3 (15,600 to 19,200 cu mi) of solid rock,[16] it makes up more than half of the surface area of the island of Hawaiʻi. Combining the volcano's extensive submarine flanks (5,000 m (16,400 ft) to the sea floor) and 4,170 m (13,680 ft) subaerial height, Mauna Loa rises 9,170 m (30,085 ft) from base to summit,[2][17] greater than the 8,848 m or 29,029 ft[18] elevation of Mount Everest from sea level to its summit. In addition, much of the mountain is invisible even underwater: its mass depresses the crust beneath it by another 8 km (5 mi), in the shape of an inverse mountain,[19] meaning the total height of Mauna Loa from the start of its eruptive history is about 17,170 m (56,000 ft).[20]

Mauna Loa is a typical shield volcano in form, taking the shape of a long, broad dome extending down to the ocean floor whose slopes are about 12° at their steepest, a consequence of its extremely fluid lava. The shield-stage lavas that built the enormous main mass of the mountain are tholeiitic basalts, like those of Mauna Kea, created through the mixing of primary magma and subducted oceanic crust.[21] Mauna Loa's summit hosts three overlapping pit craters arranged northeast-southwest, the first and last roughly 1 km (0.6 mi) in diameter and the second an oblong 4.2 km × 2.5 km (2.6 mi × 1.6 mi) feature; together these three craters make up the 6.2 by 2.5 km (3.9 by 1.6 mi) summit caldera Mokuʻāweoweo,[22] so named for the Hawaiian ʻāweoweo fish (Priacanthus meeki), purportedly due to the resemblance of its eruptive fires to the coloration of the fish.[23] Mokuʻāweoweo's caldera floor lies between 170 and 50 m (558 and 164 ft) beneath its rim and it is only the latest of several calderas that have formed and reformed over the volcano's life. It was created between 1,000 and 1,500 years ago by a large eruption from Mauna Loa's northeast rift zone, which emptied out a shallow magma chamber beneath the summit and collapsed it into its present form.[22] Additionally, two smaller pit craters lie southwest of the caldera, named Lua Hou (New Pit) and Lua Hohonu (Deep Pit).[16]



Mauna Loa has complex interactions with its neighbors, Hualālai to the west, Mauna Kea to the north, and particularly Kīlauea to the east. Lavas from Mauna Kea intersect with Mauna Loa's basal flows as a consequence of Kea's older age,[27] and Mauna Kea's original rift zones were buried beneath post-shield volcanic rocks of Mauna Loa;[28] additionally, Mauna Kea shares Mauna Loa's gravity well, depressing the ocean crust beneath it by 6 km (4 mi).[27] There are also a series of normal faults on Mauna Loa's northern and western slopes, between its two major rift zones, that are believed to be the result of combined circumferential tension from the two rift zones and from added pressure due to the westward growth of neighboring Kīlauea.[29]



A view of Mauna Loa taken from a Pu'u near The Onizuka Center for International Astronomy Visitor Information Station at the 9300 ft. level of Mauna Kea.

Mauna Loa is tall enough to have experienced glaciation during the last ice age, 25,000 to 15,000 years ago.[6] Unlike Mauna Kea, on which extensive evidence of glaciation remains even today,[32] Mauna Loa was at the time and has remained active, having grown an additional 150 to 300 m (492 to 984 ft) in height since then and covering any glacial deposits beneath new flows; strata of that age doesn't occur until at least 2,000 m (6,562 ft) down from the volcano's summit, too low for glacial growth. Mauna Loa also lacks its neighbor's summit permafrost region, although sporadic ice persists in places. It is speculated that extensive phreatomagmatic activity occurred during this time, contributing extensively to ash deposits on the summit.[6]

Eruptive history

Prehistoric eruptions

A cinder cone and surrounding flows on Mauna Loa

To have reached its enormous size within its relatively short (geologically speaking) 600,000 to 1,000,000 years of life, Mauna Loa would logically have had to have grown extremely rapidly through its developmental history,[33] and extensive charcoal-based radiocarbon dating (perhaps the most extensive such prehistorical eruptive dating on Earth[34][35]) has amassed a record of almost two hundred reliably dated extant flows confirming this hypothesis.[33]


Studies have shown that a cycle occurs in which volcanic activity at the summit is dominant for several hundred years, after which activity shifts to the rift zones for several more centuries, and then back to the summit again. Two cycles have been clearly identified, each lasting 1,500–2,000 years. This cyclical behavior is unique to Mauna Loa among the Hawaiian volcanoes.[36] Between about 7,000 and 6,000 years ago Mauna Loa was largely inactive. The cause of this cessation in activity is not known, and no known similar hiatus has been found at other Hawaiian volcanoes except for those currently in the post-shield stage. Between 11,000 and 8,000 years ago, activity was more intense than it is today.[34] However, Mauna Loa's overall rate of growth has probably begun to slow over the last 100,000 years,[37] and the volcano may in fact be nearing the end of its tholeiitic basalt shield-building phase.[38]

Recent history

Ancient Hawaiians have been present on Hawaiʻi island for about 1,500 years, but they preserved almost no records on volcanic activity on the island beyond a few fragmentary accounts dating to the late 18th and early 19th centuries.[39] Possible eruptions occurred around 1730 and 1750 and sometime during 1780 and 1803.[40][41] A June 1832 eruption was witnessed by a missionary on Maui, but the 190 km (118 mi) between the two islands and lack of apparent geological evidence have cast this testimony in doubt. Thus the first entirely confirmed historically witnessed eruption was a January 1843 event, since which Mauna Loa has erupted anew 32 times.[39]

Historical eruptions at Mauna Loa are typically Hawaiian in character and rarely violent, starting with the emergence of lava fountains over a several kilometer long rift colloquially known as the "curtain of fire" (often, but not always, propagating from Mauna Loa's summit[25]) and eventually concentrating at a single vent, its long-term eruptive center.[16][24] Activity centered on its summit are usually followed by flank eruptions up to a few months distant,[42] and although Mauna Loa is historically less active than that of its neighbor Kilauea, it tends to produce greater volumes of lava over shorter periods of time.[43] Most eruptions are centered at either the summit or either of its two major rift zones; within the last two hundred years, 38 percent of eruptions occurred at the summit, 31 percent at the northeast rift zone, 25 percent at the southwest rift zone, and the remaining 6 percent from northwest vents.[34] 40 percent of the volcano's surface consists of lavas less than a thousand years old,[43] and 98 percent of lavas less than 10,000 years old.[33] In addition to the summit and rift zones, Mauna Loa's northwestern flank has also been the source of three historical eruptions.[43]

The 1843 event was followed by eruptions in 1849, 1851, 1852, and 1855,[39] with the 1855 flows being particularly extensive.[34] 1859 marked the largest of the three historical flows that have been centered on Mauna Loa's northwestern flank, producing a long lava flow that reached the ocean on Hawaii island's west coast, north of Kiholo Bay.[43] An eruption in 1868 occurred alongside the enormous 1868 Hawaii earthquake,[34] a magnitude eight event that claimed 77 lives and remains the largest earthquake ever to hit the island.[44] Following further activity in 1871, Mauna Loa experienced nearly continuous activity from August 1872 through 1877, a long-lasting and voluminous eruption lasting approximately 1,200 days and never moving beyond its summit.[39][45][46] A short single-day eruption in 1877 was unusual in that it took place underwater, in Kealakekua Bay and within a mile of the shoreline; curious onlookers approaching the area in boats reported unusually turbulent water and occasional floating blocks of hardened lava.[43] Further eruptions occurred in 1879 and then twice in 1880,[39] the latter of which extended into 1881 and came within the present boundaries of the island's largest city, Hilo; however at the time the settlement was a shore-side village located further down the volcano's slope, and so was unaffected.[34][43]

Hualalai Kohala Kilauea Mauna Kea

Mauna Loa continued its activity, and of the eruptions that occurred in 1887, 1892, 1896, 1899, 1903 (twice), 1907, 1914, 1916, 1919, and 1926,[39] three (in 1887, 1919, and 1926) were partially subaerial.[34] The 1926 eruption in particular is noteworthy for having inundated of a village near Hoopuloa, destroying 12 houses, a church, and a small harbor.[47] After an event in 1933, Mauna Loa's 1935 eruption caused a public crisis when its flows started to head towards Hilo.[39] A bombing operation was decided upon to try and divert the flows, planned out by then-lieutenant colonel George S. Patton. The bombing, conducted on December 27, was declared a success by Thomas A. Jaggar, director of the Hawaiian Volcano Observatory, and lava stopped flowing by January 2, 1936. However, the role the bombing played in ending the eruption has since been heavily disputed by volcanologists.[48] A longer but summit-bound event in 1940 was comparatively less interesting.[39]

Mauna Loa's 1942 eruption occurred only four months after the attack on Pearl Harbor and United States entry into World War II, and created a unique problem for the wartime United States. Occurring during an enforced nighttime blackout on the island, the eruption's luminosity forced the government to issue a gag order on the local press, hoping to prevent news of its occurrence spreading for fear that the Japanese would use it to launch a bombing run on the island. However, as flows from the eruption rapidly spread down the volcano's flank and threatened the ʻOlaʻa flume, Mountain View's primary water source, the United States Air Force decided to drop its own bombs on the island in the hopes of redirecting the flows away from the flume; sixteen bombs weighing between 300 and 600 lb (136 and 272 kg) each were dropped on the island, but produced little effect. Eventually the eruption ceased on its own.[41][49]

Following a 1949 event the next major eruption at Mauna Loa occurred in 1950. Originating from the volcano's southwestern rift zone, the eruption remains the largest rift event in the volcano's modern history, lasting 23 days, emitting 376 million cubic meters of lava, and reaching 24 km (15 mi) out to the ocean within 3 hours. The 1950 eruption was not the most voluminous eruption on the volcano (the long-lived 1872-1877 event produced more than twice as much material) but it was easily one of the fastest-acting, producing the same amount of lava as the 1859 eruption in a tenth of the time.[46] Flows overtook the village of Hoʻokena-mauka in South Kona, crossed Hawaii Route 11, and reached the sea within four hours of eruption, and although there was no loss of life the village was permanently destroyed.[50] After the 1950 event Mauna Loa entered an extended period of dormancy, interrupted only by a small single-day summit event in 1975. However it rumbled to life again in 1984, manifesting first at Mauna Loa's summit and then producing a narrow, channelized 'a'a flow that advanced downslope to within 6 km (4 mi) of Hilo, close enough to illuminate the city at nighttime. However the flow got no closer, as two natural levees further up its pathway consequently broke and diverted active flows.[51][52]

Mauna Loa has not erupted since, and as of January 2013 has remained quiet for nearly 29 years, its longest period of quiet in recorded history.[39][53]



Although volcanic eruptions in Hawaiʻi rarely produce casualties (the only direct historical fatality due to volcanic activity on the island occurred at Kīlauea in 1924, when an unusually explosive eruption hurled rocks at an onlooker), property damage due to inundation by lava is a common and costly hazard.[56] Hawaiian-type eruptions usually produce extremely slow-moving flows that advance at walking pace, presenting little danger to human life, but this is not strictly the case;[57] Mauna Loa's 1950 eruption emitted as much lava in three weeks as Kīlauea's current eruption produces in three years and reached sea level within four hours of its start, overrunning the village of Hoʻokena Mauka and a major highway on the way there.[46] An earlier eruption in 1926 overran the village of Hoʻōpūloa Makai,[47] and Hilo, partly built on lavas from the 1880-81 eruption, is at risk from future eruptions.[43] The 1984 eruption nearly reached the city, but stopped short after the flow was redirected upstream.[58]

A potentially greater hazard at Mauna Loa is a sudden, massive collapse of the volcano's flanks, like the one that struck the volcano's west flank between 100,000 and 200,000 years ago and formed the present-day Kealakekua Bay.[31] Deep fault lines are a common feature on Hawaiian volcanoes, allowing large portions of their flanks to gradually slide downwards and forming structures like the Hilina Slump and the ancient Ninole Hills; large earthquakes could trigger rapid flank collapses along these lines, creating massive landslides and possibly triggering equally large tsunamis. Undersea surveys have revealed numerous landslides along the Hawaiian chain and evidence of two such giant tsunami events: 200,000 years ago, Molokaʻi experienced a 75 m (246 ft) tsunami, and 100,000 years ago a megatsunami 325 m (1,066 ft) high struck Lānaʻi.[59] A more recent example of the risks associated with slumps occurred in 1975, when the Hilina Slump suddenly lurched forward several meters, triggering a 7.2 Mw earthquake and a 14 m (46 ft) tsunami that killed two campers at Halape.[60]



Established on Kīlauea in 1912, the Hawaiian Volcano Observatory (HVO), presently a branch of the United States Geological Survey, is the primary organization associated with the monitoring, observance, and study of Hawaiian volcanoes.[61] Thomas A. Jaggar, the observatory's founder, attempted a summit expedition to the volcano to observe its 1914 eruption, but was rebuffed by the arduous trek required (see Ascents). After soliciting help from Lorrin A. Thurston, in 1915 he was able to persuade the US Army to construct a "simple route to the summit" for public and scientific use, a project completed in December of that year; the Observatory has maintained a presence on the volcano ever since.[42]



Human history


The first Ancient Hawaiians to arrive on Hawaii island lived along the shores where food and water were plentiful.[65] Flightless birds that had previously known no predators became a staple food source.[66] Early settlements had a major impact on the local ecosystem, and caused many extinctions, particularly amongst bird species, as well as introducing foreign plants and animals and increasing erosion rates.[67] The prevailing lowland forest ecosystem was transformed from forest to grassland; some of this change was caused by the use of fire, but the main reason appears to have been the introduction of the Polynesian Rat (Rattus exulans).[68]

Ancient Hawaiian religious practice holds that the five volcanic peaks of the island are sacred, and regards Mauna Loa, the largest of them all, with great admiration;[69] but what mythology survives today consists mainly of oral accounts from the 18th century first compiled in the 19th. Most of these stories agree that the Hawaiian volcano deity, Pele, resides in Halemaʻumaʻu Crater on Kilauea; however a few place her home at Mauna Loa's summit caldera Mokuʻāweoweo, and the mythos in general associates her with all volcanic activity on the island.[70] Regardless, Kīlauea's lack of a geographic outline and strong volcanic link to Mauna Loa led to it being considered an offshoot of Mauna Loa by the Ancient Hawaiians, meaning much of the mythos now associated with Kīlauea was originally directed at Mauna Loa proper as well.[71]:154–155


European summiting attempts




Menzies made a third attempt to summit Mauna Loa in February 1794. This time the botanist consulted King Kamehameha I for advice and learned that he could take canoes to the south and follow the ʻAinapō Trail, not knowing of its existence beforehand. Significantly better prepared, Menzies, Lieutenant Joseph Baker and Midshipman George McKenzie of the Discovery, and a servant (most likely Jonathan Ewins, listed on the ship's muster as "Botanist's L't") reached the summit, which Menzies estimated to be 4,156 m (13,635 ft) high with the aid of a barometer (consistent with a modern value of 4,169 m (13,678 ft)). He was surprised to find heavy snow and morning temperatures of −3 °C (27 °F), and was unable to compare the heights of Mauna Loa and Kea but correctly supposed the latter to be taller based on its larger snow cap.[74] The feat of summitting Mauna Loa was not to be repeated for forty years.[74]


The next successful ascent was made on January 29, 1834, 40 years later, by the Scottish botanist David Douglas, who also reached the summit caldera using the ʻAinapō Trail. By the time Douglas reached the summit the environment had put him under extreme duress, but he nonetheless stayed overnight to make measurements of the summit caldera's proportions and record barometric data on its height, both now known to be widely inaccurate. Douglas collected biological samples on the way both up and down, and after a difficult and distressing descent began collating his samples; he planned to return to England, but instead several months later his body was mysteriously discovered crushed in a pit besides a dead wild boar.[75]

Isidor Löwenstern successfully climbed Mauna Loa in February 1839, only the third successful climb in 60 years.[74]

Wilkes expedition

Wilkes Campsite
Wilkes campsite.jpg
Sketch by ship's artist Alfred Thomas Agate
Nearest city Hilo, Hawaii
Area 4 acres (16,000 m2)
Built 1840
Architect Charles Wilkes
Architectural style Stone shelter
NRHP Reference # 74000295[76]
Added to NRHP July 24, 1974






Sketch of Mokuʻāweoweo from Wilkes' journal


On Monday, January 11, Wilkes hiked around the summit crater. Using an optical method, he estimated Mauna Kea was only 193 feet (59 m) higher (modern measurements are 104 feet (32 m)). On January 13, 1841, he had "Pendulum Peak, January 1841 U.S. Ex, Ex." cut into a rock at the site. The tents were dismantled and Hawaiians carried the gear down over the next three days, while Wilkes enjoyed a lomilomi Hawaiian massage. He continued his measurements at lower elevations and left the island on March 5. For all the effort he did not obtain any significant results, attributing gravity discrepancies to "the tides".[75]

The Wilkes expedition's camp site's ruins are the only known physical evidence in the Pacific of the U. S. Exploring Expedition.[78] The camp site was listed on the National Register of Historic Places on July 24, 1974 as site 74000295,[76] and is state historic site 10-52-5507.[79]





Mauna Loa has a tropical climate with warm temperatures at lower elevations and cool to cold temperatures higher up year-round. Below is the table for the slope observatory, which is at 10,000 feet (3,000 m) in the alpine zone. The highest recorded temperature was 85 °F (29 °C) and the lowest was 18 °F (−8 °C) on February 18, 2003 and February 20, 1962, respectively.[82]

Climate data for Mauna Loa slope observatory (1961–1990)
Record high °F (°C) 67
Average high °F (°C) 49.8
Average low °F (°C) 33.3
Record low °F (°C) 19
Average precipitation inches (mm) 2.3
Average snowfall inches (cm) 0.0
Source: NOAA[83]


Atmospheric CO2 concentrations measured at the Mauna Loa Observatory.



See also


  1. ^ a b "Mauna Loa, Hawaii". Retrieved 12 December 2012. 
  9. ^ Clague, David A.; Dalrymple, G. Brent (1987). "The Hawaiian-Emperor Volcanic Chain – Geological Evolution". Volcanism in Hawaii: papers to commemorate the 75th anniversary of the founding of the Hawaii Volcano Observatory (PDF). Professional Paper 1350. 1. United States Geological Survey. p. 32. 
  11. ^ "Kohala—Hawaii's Oldest Volcano". Hawaiian Volcano ObservatoryUnited States Geological Survey. 20 March 1998. Retrieved 29 January 2012. 
  13. ^ W. J. Kious & R. I. Tilling (1996). "Hotspots": Mantle thermal plumes (1.14 ed.). United States Geological Survey. ISBN 0-16-048220-8. Retrieved 9 December 2012. 
  16. ^ a b c d G. MacDonald & D. Hubbard (1974). "Mauna Loa, Fiery Colossus of the Pacific". National Park Service (published online 24 March 2006). Retrieved 9 December 2012.  Check date values in: |publication-date= (help)
  19. ^ J.G. Moore (1987). Subsidence of the Hawaiian Ridge. Volcanism in Hawaii: Geological Survey Professional Paper, Volume 1350, Issue 1. 
  21. ^ Claude Herzberg (30 November 2006). "Petrology and thermal structure of the Hawaiian plume from Mauna Kea volcano". Nature. Nature Publishing Group. 444 (7119): 605–9. Bibcode:2006Natur.444..605H. doi:10.1038/nature05254. PMID 17136091. Retrieved 10 December 2012. 
  23. ^ "Place Names of Hawaii – Moku-ʻāweoweo". Ulukau - Hawaiian Electronic Library. Retrieved 11 December 2012. 
  25. ^ a b c F. Amelung, S. H. Yun, T. R. Walter, P. Segall, S. W. Kim; Yun; Walter; Segall; Kim (18 May 2007). "Stress Control of Deep Rift Intrusion at Mauna Loa Volcano, Hawaii". Science. American Association for the Advancement of Science. 316 (5827): 1026–1030. Bibcode:2007Sci...316.1026A. doi:10.1126/science.1140035. Retrieved 16 December 2012. 
  26. ^ "What's up with Mauna Loa?". Hawaiian Volcano Observatory - United States Geological Survey. 23 October 2001. Retrieved 16 December 2012. 
  29. ^ "Rift Zones". Oregon State University. Retrieved 13 December 2012. 
  41. ^ a b John Seach. "Mauno Loa Volcano - John Seach". Retrieved 24 January 2013. 
  43. ^ a b c d e f g h John Watson (18 July 1997). "Lava Flow Hazard Zone Maps: Mauna Loa". United States Geological Survey. Retrieved 12 December 2012. 
  49. ^ "Shhh! Don't tell there is an eruption - Eruption of 1942". Hawaiian Volcano ObservatoryUnited States Geological Survey. 27 April 1998. Retrieved 24 January 2013. 
  52. ^ "1984 Eruption: March 25 - April 15". Hawaiian Volcano ObservatoryUnited States Geological Survey. 17 September 2004. Retrieved 24 January 2013. 
  55. ^ Nick Varley. "Decade Volcano Program IDNDR - IAVCEI - 1990/2000". Société Volcanologique Européenne. Retrieved 25 January 2013. 
  59. ^ Robert and Barbara Decker (1997). Volcanoes (3rd ed.). New York: W.H. Freeman & Co, Ltd. ISBN 0-7167-3174-6. 
  66. ^ "Culture: The First Arrivals: Native Hawaiian Uses" (PDF). Mauna Kea Mountain Reserve Master Plan. University of Hawaii. Retrieved 2 September 2012. 
  71. ^ Various authors (1987). R. W. Decker; et al., eds. Volcanism in Hawaii: papers to commemorate the 75th anniversary of the founding of the Hawaii Volcano Observatory (PDF). United States Geological Survey Professional Paper, 1350. 1. United States Geological Survey. Retrieved 2 September 2012. 
  72. ^ a b Russell A. Apple (20 August 1974). "National Register Of Historic Places Inventory - Nomination Form for Federal Properties - Ainapo Trail" (PDF). National Park Service. Retrieved 27 January 2013. 
  73. ^ Rick Warshauer (October 2005). "The Proposed Mauka Trails System: The Roles and History of Trails on the Big Island" (PDF). The Nature Conservancy. Retrieved 27 January 2013. 
  75. ^ a b c d e Roberta A. Sprague (1991). "Measuring the Mountain: the United States Exploring Expedition on Mauna Loa, 1840-1841" (PDF). Hawaiian Journal of History. Hawaiian Historical Society. 25. hdl:10524/359. 
  77. ^ Charles Wilkes (1849). Narrative of the United States Exploring Expedition. Volume IV. G. P. Putnam. p. Pages 111–162. 
  79. ^ Historic Places in Hawaii County on official state web site
  82. ^ "Period of Record General Climate Summary - Temperature". MAUNA LOA SLOPE OBS, HAWAII. NOAA. Retrieved 2012-06-05. 

External links