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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Airplane landing field at Kīlauea Volcano strewn with blocks from s...
May 22, 1924

Airplane landing field at Kīlauea strewn with blocks from several e...

Prior to the eruption of 1924, this area was swept clean and used as a landing field for airplanes. This view looking toward the north rim of Halemaumau shows the air field littered with ballistic blocks from explosions in the 1924 eruption.

Explosion from Halemaumau at Kīlauea Volcano as viewed from Uēkahun...
May 18, 1924

Explosion from Halemaumau at Kīlauea May 18, 1924.

This was probably the strongest explosion of the eruption. Rocks and debris fell among spectators southeast of Halemaumau, causing one fatality. A torrential downpour and an electrical storm followed.

Spectators flee explosion from Halemaumau at Kīlauea Volcano, 1114 ...
May 18, 1924

Spectators flee explosion from Halemaumau at Kīlauea, May 18, 1925

Acting HVO director Ruy Finch snapped this photograph of spectators running away as large blocks were tossed about 600 meters (2000 feet) onto an airplane landing field. Lorrin A. Thurston provided this description: "About three minutes later with a sudden dull roar a column of inky black eruption cloud shot upward from the pit and great masses of gray ash rolled out from

Park superintendent Thomas Boles after a narrow escape at Kīlauea V...
May 14, 1924

Park superintendent Thomas Boles after a narrow escape at Kīlauea, ...

Boles poses on the grounds of the Volcano House hotel with the Halemaumau eruption plume in the background. He fell cutting his hands and a knee while fleeing an explosion the day before. After his close call the superintendent barred all public access within two miles of Halemaumau.

Explosion at Halemaumau as seen from Uēkahuna Bluff, at Kīlauea Vol...
May 13, 1924

Explosion at Halema‘uma‘u as seen from Uēkahuna Bluff, at Kīlauea, ...

Eight persons, including newspaper and movie men observing the scene at Halema‘uma‘u, were caught in a rain of hot rocks from this explosion. The rocks emitted hissing sounds as hot gas, mainly steam, escaped from them. Park superintendent Thomas Boles was knocked down twice by this bombardment.

Observer examines boulder ejected from Halemaumau, at Kīlauea Volca...
May 11, 1924

Boulder ejected from Halemaumau, at Kīlauea, May 11, 1925

On May 11, Ruy Finch and W.O. Clark visited Halemaumau and found a rock fragment weighing about 180 kg (400 pounds) that had been thrown 60 meters (200 feet) from the rim of the crater.

One of the first explosion clouds from Halemaumau, at Kīlauea Volca...
May 10, 1924

First explosion clouds from Halemaumau, Kīlauea 1925

Later scientists at the Observatory listed May 10 as the first day of the eruptive series. Between this date and May 27, they carefully recorded all explosions, ballistic falls, electric storms, and muddy rains as well as earthquakes felt and recorded on seismographs.

Scientists looking into the bright glow of Mauna Loa's 1942 eruptiv...
April 28, 1924

Scientists looking into bright glow of Mauna Loa's 1942 eruptive ve...

Scientists looking into the bright glow of Mauna Loa's 1942 eruptive vent. Eruption occurred during WWII and was not publicized to prevent Japanese war planes from navigating to the island at night.

Black and white photographs of lava lakes in crater
December 11, 1919

Halemaʻumaʻu lava lake on December 11, 1919

Panorama photos taken of Halemaʻumaʻu lava lake on December 11, 1919, showing the outer ring-shaped lake, the ring-shaped island of tilted crusts along the inner edge, and the central lava lake at Kīlauea's summit. USGS photos by T.A. Jaggar. 

Eruption continues in Halema‘uma‘u at Kīlauea's summit

The KW webcam has documented the activity in Halema‘uma‘u crater wall at Kīlauea's summit. This photo comparison shows that activity has not changed significantly over the past several days. The first image (left) was taken on December 27, 2020, just after 6:30 a.m. HST, and the second image (right) was taken on January 1, 2021, just after 6:30 a.m. HST. The photos show

Profile of Mauna Kea showing inferred contact (dot-dashed line) bet...

Profile of Mauna Kea showing inferred contact (dot-dashed line) bet...

Profile of Mauna Kea showing inferred contact (dot-dashed line) between postshield-stage Hamakua Volcanics and underlying shield-stage lavas. Approximate contact with Laupahoehoe Volcanics dashed.

[M1cam] Mauna Loa's Northeast Rift Zone from HVO Observation Tower

This image is from a research camera positioned in the observation tower at the Hawaiian Volcano Observatory. The camera looks northwest toward the summit and Northeast Rift Zone of Mauna Loa.


The webcams are operational 24/7 and faithfully record the dark of night if there are no sources of incandescence or other lights. Thermal

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June 10, 1994

The eruption on Kīlauea's east rift zone continues with little change. The eruption has now been going for eleven and one-half years and shows no signs that the end is close.

June 3, 1994

On May 22 at 7:50 in the morning, the northern part of Hawaii Island was rattled by an earthquake with an estimated magnitude of 4.2.

May 27, 1994

Before the current activity on Kīlauea's east rift zone, the most long-lived rift eruption was that of Mauna Ulu, which began 25 years ago, on May 24, 1969.

The 1960 tsunami, Hilo...
May 20, 1994

Thirty-four years ago, on May 23, 1960, a tsunami destroyed much of downtown Hilo. Tsunami, or seismic sea waves, are generated in several ways, including by large submarine explosive eruptions, by landslides where rock slides into or beneath the sea surface, and by large earthquakes that displace rocks below sea level.

Kīlauea flows continue without interruption
May 13, 1994

The eruption along Kīlauea's east rift zone continues without interruption. Following the last pause in activity in the middle of April, the tube was reoccupied from the vent 51 and 53 areas adjacent to the Pu'u 'O'o cone to just above Paliuli, upslope from Kamoamoa.

May 6, 1994

Kīlauea is famous for eruptions of the type we are now experiencing--quiet effusion of lava that makes the eruption approachable. However, not all of Kīlauea's eruptions have been so passive and approachable.

Lava flow hazard map revisited...
April 29, 1994

A few weeks ago, several members of the Hawaiian Volcano Observatory staff presented information about volcanic hazards on Hawaii to the Hawaiian Beaches/Shores Community Association.

April 22, 1994

The past week has been eventful with many changes in the on-going eruption. The eruption stopped once again starting Thursday, April 14, in the afternoon, and lava had stopped entering the ocean by about 5 p.m.

April 15, 1994

The eruption along Kīlauea's east rift zone continues without interruption. The lava is erupting from two vents, which we call the episode 51 and 53 vents, located on the west and south flanks of the Pu'u 'O'o cone, and transported downslope in a long-lived tube system.

April 8, 1994

The U.S. Geological Survey's Hawaiian Volcano Observatory is located adjacent to the Thomas Jaggar Museum on the rim of Kīlauea caldera. The Observatory was founded in 1912 as a laboratory of the Massachusetts Institute of Technology by Thomas A. Jaggar, a pioneering volcanologist.

April 1, 1994

April 2 marks the anniversary of the largest earthquake to occur in the Hawaiian Islands in historic time. This great earthquake occurred in 1868 and had an estimated magnitude of 7.9.

March 25, 1994

Friday, March 25, marked the tenth anniversary of the last eruption of Mauna Loa Volcano. The 1984 eruption followed a nine-year period of quiescence. Roughly three years of increasing frequency of shallow- and intermediate-depth earthquakes preceded the eruption.