add site
services
publishers
database
health videos
toolbar
stats
live show
health store
more stuff
JOIN/LOGIN
| advertise add site services publishers database health videos
| | about toolbar stats live show health store more stuff JOIN/LOGIN |
Hualālai (pronounced [huəˈlaːlei] in Hawaiian) is a dormant shield volcano on the island of Hawaiʻi in the Hawaiian Islands. Its peak is 8,271 ft (2,521 m) above sea level. Hualālai is one of five volcanoes on Hawaii island and it lies roughly due west of the saddle between the much higher volcanoes Mauna Kea and Mauna Loa. Hualālai forms the backdrop to the town of Kailua-Kona, which is built on the southwestern slope of this mountain, where most Kona coffee is grown.
[edit] Structure The Island of Hawaiʻi is built from five separate shield volcanoes that erupted somewhat sequentially, one overlapping the other. These are (from oldest to youngest):
Hualālai is built from a well-defined rift zone that trends approximately N50°W across its summit and a less well-defined rift zone that trends northward from a point 3 mi east of the summit.[2] The oldest dated rocks on the mountain surface are about 128,000 years before present (0.1 Mya). It is estimated that the volcano appeared above sea level some 300,000 years ago (0.3 Mya; USGS).[1] Over 100 cinder and spatter cones are arranged along the rift zones. There is no summit caldera, just a collapse crater (~ 0.3 mile across) at the top of a small lava shield.[1] Much of the southern slope (above the town of Kailua-Kona) consists of lava flows covered by a layer of volcanic ash from 10 cm (a few inches) to a meter (3 ft) thick. Hualālai appears to have entered the late stage of the eruptive cycle of Hawaiian volcanoes Hualalai is a shield volcano located on Hawaii. The summit of Hualalai is 2,521 m. (8,271 ft.) above sea level.[1] This volcano is farthest west of the five volcanoes on Hawaiian. The last eruption of Hualalai was in 1800-1801 along the northwest rift zone. When it erupted six vents opened up. It is on a hot spot in the middle of the Pacific plate. Hualalai grew above sea level approximately 300,000 years ago[2] and is in the post-shield stage of its development.[1] [edit] Recent eruptionsSix vents erupted lava between the late 1700s and 1801, two of which generated lava flows that poured into the sea along the west coast of the island. The Keāhole-Kona Airport, located only 11 km (7 mi) north of Kailua-Kona, is built atop the smaller Huehue flow (1801) just north of Keāhole Point.[3] Although Hualālai is not nearly as active as nearby Mauna Loa or Kīlauea, geologic mapping of the volcano shows that 80 percent of Hualālai's surface is covered by lava flows no older than about 5,000 years. In the past few decades, when most of the resorts, homes, and commercial buildings were built on the flanks of Hualālai, earthquake activity beneath the volcano has been low. In 1929, however, an intense swarm of earthquakes lasting more than a month was most likely caused by magma rising to near the surface. For these reasons, Hualālai is considered a potentially dangerous volcano that is likely to erupt again sometime in the next 100 years.[1] [edit] Lava stratigraphy   The USGS has divided the exposed lava flows and tephra erupted by Hualalai volcano during the last 112,000 years into 419 rock units of eight chronostratigraphic age groups. These are summarised in the table below:
[edit] References
[edit] External links
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ↑ top of page ↑ | about thumbshots |
