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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Kamoamoa Eruption...
March 9, 2011

Map showing the extent of the active flows of the Kamoamoa eruption, which started on March 5, 2011.

Image: July 2007 Eruption--Quarry flow near-view map: July 27, 2010
February 4, 2011

Map showing a close-up view of flow field expansion over the past few days.

July 2007 Eruption—Flow Field Map...
February 4, 2011

Map showing the extent of the "July 2007 eruption", or Episode 58, flow field relative to surrounding communities.

Halema‘uma‘u Vent Map...
February 1, 2010

Map showing the location of the Halemaʻumaʻu Overlook vent, and subsequent closures due to the eruption.

Aerial view of Pu‘u ‘Ō‘ō and vicinity...
November 1, 2009

Aerial view of Puʻu ʻŌʻō and surrounding features. 

Episode 56 Map (with Seismicity)...
June 20, 2007

Map shows activity from Episode 56.

Map of flows from Pu‘u ‘Ō‘ō: September 12, 2003...
September 12, 2003

Map shows lava flows erupted during 1983-present activity of Pu‘u ‘Ō‘ō and Kupaianaha. Red colors, both dark and light, denote Mother's Day flow, which began erupting on May 12, 2002 and continues to the present. The darkest color represents flows active since January 21, 2003.

Pu‘u ‘Ō‘ō cone and surroundings as of July 2000...
July 1, 2000

Pu‘u ‘Ō‘ō cone and surroundings as of July 2000, showing the area covered (mauve color) by lava since February 1997 during episode 55. Inside the crater of Pu‘u ‘Ō‘ō, the "trough" is the drained lava pond of September–October 1999. The central portion of the trough was briefly filled with lava in February 2000.

Pu‘u ‘Ō‘ō cone and surroundings as of March 2000...
March 1, 2000

Pu‘u ‘Ō‘ō cone and surroundings as of March 2000 showing the area covered (dark gray) by lava since February 1997 during episode 55. Inside the crater of Pu‘u ‘Ō‘ō, the "trough" is the drained lava pond of September–October 1999.

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August 9, 2018

Lava Entering Ocean Near Isaac Hale Beach Park

Lava continues to enter the ocean near the Isaac Hale Beach Park on Kīlauea Volcano's lower East Rift Zone. Although lava output from fissure 8 remains low, the ocean entry was still active during HVO's helicopter overflight on August 9, 2018. Numerous small streams of lava were oozing into the ocean near Ahalanui, creating weak plumes of laze. The southern flow margin

Color photograph of volcanic vent
August 7, 2018

 Aerial view of the fissure 8 cone

Aerial view of the fissure 8 cone and spillway captured by Civil Air Patrol during their overflight on August 7, 2018. View is toward the south.

New outcrops make good geology
August 6, 2018

New outcrops make good geology

This aerial view of the western part of Kīlauea Volcano's caldera was taken on August 6, 2018. The down-dropped block is faulted about 120 m (400 feet) below the caldera floor. Many 19th-century lava flows are exposed in the fault scarps. Halema‘uma‘u (not visible) is to the left of this photo.

August 6, 2018

Overflight of Kīlauea Summit

Between mid-May and early August, 2018, the depth of Halema‘uma‘u more than tripled and its diameter more than doubled as magma from Kīlauea's shallow summit reservoir moved into the lower East Rift Zone. Evidence of subsidence is visible in this video, taken during an early morning helicopter overflight on August 6, 2018. Cracks and down-dropped blocks of the caldera 

August 6, 2018

Lava Fountaining at Fissure 8

During this morning's overflight, HVO geologists observed low levels of lava fountaining within the fissure 8 spatter cone and crusted lava in the spillway and channel downstream. The significance of this change is not yet clear. Eruptions can wax and wane or pause for days to weeks before returning to high levels of lava discharge. New outbreaks in the area of the active 

Hot, molten lava flows slowly into the ocean, and the temperature difference between lava and water is creating steam.
August 5, 2018

Viscous lava hits ocean water

A viscous pāhoehoe flow from Kilauea Volcano, Hawaiʻi , entering the ocean near Isaac Hale Beach Park on the morning of August 5, 2018.

August 3, 2018

Pāhoehoe Breakout

This lava, erupted from fissure 8 on Kīlauea Volcano's lower East Rift Zone, shows classic pāhoehoe behavior. Exposed to the air, the surface of the flow chills to form a thin crust that can be stretched or broken apart, forming pieces of crust that are "subducted" back into the molten interior. The main sound is wind noise, but crackles can also be heard as flakes of

color photograph of volcanic lava channel
August 3, 2018

Lava in the fissure 8 channel spillway

Lava in the fissure 8 channel spillway was fairly low this morning, with the lava in the channel moving at a

Color photograph of caldera
August 3, 2018

Halema‘uma‘u, taken from the northeastern caldera rim

Early morning photo of Halema‘uma‘u, taken from the northeastern caldera rim. Inward slumping of the crater rim and walls continues. Ash deposits from previous explosions and collapse events

Assessing the Functional Equivalency of Hawaiian fishponds
July 29, 2018

Assessing the Functional Equivalency of Hawaiian fishponds

Hawaiian fishponds were important cultural and economic resources for native Hawaiians as they were an important component of a sophisticated, integrated food production system. However, changing demographics and systems of land ownership resulted in a decline in the use and upkeep of Hawaiian fishponds throughout the 19th century. The cultural value of Hawaiian fishponds

fissures were characterized by low eruption rates
July 29, 2018

fissures were characterized by low eruption rates

During the first two weeks of Kīlauea Volcano's 2018 lower East Rift Zone eruption, fissures were characterized by low eruption rates and small flows. This was because the erupted lava originated from pockets of cooler, less fluid magma stored in the rift zone. Later fissures erupted hotter, more fluid magma, resulting in higher eruption rates and large, fast-moving lava

Color photograph of volcano summit
July 28, 2018

Kīlauea summit caldera 

This view across the summit caldera shows ground cracks (center) just north of Halema‘uma‘u. Rockfalls within the crater and along the caldera walls continue to stir up dust that can be seen here rising above the caldera rim.

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Drive along Saddle Road reveals outstanding volcanic geology...
November 16, 2017

Route 200, the Daniel K. Inouye Highway, crosses Humu‘ula Saddle, which separates Mauna Kea and Mauna Loa, the two largest volcanoes on the Island of Hawai‘i. This Saddle showcases outstanding volcanic geology and is easy to reach for "roadside geologists." 

Mauna Loa lava flows...
November 15, 2017

Lava flows, Pu‘u Pohaku‘ohanalei cone, Moku‘āweoweo's North Pit, Sulphur Cone area, and a video of Mauna Loa's summit caldera.

Roughly 500 meters (0.3 miles) north of the sea cliff, a new breako...
November 10, 2017

Ocean entry inactive; breakouts continue on delta and coastal plain

Amidst steam created by rain falling on the hot lava, another HVO g...
November 9, 2017

Scientists at the USGS Hawaiian Volcano Observatory routinely collect lava samples from Kīlauea and use the chemistry of these samples to infer the temperature of magma (molten rock below Earth's surface).

Activity at Pu‘u ‘Ō‘ō and on the 61g flow...
November 1, 2017

Activity at Pu‘u ‘Ō‘ō and on the 61g flow

USGS maps identify lava inundation zones for Mauna Loa...
October 26, 2017

Using detailed geologic mapping and modeling of how a fluid (in this case, lava) responds to surface topography, USGS-HVO constructed nine maps depicting 18 inundation zones on Mauna Loa. Each zone identifies a segment of the volcano that could erupt lava and send flows downslope. 

The episode 61g Kamokuna ocean entry was still active today (Octobe...
October 26, 2017

Lava breakouts continue on the coastal plain and on the delta

New USGS video about Kīlauea Volcano's summit eruption is now onlin...
October 19, 2017

The U.S. Geological Survey has produced a documentary, "Kīlauea Summit Eruption–Lava Returns to Halema‘uma‘u," to tell the story of the eruption, and to share imagery of the inaccessible lava lake with the public.

pāhoehoe breakouts on the coastal plain...
October 13, 2017

Pāhoehoe breakouts on the coastal plain

HVO geologists relocate a time-lapse camera on the rim of the west ...
October 12, 2017

Breakouts remain active on flow field, changes to ocean entry lava delta