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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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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December 22, 2020

Overnight Fissure Activity Halema‘uma‘u Crater, Kīlauea

Two fissure vents feed a growing lava lake at the bottom of Halema‘uma‘u crater. A preliminary calculation of volume suggests that since the start of the eruption on December 20, 2020, approximately 8-10 million cubic meters of lava have been erupted. This is equivalent to over 2 billion gallons, the volume of 3,000 Olympic-sized swimming pools.

December 22, 2020

Fissures, Lava Lake, Wind Vortex at Halema‘uma‘u, Kīlauea

Fissures Feed a Lava Lake at Halema'uma'u, at Kīlauea Volcano's Summit. Since fissures opened on December 20, 2020 in Halema'uma'u crater, USGS–Hawaiian Volcano Observatory scientists have maintained a 24-hour watch from the rim, taking measurements and making visual observations. This video captures fountaining activity at the two active vents during the early morning

geophysicist deploys campaign GPS sites on the Kīlauea caldera floor
December 21, 2020

Geophysicist deploys campaign GPS sites on the Kīlauea caldera floor

A Hawaiian Volcano Observatory geophysicist deploys campaign GPS sites on the Kīlauea caldera floor in Hawai‘i Volcanoes National Park to measure changes in ground motion. The gas plume from the summit eruption within Halema‘uma‘u crater is visible in the background. USGS photo taken by A. Ellis on December 21.

December 21, 2020

Lava Returns to Halema'uma'u: Timelapse Captures, December 20-21, 2020

Lava Returns to Halema'uma'u, as captured in this timelapse from the K2cam, located at the HVO Observation Tower (Kīlauea Volcano). Timelapse is from December 20, 2020, 5:50 a.m. to December 21, 2020, 11:57 p.m. The K2cam is a research camera mounted in the observation tower at the previous Hawaiian Volcano Observatory building on the rim of Kīlauea caldera within Hawai'i

Color photograph of scientists making measurements
December 21, 2020

Scientists use a FTIR spectrometer

On the morning of Dec. 21, Hawaiian Volcano Observatory gas scientists use a FTIR spectrometer on the rim of Halema‘uma‘u crater. The FTIR measures the composition of the gases being emitted during Kīlauea Volcano's ongoing summit eruption by measuring how the plume absorbs infrared energy. The plume being generated by the ongoing eruption is sulfur-dioxide (SO2) rich, but

Map of lava lake depth
December 21, 2020

December 21, 2020—Kīlauea summit eruption lava lake depth map

Aerial visual imagery collected during an overflight of Kīlauea Volcano's summit just after 11 a.m. HST on December 21, 2020, was used to create a preliminary topographic model. When compared to pre-eruption topographic models, it shows that the bottom of Halema'uma'u crater has been filled by over 100 m (yd) of lava. Map by B. Carr.

Color photograph of eruption and plume
December 21, 2020

Kīlauea summit eruption and plume on Dec. 21, 2020

Photo shows volcanic gases from the current eruption at Kīlauea’s summit being transported southwest into the closed area (left side of photo). This photo also shows the cracks, cliffs, and uneven ground surfaces present in the closed area of Hawai‘i Volcanoes National Park. USGS photo by K. Mulliken on 12/21/2020. 

Animation showing bright orange lava erupting at night and flowing into a pool of lava.
December 21, 2020

Lava Erupting at Kīlauea (Dec 2020)

This animation shows lava erupting from Kīlauea Volcano on Dec 20, 2020. 

Aerial view of the Kīlauea summit eruption showing active fissures and flowing lava.
December 21, 2020

Aerial view of the Kīlauea summit eruption

Aerial view of the Kīlauea summit eruption from a Hawaiian Volcano Observatory overflight at approximately 11:20 a.m. HST. The two active fissure locations continue to feed lava into the growing lava lake in Halema‘uma‘u crater, with the northern fissure (pictured right) remaining dominant.

December 21, 2020

Fissure Vents Feed New Lava Lake at Halema'uma'u, Kīlauea (Dec 2020)

Lava returns to Halema'uma'u, at the summit of Kīlauea Volcano. During a helicopter overflight on December 21, 2020, at approximately 11:30 AM HST, Hawaiian Volcano Observatory scientists observed the northern fissure and lava cascade (right) supplying the majority of the lava into the lake, while the western (left) fissure was feeding several small channels that were

Close-up of tephra sample from Kilauea eruption 12/21/20
December 21, 2020

Close-up of tephra sample from Kilauea eruption 12/21/20

A close-up photo of a tephra sample taken from one of the sample collection buckets. These small fragments of volcanic glass include Pele’s Hair and Pele’s tears—formed during lava fountaining—which are light weight and can be wafted downwind with the plume. 

Geologist labels tephra samples Kilauea eruption 12/21/20
December 21, 2020

Geologist labels tephra samples Kilauea eruption 12/21/20

HVO geologist retrieves and labels tephra samples from collection buckets placed downwind of Halema‘uma‘u crater after the onset of the Kīlauea summit eruption. These samples are collected for petrological analysis to gain further insight into the eruption dynamics.

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graphic of how a collapse/explosion event sequence
June 28, 2018

At the summit of Kīlauea Volcano, Halema‘uma‘u has changed dramatically since early May 2018. As the crater walls and inner caldera slump inward, the depth of Halema‘uma‘u has more than tripled and the diameter has more than doubled.

June 28, 2018

These FAQs will help answer some of the most commonly asked questions about the nature of Kīlauea's summit activity and the numerous earthquakes occurring in the area.

June 27, 2018

This "Cooperator Report to the U.S. Coast Guard" addresses hazards associated with the Kamokuna ocean entry, active July 2016—November 2017, on KILAUEA's south flank

Subsidence of caldera floor impedes ability of NPIT GPS station to ...
June 25, 2018

On June 18, Hawaiian Volcano Observatory staff said a sad goodbye to a GPS instrument that had faithfully recorded over 95 m (310 ft) of downward motion of the floor of Kīlauea caldera before losing radio contact.

This means that Mauna Loa is now considered to be at a normal, background level of activity. (More information about alert level
June 22, 2018

For more than six months, earthquakes at Mauna Loa have diminished and deformation has slowed, indicating that the volcano is no longer at an elevated level of unrest. On June 21, 2018, the Hawaiian Volcano Observatory (HVO) lowered the alert level from ADVISORY to NORMAL, and lowered the color code from YELLOW to GREEN.

the sun is illuminating the volcanic gas plume from behind
June 17, 2018

When volcanic gases are released into the atmosphere, resulting plumes sometimes appear to have a faint color. Is this color indicative of a certain gas present? Answering this question requires describing what makes a plume visible in the first place.

Close-up photograph of stem, leaves and flower buds of haha plant
June 8, 2018

Caly isn't likely to wonder off off, but with a remote camera and monitoring station online 24-hours a day, USGS and partners at the State of Hawai‘i Division of Forestry and Wildlife, University of Hawai‘i, and the USFWS can learn how an extremely rare plant is responding to changes in environmental conditions.

low magnification photo shows ash particles
June 7, 2018

Small explosions that produce ashfall from Kīlauea Volcano's summit are not new. However, the mechanism, vigor, plume heights, and extent of ash fallout from the current explosive activity within Halema‘uma‘u are.

Halema‘uma‘u at the summit of Kīlauea Volcano captured from an Unmanned Aircraft Systems
June 1, 2018

With the current activity at the volcano's lower East Rift Zone and summit, it's an understatement to say that Kīlauea has been making worldwide headlines the past month.

May 29, 2018

Deflation at Kīlauea's summit has caused up to 1.5 meters (about 5 feet) of subsidence, which has stressed the faults around and within Kīlauea Caldera. 

pockets of natural gas from the burning plant material can ignite
May 24, 2018

Numerous hazards are associated with active lava flows, and USGS Hawaiian Volcano Observatory scientists have written about many of them in past Volcano Watch articles. However, it's been a while since one particular hazard—so-called "methane explosions"—has been addressed.

May 24, 2018

An explanation of magma movement from Kīlauea's summit through the volcano's East Rift Zone and to the eruption site(s) in lower Puna.