Hawaiian Volcanoes:Hawaiian Volcanoes:Fire Walking With the Lava JunkiesFire Walking With the Lava Junkies

From Fun on the Net with additions From Fun on the Net with additions by Joe Naumann, UMSLby Joe Naumann, UMSL

The “Big Island”The “Big Island”

• The only active volcanoes in Hawaii today are found on the Big Island of Hawaii. These are dome, or shield, volcanoes that have formed over a hotspot on the Pacific plate. The older, smaller islands had active volcanoes when they were located over the hotspot. They are smaller now than they were before because today erosion from waves has reduced them in size.

HAWAIIHAWAII

• The Hawaiian Islands are at the southeastern end of a chain of volcanoes that began to form more than 70 million years ago. Many of these volcanoes formed islands that have subsided and eroded beneath sea level, and some of the old volcanoes probably never reached sea level. Each Hawaiian island is made of one or more volcanoes, which first erupted on the sea floor and only emerged above the ocean's surface after countless eruptions.

• The largest and most southeastern island of the chain, Hawai`i, consists of five volcanoes. Kilauea, Mauna Loa, and Hualalai have erupted in the past 200 years. Lo`ihi, the youngest volcano of the Hawaiian Volcanic Chain, is still about 1,000 meters beneath the ocean's surface. East Maui Volcano, commonly known as Haleakala, on the island of Maui, is the only other Hawaiian volcano to have erupted since the late 1700's.

• Map of the southeastern or "windward" Hawaiian Islands. The islands owe their existence to a "hot spot" in the Earth's mantle that has changed location only slightly over the past 70 million years. This hot spot is located beneath the southeastern part of Hawai`i.

Youngest island

Oldest island

• Map of the Hawaiian Islands on the previous slide, shows a chain of volcanoes that stretches about 2,700 km in a northwesterly direction from the Island of Hawai`i. The age of the volcanoes that form the islands increases progressively from Hawai`i, where the volcanoes are still active, to the northwest end, where the volcanoes are about 30 million years old. The chain of volcanoes continues as seamounts for another 3,000 km; the chain bends sharply to the northward about 700 km beyond this map and becomes the Emperor Seamounts.

Map of Kilauea Eruptions 1983 - Map of Kilauea Eruptions 1983 - presentpresent

The AdventureThe Adventure

• "We took a helicopter to the rim and hiked about a mile [1.6 kilometers] into the steaming cauldron of Kilauea's Pu'u 'O'o crater to this skylight. Geologists call the skylight the Cookie Monster because it really looks like the shape of the character on Sesame Street.“From the helicopter, we saw lava splashing and frothing 50 feet [15 meters] below the surface in these 75- to 100-foot-wide [23- to 30-meter-wide] pools.

Plumes of gas escaping from vents as Plumes of gas escaping from vents as lava meets airlava meets air

Lava breaks out of its shell of Lava breaks out of its shell of hardened, black rockhardened, black rock

• This is a breakout, or a live surface flow of molten rock. The magma was oozing under the skin of cooled black rock—it's hotter than hell up there. Eventually a buildup of pressure under a certain place will crack the surface over it, and the lava will break out.

The Highcastle lava bench (new land The Highcastle lava bench (new land that is formed as lava cools)that is formed as lava cools)

• This was our final quest—the ocean entry at Highcastle, the holy grail for lava photographers. The lava was coming over the last cliff before entering the ocean.

A lava breakout from newly cooled A lava breakout from newly cooled rockrock

• This is wild. As the drops break out down the slope, the pressure moving the lava, pushing on the cooling skin above it, twists the skin into ropes. This is classic pahoehoe lava. Even where I was standing, the temperature underfoot was a few hundred degrees [approximately 150°C] at least, and there are radiant rocks above me.

Lava spiraling down a slopeLava spiraling down a slope

• This shot may look like a dreamy day on the side of a volcano, but it was really wicked. I am standing downwind of an a'a flow, which is notorious for emitting an exceptional amount of radiant heat. It was really, truly ferociously hot.

The deceptive calm of an extremely The deceptive calm of an extremely hot flowhot flow