Photos from the Big Island of Hawai'i

Mauna Loa volcano is an enormous shield volcano that rises more than 13,000' above sea level.  When the height above its true base, far below sea level is included, it stands nearly twice as high as Mt. Everest! Its slopes rise at less than a 5º angle. The volcano is periodically active with its last eruption in 1984. Seen here from the edge of Kilauea caldera, the summit stands more than 8,000' higher in elevation and is more than 35 miles away.

Mauna Kea is the highest volcano in Hawai'i. It has no recorded eruptive activity. The fresh looking aa lava in the foreground is from the 1848 Mauna Loa eruption. The summit is home to a large concentration of astronomical and meteorological observatories. Abundant, young cinder cones dot the southern flank of the mountain.

Hualalai volcano, on the west side of the island, is also considered 
to be active. Its last eruption occurred in 1802.

This view looks across Kilauea caldera with Mauna Loa in the background. Kilauea is one of the most, if not the most, active volcanoes in the world. The current phase of activity began on January 3, 1983, the day I arrived with my first Hawaiian study group from Colgate University.

The floor of Kilauea caldera is covered with a glassy pahoehoe lava. These lavas were extruded during eruptive phases that took place in the 19th and 20th centuries.

Halemaumau crater is a deep pit within Kilauea caldera. During some past eriptive phase the pit filled and overflowed with lava. Numerous fularoles are still active within the crater.

Ropey lava flows such as this are known as pahoehoe.  It is caused when the path of very fluid basaltic lava becomes blocked and the flow begins to override itself. The high fluidity is caused by a high water content. When the water is degassed, the flow turns into the clinkery aa type.

On January 8, 1983 the new eruptive phase spread out all along the East Rift Zone of Kilauea. Output of sulfur dioxide, hydrogen sulfide, and other gases was too intense to permit inspection of the remote eruption on foot so we hired a small airplane to make an overflight of the eruption.

Lavas from the eruption eventually crept toward the edge of the Holei Pali, a fault scarp, and flowed over the edge toward the sea. The lighter gray lavas are pahoehoe while the black ones are aa.

By 1990, several fingers of the flow had crossed the Chain of Craters Road. It has been closed to through traffic ever since. Visitors are allowed, however, to hike back to the site where lava is entering the ocean.

Enormous amounts of steam are generated when molten lava enters the sea. Many hectares of new land have been added to the island as the flows prograde outward. Growth is accompanied, however, by the occasional collapse of these new lava benches into the sea. These events and frequent phreatic (steam) explosions prevent onlookers from getting too close to the ocean entry site.

The accretionary events currently taking place along Kilauea's south flank have happened many times before in the ongoing struggle between the island and the sea. With each eruptive event that enters the sea a new peinsula is built into the water. As soon as the eruption ends the waves begin to wear it away. Often this results in the formation of a sea arch such as the one seen here.  The arch will eventually fall. Without  volcanic activity, the island will eventually disappear beneath the waves.