Unified Interior Regions


The Pacific Region has nine USGS Science Centers in California, Nevada, and Hawaii. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions.

States L2 Landing Page Tabs

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Red hot lava erupts vertically in the air from a cone of black, hardened lava
September 6, 1983

Low fountain of lava from Pu'u 'O'o, Kilauea Volcano, 1983

Low fountain, approximately 50 meters high, from Pu'u 'O'o on Hawai'i Island's Kilauea Volcano (viewed from the north). Lava issuing from the breach in the northeast rim of the crater produced an 'a'a flow that extended more than 4 kilometers. Eruption episode 8.

Red hot lava fountaining 100 meters into the air from a cone of hardened, black lava
September 6, 1983

100-meter lava fountain, Kilauea Volcano, 1983

Pu'u 'O'o fountain approximately 100 meters high during eruption episode 8 on Hawai'i Island's Kilauea Volcano. Dark clots of spatter land near the base of the fountain, contributing to the growth of the cone. Less dense cinder, visible in the upper right, is carried downwind of the cone.

egg-shaped ball of red-hot lava with a blackened crust sitting on a bed of grass
July 23, 1983

Lava ball, Kilauea Volcano, 1983

Accretionary lava ball comes to rest on the grass after rolling off the top of an 'a'a flow in Royal Gardens subdivision on Hawai'i Island's Kilauea Volcano. Accretionary lava balls form as viscous lava is molded around a core of already-soldified lava.

Flat-topped cinder cone with red-hot lava splattering out of the top and cascading down the sides.
June 29, 1983

Pu'u 'O'o cinder-and-spatter cone, Kilauea Volcano, 1983

View at dusk of the young Pu'u 'O'o cinder-and-spatter cone, with fountain 40 meters high, on Hawai'i Island's Kilauea Volcano (episode 5).

A stream of red hot lava arcs into the air and splatters down on cooler, black lava flows
February 25, 1983

Arching fountain of lava, Kilauea Volcano, 1983

Arching fountain of lava approximately 10 meters high issuing from the western end of the 0740 vents, a series of spatter cones 170 meters long, south of Pu'u Kahaualea on Hawai'i Island's Kilauea Volcano (episode 2). Episodes 2 and 3 were characterized by spatter and cinder cones, such as Pu'u Halulu, which was 60 meters high by episode 3.

Photo showing a dozen narrow, blackened tree trunks with a crusted layer of black lava clinging to the bottom of each tree
January 7, 1983

Forest of lava trees, Kilauea Volcano, 1983

Forest of lava trees resulting from eruption of a 1-km-line of vents east of Pu'u Kahaulea on Hawai'i Island's Kilauea Volcano. The bulbous top of each lava tree marks the high stand of the lava flow as it spread through the trees. As the fissure eruption waned, the flow continued to spread laterally; its surface subsided, leaving pillars of lava that had chilled against

Lava fountains erupting from fissures, Kīlauea Volcano, Hawai‘i...
January 5, 1983

Lava fountains erupting from fissures, Kīlauea, Hawai‘i

Lava fountains erupt from fissures during the first week of the Pu‘u ‘Ō‘ō eruption south of Pu‘u Kahaualea, approximately 2.4 km (1.5 miles) northeast of where subsequent eruptions built the Pu‘u ‘Ō‘ō cone. The early fissures cut through old forested lava flows in a remote section of Kīlauea's east rift zone. Note single 'ohi'a tree burning in front of the fissures.

Submerged coconut grove at Halapē after 1975 earthquake, Kīlauea Vo...
December 4, 1975

Submerged coconut grove at Halapē after 1975 quake, Kīlauea

A M 7.7 earthquake on November 29, 1975, was located beneath the south flank of Kīlauea. Along the south coast of Kīlauea at Halapē, 30 km southwest of the earthquake, the ground subsided by as much as 3.5 m (11.5 ft), which left a grove of coconut palms standing in water about 1.2 m (4 ft) deep and the new shoreline about 100 to 150 m (110 to 164 yd) inland from its

Earthquake-damaged road, Hawai‘i Volcanoes National Park, Kīlauea V...
November 29, 1975

Earthquake-damaged road, Hawai‘i Volcanoes National Park, Kīlauea

Ground cracks along Crater Rim Drive in Hawai‘i Volcanoes National Park caused by the M 7.7 earthquake on November 25, 1975. The cracks resulted from slumping of the ground toward the rim of Kīlauea Crater, the edge of which is left of the guardrails.

Mauna Loa 1975 eruption. Lava fountains up to 20 m (65 ft) high eru...
July 6, 1975

Mauna Loa 1975 eruption. Lava fountains up to 20 m (65 ft) high eru...

Mauna Loa 1975 eruption. Lava fountains up to 20 m (65 ft) high erupted from fissures on the north flank of the volcano early Sunday morning, July 6, 1975.

South flank of Kīlauea Volcano consists of several large scarps for...
June 24, 1971

South flank of Kīlauea consists of several large scarps formed by r...

Seaward sliding of Kīlauea's south flank over many thousands of years has resulted in large ground displacements along shallow faults that break the surface, as shown by the cliffs ("pali" in Hawaiian) seen here. Most of the movement along the faults occur during sudden slip that cause large earthquakes. Scientists recently discovered that the south flank also moves

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April 12, 2001

Here's a riddle for you—which large land holder on the Big Island condemns property at will, holds liens on large parts of the island, and doesn't pay a cent of taxes?

April 5, 2001

Late on March 30, a visiting geology student from Oregon fell about 12 m (40 feet) into a crack in the ground between Crater Rim Drive and the rim of Kīlauea's caldera, opposite Kīlauea Military Camp. He and a companion had seen a dark area free of vegetation. Lacking a flashlight, they couldn't tell what it was.

March 29, 2001

Nearly on the other side of the planet, the Big Island has a sister, older by at least a couple of million years: Reunion Island, built in the same way as ours.

March 22, 2001

The summits of volcanoes are part of an ever-changing landscape. The summit of Mauna Loa has undergone considerable change in the short period since the first explorers began documenting their visits to the volcano.

March 15, 2001

The U.S. Geological Survey's Hawaiian Volcano Observatory currently operates a network of 65 seismic stations. Signals from each station, including the four on Maui, are radio-telemetered to HVO and recorded.

March 11, 2001

Haleakalā Crater is a large erosional valley at the summit of Haleakalā volcano, East Maui. It formed after the rimrock lava flows were erupted around the top of the volcano about 145,000 years ago, give or take about 10,000 years.

March 1, 2001

March 5 is the 36th anniversary of one of Kīlauea's most important eruptions—the 1965 eruption that formed Makaopuhi lava lake. It was the fifth of six rift eruptions between the summit eruptions of 1961 and 1967-68, and it was the longest and largest.

February 22, 2001

Several scientists from the Hawaiian Volcano Observatory and the University of HAW‘A‘āII attended the Cities on Volcanoes II conference held in Auckland, New Zealand, last week. Auckland is truly a city on a volcano—48 volcanoes, to be precise, ranging in age from 40,000 years to a startling 600 years.

February 15, 2001

Whenever a large, destructive earthquake occurs anywhere in the world, such as those in Sumatera and El Salvador on January 13, there is an agency within the U.S. Geological Survey responsible for disseminating information about its location and magnitude on a rapid basis 24 hours a day--the National EarthquakeInformation Center (NEIC).

February 8, 2001

The tiny, crescent-shaped island of Molokini lies 4.2 km (3 miles) offshore of Haleakalā volcano, East Maui. Molokini is a volcanic cone that rises about 150 m (500 ft) from the submarine flank of Haleakalā to a summit only 49 m (162 ft) above sea level.

February 1, 2001

Many readers have visited Halema`uma`u, but how many have turned the other way and walked across Crater Rim Drive? Within 800 m (half a mile) roundtrip, you can see some very different features from those near Halema`uma`u, generally without the sulfurous gas.

January 25, 2001

With east Hawai'i in the throes of "vog season" over the past several months, the National Park Service (NPS) and U.S. Geological Survey's Hawaiian Volcano Observatory (USGS - HVO) have collaborated on a new initiative designed to better protect the health of visitors and employees in Hawai'i Volcanoes National Park.