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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November 8, 2001

Everybody is familiar with ocean tides that cause the ocean level to go up and down, usually twice a day. We can go down to the beach and watch this tidal action along any coast in the world. On a global level, the ocean tides are actually waves whose crests are half a world apart and traveling from east to west. At most points on the globe, the tidal crest comes by about every 12.5 hours.

November 1, 2001

Most people know that volcanoes formed the Hawaiian island chain. Few realize, however, that the chain consists of two or more strands of volcanoes located along distinct but parallel curving pathways, variously called loci, lines, or trends. Multiple loci of volcanoes are intertwined to form one island chain.

October 25, 2001

Over the past several weeks, visitors to Kīlauea have been treated to views of spectacular surface lava flows cascading down the pali and a new ocean entry complete with a vigorously growing coastal bench.

October 18, 2001

Of the more than 30 eruptions of Mauna Loa in the last hundred years, the 1975 and 1984 eruptions are the first events for which we have detailed seismic and deformation data. Thus, we consider the 1975 and 1984 data sets important standards against which future unrest can be compared and interpreted.

October 11, 2001

Volcanologists have long known that when molten rock rises to within 2-10 km (1-6 miles) of the Earth's surface, the overlying ground is often pushed upward by at least several centimeters (inches), sometimes more than 1 m (3 feet).

October 4, 2001

"Volcano Watch" often responds to a question from an interested citizen. A resident of Makawao, Maui, asked about the stability of Kīlauea and whether its south flank could slide away during an eruption of Mauna Loa.

Close view of the lava falls in the image above shows cones of lava...
September 30, 2001

Spectacular lava drapery and falls at new Kamoamoa entry.

September 27, 2001

A few days before the long Labor Day weekend, Hawai'i County officials closed the newly opened Lava Viewing road because a surface lava flow was threatening to cross it. Fortunately, the lava flow stopped just after it crossed the road, and the road was reopened a few days later. For some, it was a revelation that this could happen so soon. Others realized it was business as usual.

September 20, 2001

Forty years ago, at 12:36 p.m. on September 21, a swarm of large, shallow earthquakes accompanied by strong harmonic tremor began to emanate from the vicinity of Napau Crater on the east rift zone of Kīlauea Volcano. A rapid deflation of the summit of Kīlauea occurred in conjunction with the earthquake swarm.

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."