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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Poster laid out with photos, images, and text.
December 31, 2005

Mud Damages Hawaiian Coral Reefs

Large-scale poster describing USGS work.

Scientists from the USGS, the University of Hawaiʻi (UH), and the University of Washington (UW) are studying the coral reefs near several Hawaiian islands. Using air photos, satellite photos, underwater photos, and underwater instruments, we've found that mud washed offshore by large storms can damage coral reefs. Corals need

November 28, 2005

Lava Delta Collapse at East Lae‘apuki

At 11:10 in the morning on November 28, 2005, the lava delta at the East Lae‘apuki ocean entry, on Hawai‘i's southeastern coast, began to collapse into the ocean. This was not a catastrophic failure of the 13.8-hectare delta, but instead occurred by piecemeal calving of the front of the delta over a period of just less than 5 hours. The collapse removed nearly the entire

Nene adults and goslings in a grassy field
November 27, 2005

Nene adults and goslings

A mating pair of adult nēnē (Branta sandvicensis) keep a close watch on three young goslings. An endangered species and the state bird of Hawai‘i, nēnē are the last remaining species of Hawaiian goose.    

Kīlauea Volcano's east Lae‘apuki lava delta after 70-100 m (230-330...
August 27, 2005

Kīlauea's east Lae‘apuki lava delta after 70-100 m (230-330 ft) lon...

Embayment of lava delta shows result of collapse. The initial collapse was large enough to send waves washing over much of the east half of the delta, because visibility was completely lost for almost 20 minutes, due to a steam white-out. Note rocky debris hurled by the waves onto the delta surface in foreground.

Kīlauea Volcano's east Lae‘apuki lava delta pictured hours before i...
August 26, 2005

Kīlauea's east Lae‘apuki lava delta pictured hours before it collap...

Kīlauea Volcano's east Lae‘apuki lava delta pictured hours before it collapsed into the sea over a 90-minute period. White plume marks location of lava entering sea fed by a lava tube within delta.

Lava spilling over sea cliff starts to build new lava delta, Kīlaue...
August 23, 2005

Lava spilling over sea cliff builds new lava delta, Kīlauea

pāhoehoe lava spilling over sea cliff on south coast of Kīlauea Volcano starts to build a new lava delta. Only three days old, the delta grows slowly as lava spreads over fragmented debris and flows that have accumulated on the steep submarine slope.

Tephra-jet explosion at leading edge of an active lava delta, Kīlau...
August 19, 2005

Tephra-jet explosion at leading edge of an active lava delta, Kīlauea

Explosive interaction between lava and seawater blasts a tephra jet consisting of steam, hot water, black tephra, and molten fragments into the air. Such explosions are typically directed toward the sea, but many explosions also send a shower of lava more than 10 to 20 m (33 to 66 ft) inland. Tehpra jets are the most common type of lava-seawater explosion, and typically

Active lava delta on the south coast of Kīlauea Volcano, Hawai‘i...
August 12, 2005

Active lava delta on the south coast of Kīlauea, Hawai‘i

Active lava delta at East Lae‘apuki on the south coast of Kīlauea Volcano. White gas plume (right) marks location of lava entering the sea through a lava tube whose location is shown by blueish fume (left and center). In early August 2005, the delta encompassed an area of about 12 hectares (30 acres). On August 27, about 4.5 hectares (11 acres) of the delta collapsed into

Radio telemetry tower on Mauna Kea
July 5, 2005

Radio telemetry tower on Mauna Kea

A VHF radio receiving tower is set up on the slopes of Mauna Kea volcano on Hawai‘i Island, Hawai‘i. This setup allowed researchers to track radio tagged palila over large areas to determine where they were spending their time. 

May 10, 2005

Lava Pond Spattering and Overflow at the MLK Vent

(May 10, 2005, 16:20:29 to 18:30:29) After the collapse of the main spatter cone at the MLK vent (see movies "Spatter cone collapse at the MLK vent"), a small lava pond was visible within the new pit. At times, the level of the lava pond rose abruptly, overflowing the rim of the pit. This movie is an example of this and shows the lava surface rising suddenly to overflowing

May 2, 2005

Spatter Cone Collapse at MLK Vent

(May 2, 2005, 05:30:04 to 07:30:02) During spring 2005, activity at the MLK vent, on the southwestern flank of the Pu‘u ‘Ō‘ō cone, changed from a period of construction to one of destruction. This was highlighted by the collapse of the main MLK spatter cone. The drain-back of lava beneath the spatter cone, following lava extrusion, apparently removed support of the

May 2, 2005

Spatter Cone Collapse at MLK Vent

(May 2, 2005, 02:30:28 to 07:30:37) The spatter cone collapse described in the movie below was also recorded by a time-lapse camera on the west flank of the Pu‘u ‘Ō‘ō cone. This camera was located about 70 meters from the MLK vent and recorded two pulses of lava effusion from the vent before collapse. The first, and larger, pulse of effusion was abruptly terminated by a

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September 13, 2001

The four youngest vents on West Maui erupted between 610,000 and 385,000 years ago. These newly determined radiometric ages remind us that sporadic small eruptions are possible on Hawaiian volcanoes even as they verge on extinction.

September 6, 2001

Nothing is constant except change. On August 17 the Kalapana road was reopened, allowing visitors access to a short trail and fine view point overlooking the active ocean-entry bench. Two weeks later, a narrow lava flowcrossed the road just east of the trailhead, and the road was closed. How did this happen, will it happen again, and what can be done about it?

August 30, 2001

Several decades ago, a person who had an overly active imagination might have been described as being "out in the ozone." Now just where would that be? Well, ozone (O3) exists in two distinct layers in the Earth's atmosphere and is considered "good" or "bad," depending on where it is. The US EPA has coined a maxim to help us remember: "good up high - bad nearby."

August 23, 2001

What is the summit elevation of Mauna Loa? 13,677 feet (4168.7 m) according to the 1994 Hawai`i Volcanoes National Park brochure; 13,679 feet (4169.4 m) according to the 1998 Atlas of Hawai`i; and 4,169 meters, which equals 13,678 feet, on the 1996 Geologic Map of the Island of Hawai`i. Who is right? Perhaps all?

August 16, 2001

At 2:00 p.m. on Friday, August 17, the County of Hawai`i officially opened to the public a new viewing area of the current eruptive activity. The viewing area overlooks the spectacular seascape of the lava bench and accompanying black sand beach at the ocean entry east of Kupapa`u.

August 9, 2001

What's the difference between a bench and a boardwalk? Both offer a view of the sea, but while the latter is a pleasant place for a stroll, a walk on the lava bench can kill you.

August 2, 2001

Every few months HVO receives a phone call from a concerned citizen explaining that steam is billowing from a new hole in a yard or pasture. Is this foretelling the start of an eruption?

July 26, 2001

Surfers of our Hawaiian Volcano Observatory (HVO) web site might have noticed that, earlier this year, we rolled out a modified web presentation of earthquake activity in Hawai`i. An "After Dark in the Park" evening talk at Hawai`i Volcanoes National Park in June also described our new web pages and their operation.

July 19, 2001

Every so often we receive a number of inquiries from anxious people in Kona about a possible eruption of Hualālai Volcano. The latest spate of questions is apparently being triggered by a personal web site that contains inaccurate information about the volcano. We hope to dispel the rumors by presenting the results of our ongoing observations.

July 12, 2001

The ground surface subsided abruptly about six weeks ago at Pu`u `O`o, Kīlauea Volcano's active cinder-cone vent. Gaping cracks opened around the edges of the subsidence zone, centered on the southwest edge of the cone. A collapse pit about 30 m (100 ft) in diameter and 15 m (50 ft) deep nibbled into the cone's margin. 

July 5, 2001

A visitor recently asked, "Does Kīlauea erupt more often at the summit or along its two rift zones?" Let's try to answer that question.

June 28, 2001

A common sight this time of year, particularly in Puna and the National Park, is a bright yellow tripod topped with a white disk. Usually seen standing by the side of the road, these instruments are Global Positioning System (GPS) antennas, which scientists at the Hawaiian Volcano Observatory use to measure small ground motions.