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.

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Ash-rich plume rising from Halema‘uma‘u Crater, Kīlauea Volcano 5 d...
March 24, 2008

Ash-rich plume rising from Halema‘uma‘u, Kīlauea 5 days after the f...

View of ash-rich plume rising from a new vent in Halema‘uma‘u Crater in Kīlauea Caldera 5 days after the first explosion from the vent occurred on March 19, 2008. The ash is turning the formerly white steam and gas plume a dusty-brown color. Note the ash fallout down-wind of the plume. Earlier in the day, geologists reported finding Pele's hair, Pele's tears, and spatter

March 19, 2008

10th anniversary of Kīlauea volcano's summit eruption

Today marks the 10th anniversary of the eruption within Halema‘uma‘u at the summit of Kīlauea Volcano. When the vent first opened on March 19, 2008, it formed a small pit about 115 feet (35 m) wide. Over the past decade, that pit (informally called the "Overlook crater") has grown into a gaping hole about 919 feet by 656 feet (280 x 200 m) in size. Click on the above

HVO technicians working on seismic station at summit of Kīlauea Vol...
February 18, 2008

HVO technicians working seismic station at summit of Kīlauea

HVO technicians install a solar-powered seismic station near the summit of Kīlauea Volcano to monitor earthquake activity. The seismic data is transmitted via radio signal directly to the observatory, where the data is initially analyzed by automatic computer programs and then examined in greater detail by a seismologist. Mauna Loa Volcano in background.

Image: Vog from Kilauea
January 31, 2008

Vog from Kilauea

The rim of Kīlauea Volcano’s summit caldera, normally clear on trade-wind days (left), became nearly obscured by vog (right) on some non-trade wind days beginning in 2008, when sulfur dioxide emissions from the volcano’s summit increased to unusually high levels. (This photo has been edited.)

January 26, 2008

TEB rootless shield flank failure

(January 26, 2008, 10:50:12 to 19:12:16) Perched lava ponds often formed atop the rootless shields built by the "Thanksgiving Eve Breakout" (TEB) lava flow. This movie shows the failure of the flank of a rootless shield on January 26, 2008, and the release of the lava contained within the perched lava pond at its summit. The inner wall of the perched lava pond come into

Image: Hawaiian Sunset
December 1, 2007

Hawaiian Sunset

Sunset over the ocean near Poipu, Kauai, Hawaii.

Attribution: Water Resources
December 1, 2007

TEB effusion and partial rootless shield flank failure

(December 1, 2007, 02:01:38 to 16:01:36) On November 21, 2007—the eve of the U.S. Thanksgiving holiday—Episode 58 changed dramatically. Lava, erupting from Fissure D into a perched lava channel, found an easier path to the surface and broke out from directly over Fissure D on what was, by then, the southern flank of the channel. This switch in the eruption led to the

November 15, 2007

Episodic spattering in the Episode 58 lava channel

(November 15, 2007, 09:00:15 to 13:00:15) Periods of overflow and levee construction at the Episode 58 lava channel were interspersed with periods when the lava level was below the channel rim. The lava surface within the lava channel commonly experienced repeated cycles of rise and fall, as shown here. During these cycles, the lava surface would rise slowly, then

September 20, 2007

Dome fountain over Fissure D vent of the Episode 58 eruption

(September 20, 2007, 05:00:03 to 09:00:03) As the Episode 58 lava channel developed, the upper end of the channel crusted over so that lava—extruding from the erupting fissure—flowed through a short tube before entering the channel. A small surge of lava on September 20, 2007, exceeded the carrying capacity of this tube and resulted in a small dome fountain through the

September 8, 2007

Long-term evolution of the Episode 58 lava channel

(September 8 to November 30, 2007) Within days of the onset of Episode 58 on July 21, 2008, activity localized on the easternmost eruptive fissure—Fissure D—and channelized lava began flowing to the northeast. Repeated overflows from the channel added slowly to its height, and the channel became perched up to 45 meters above the pre-existing lava surface. The images that

September 2, 2007

Aerial of eddy in channel near vent D

Aerial of eddy in channel near vent D

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January 31, 2002

At dawn on January 17, 2002, the residents of Goma, a city of 500,000 along the eastern border of the Republic of Congo, awoke to glowing red skies and falling ash. A large eruption of Mount Nyiragongo was underway, the first since 1977.

photo of lava
January 25, 2002

Rootless shields and hornitos along the main tube system

January 24, 2002

In one of the most ambitious volcano-monitoring efforts ever undertaken, scientists of the Alaska Volcano Observatory (AVO) are moving ahead with plans to increase the number of volcanoes they monitor with real-time geophysical instruments.

Map showing the lava flow from the 1859 Mauna Loa eruption
January 17, 2002

The 1859 eruption of Mauna Loa began in the evening of January 23. Following a brief summit eruption, an outbreak occurred high on Mauna Loa's northwest flank at the 3380 m (11,090 ft) elevation. The eruption ultimately destroyed a coastal village and fishponds at Wainanali`i and Kiholo, on the west coast of the island.

photo of lava
January 17, 2002

Views of 2220' rootless shield and 2300' growing hornito

photo of lava
January 11, 2002

A week's growth at the Kamoamoa bench and at a hornito

January 10, 2002

At this new calendar year, we welcome to our staff at the U S Geological Survey's Hawaiian Volcano Observatory our newest volcano watcher, Dr. Peter Cervelli.

photo of lava
January 6, 2002

Growth of west side of Kamoamoa bench

photo of lava
January 4, 2002

Views of south side of Pu`u `O`o, including Puka Nui

January 3, 2002

It is hard to believe that the Pu`u `O`o eruption became 19 years old on January 3. 

December 27, 2001

Haleakalā volcano, on Maui, is still in its postshield stage of volcanic evolution, as determined by 50 new isotopic ages. The volcano was long thought to have passed beyond that stage, with a lengthy eruptive lull lasting several hundred thousand years. The new ages show, however, that the lull does not exist and that lavaflows have erupted persistently during the past one million years.