1973 photograph of Halema‘uma‘u Crater, site of an explosive eruption in 1924, within the main caldera
|Elevation: ||4,091 ft (1,247 m) |
|Latitude: ||19° 25′ 15.95″ N |
|Longitude: ||155° 17′ 12.34″ W |
|Location: ||Hawai‘i |
|Range: ||Hawaiian Islands |
|Type: ||Shield volcano |
Kīlauea is an active volcano in the Hawaiian Islands, one of seven shield volcanos that together form the Island of Hawai‘i. In Hawaiian, the word kīlauea means "spewing" or "much spreading", in reference to the mountain's frequent outpouring of lava. It is presently the most active volcano, and certainly the most visited active volcano, on the planet. Kīlauea is just the most recent of a long series of volcanoes that created the Hawaiian Archipelago, as the Pacific Plate moved over a more or less fixed hotspot in the earth's mantle (see, however, Lo‘ihi).
Kīlauea's geographical location is 19.452 North, 155.292 West. It lies against the southeast flank of much larger Mauna Loa, whose massive size and elevation (to 13,677 feet or 4,169 m) is the result of three huge shield volcanoes -- extinct Ninole and Kulani are almost completely buried beneath the still active Mauna Loa. Kīlauea rises only 4,091 feet (1,247 m) above sea level, and thus from the summit caldera appears as a broad shelf of uplands well beneath the long profile of occasionally snow-capped Mauna Loa, 15 miles (24 km) distant.
First-time visitors to Kīlauea, not familiar with how different the profile of a shield volcano can be compared with stratovolcanoes like Mt. Fuji, Mount Hood, and Mount St. Helens, are usually blissfully unaware they are approaching the summit of an active volcano as they make the drive up through the cloud forest on State Rte. 11 to Hawai‘i Volcanoes National Park from Hilo—or coming from Kailua-Kona via South Point across the Ka‘ū Desert. From Hilo, the highway heads south to Kea‘au, then turns abruptly westward to begin the climb to the Kīlauea caldera. For some 20 miles (32 km) the road runs relatively straight, making a 4,000 ft (1,200 m) ascent. However, most of this climb is actually on the heavily vegetated flank of Mauna Loa; the crossing onto lava flows issued from Kīlauea is about 1 mile west of Glenwood, 18 miles (29 km) from Hilo. The Mauna Loa flows are several thousand years old; the lightly vegetated Kīlauea flows are only 350 to 500 years old.
Glowing ‘a‘a flow front advancing over pāhoehoe on the coastal plain of Kīlauea in Hawai‘i.
Driving from the Kona Coast, the immense size of the Big Island becomes apparent: from Kailua-Kona it is 98 miles (158 km) on the Māmalahoa Highway (State Rte. 11) to Kīlauea. After passing around the southern end of Mauna Loa, the highway turns northeastward towards Kīlauea once past the town of Nā‘ālehu. Yet, as from the Hilo side, the long climb from near sea level to the summit is all on the flank of Mauna Loa. Not until the Sulfur Bank scarp (the northwestern edge of Kīlauea Caldera), near the intersection of Crater Rim Drive in Hawai‘i Volcanoes National Park, does the road cross over onto Kīlauea. However, the highway parallels the line of contact between the two volcanoes—always less than 1 mile to the southeast—from the vicinity of Punalu‘u at the coast to the caldera at the summit.
The highway route from the west (State Rte. 11) is vastly different from that seen when coming from Hilo. The highway approaches Kīlauea through a desert on the leeward slope called Ka‘ū. Kīlauea's height of 4000 ft is sufficient to force most of the moisture out of the impinging Northeast Trades, leaving Ka‘ū in the rain shadow of the "low" mountain. This area is also the very active southwest rift zone of Kīlauea, a prolific ash producer. Winds redistribute the ash, causing dust storms and forming dunes across a landscape barren of most vegetation.
The caldera and Halemaumau
Hawai‘i Volcanoes National Park encompasses a portion of Kīlauea, and the park visitor center is located near the margin of the summit caldera, overlooking a large pit crater called Halema‘uma‘u. The roughly circular caldera measures 3x5 km (or 6x6 km, including the outermost ring faults).
Eruptions at Kilauea originate primarily either from the summit caldera or along either of the lengthy East and Southwest rift zones that extend from the caldera to the sea. There are almost continual eruptions with many of the lava flows reaching to the Pacific Ocean shore. About 90% of the surface of Kīlauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years.
There were forty-five eruptions of Kīlauea in the twentieth century; the latest Kīlauea eruption began in January 1983 along the East rift zone. This long-term ongoing eruption from Pu‘u ‘Ō‘ō-Kūpa‘ianahā has produced lava flows that have traveled 11-12 km from the vents to the sea, covering over about 104 km² of land on the Southern flank of Kīlauea and building 2 km² of new land. Since 1983 more than 1.9 km³ of lava has been produced, making the 1983-to-present eruption the largest historic eruption of Kīlauea.
The 1990 lava flow in particular was notable for being destructive of property. In the 1990 lava flow the towns of Kalapana and Kaimū were totally destroyed, as was Kaimū Bay, Kalapana Black Sand Beach, and a large section of State Rte. 130, which now abruptly dead-ends at the lava flow.
The eruption from Kilauea also is known for creating vog, or volcanic smog, which affects many areas of the island of Hawai'i and sometimes the entire state.
Kīlauea is said to be the present home of Pele, the volcano goddess of ancient Hawaiian legend.
- Hawaiian Volcano Observatory's Kilauea website (http://hvo.wr.usgs.gov/kilauea/)
- Hawaiian Volcano Observatory's Kilauea eruption update website (updated daily) (http://hvo.wr.usgs.gov/kilauea/update/main.html)
- US Geological Survey information about Kīlauea (http://www.volcano.si.edu/gvp/reports/usgs/archive.cfm?volcano=kilauea/)
- Hawaii Volcanoes National Park website (http://www.nps.gov/havo/)
- Lava Quest (http://members.ozemail.com.au/~rodeime/kilauea/) Personal account of hiking around Kilauea by Roderick Eime