Maui Geology

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Maui Geology Environment 1.2 million year
old Second largest island in the main chain 727.3
square miles of land area Highest elevation is
5,788 feet Largest perennial stream is 43 million
gallons (Iao Stream measures 163,000 cubic
meters per day) Haleakala crater volcano, East
Maui Shield Volcano last erupted in 1790
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The Island of Maui is made of two volcanoes West
Maui and East Maui. Most of the West Maui shield
(20.9N, 156.6W) formed between 2-1.3 million
years ago. A central caldera has been identified
roughly in the area of the present-day Iao
Valley. Alkalic basalts capped the volcano about
1.2 million years ago. Four small eruptions
occurred during the rejuvenated stage on West
Maui, probably about 1 million years ago. The
volcano is deeply dissected by numerous valleys.
West Maui has not erupted in historic time and is
considered to be extinct. East Maui Volcano,
often also (but incorrectly) called Haleakala, is
the easternmost of the two shield volcanoes that
make the Island of Maui. East Maui Volcano
(20.7N, 156.2W) is the third largest Hawaiian
shield volcano. Three rift zones can be clearly
seen in the above Space Shuttle photograph
(compare with map below).
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West Maui Volcano
Maui
Haleakala
East Maui Volcano
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Maui Nui The four islands of Maui, Molokai,
Lanai, and Kahoolawe were once all connected as
a vast landmass known as Maui Nui, literally "big
Maui." This concept was first proposed 60 years
ago by geologist Harold Stearns, who recognized
the geologic evidence for repeated episodes of
island submergence and reemergence. Recently,
Jonathan Price of the Smithsonian Institution
modeled the area's submergence history using a
computer-based geographic information system
(GIS). The model examines the effects of global
sea-level change, age of volcanism, and likely
rates of volcano subsidence. Using Price's model,
we can watch the response of Maui Nui to
subsidence and sea-level change as we move the
clock forward or back.
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Haleakala Observatory
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Haleakala
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Maui Geology Environment Second largest island
in the main chain 727.3 square miles of land
area Highest elevation is 5,788 feet Largest
perennial stream is 43 million gallons (Iao
Stream measures 163,000 cubic meters per day) The
long-term average water budget for east Maui was
estimated for natural land-use conditions. The
average rainfall, fog-drip, runoff,
evapotranspiration, and ground-water recharge
volumes for the east Maui study area are 2,246
Mgal/d, 323 Mgal/d, 771 Mgal/d, 735 Mgal/d, and
1,064 Mgal/d, respectively.