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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April 22, 1999

After an earthquake felt by residents of Hawai`i County, we at the U S Geological Survey's Hawaiian Volcano Observatory are often asked what the earthquake means or indicates in terms of the volcano's behavior. It is beyond our ability to know the detailed implications of a single earthquake event for the complex and inter-related volcanic and tectonic processes that shape our island.

April 15, 1999

Boaters, hikers, pilots, and other outdoor enthusiasts can use hand-held Global Positioning System (GPS) receivers to locate themselves or to navigate to a point of known position. Volcanologists routinely use hand-held GPS receivers to map lava flows and other volcanic features. 

April 8, 1999

An ancient Japanese proverb says that the most recent disaster fades from memory just before the next one strikes. Recently our friend Garret Hew of East Maui Irrigation inquired about the great 1938 Maui earthquake. That's good news; that earthquake hasn't faded from memory yet.

April 1, 1999

It started innocently enough. The long-lived lava lake disappeared from Halema`uma`u on February 21. Seventy-eight earthquakes were recorded in March, many along Kīlauea's east rift zone as far as 45 km (27 miles) from HVO; one on the 29th was felt in Hilo.

March 25, 1999

Earth scientists know a lot about Mauna Loa above sea level but much less about it under water. Studies have naturally focused on the easily accessible island, where one can directly observe and sample rock exposures, gauge the time between eruptions, and trace evolutionary changes in the chemical makeup of the lava flows. 

March 18, 1999

One common saying in the real estate business is that location is everything. This is particularly true from both geological and biological standpoints here in Hawaii. The Hawaiian hot spot has produced one of the most isolated island chains in the world, with some benefits not often appreciated. One of them is the natural quarantine imposed by more than 3000 km (2,000 miles) of open ocean.

March 11, 1999

Kīlauea's summit magma chamber is connected to the rift-zone vents like a water tank linked by hose to an irrigation system. The hose comprises the dikes that lie at 3-4 km depth along the trace of the rift zones. 

March 4, 1999

Among the many tools earth scientists use, the measurement of gravity variations over the earth's surface is one of the most useful for studying Hawaiian volcanoes. You're surprised to hear that gravity is not a constant?

February 25, 1999

Some readers will know that the largest eruption in the world during the 20th century took place in Alaska in 1912, producing the Valley of Ten Thousand Smokes near Mount Katmai (13 cubic kilometers; 3.1 cubic miles). These same readers may also know that the second largest eruption of this century formed the caldera at Mount Pinatubo, Philippines, in 1991 (5.3 cubic kilometers; 1.3 cubic miles).

February 18, 1999

This past week, the U.S. Geological Survey's Hawaiian Volcano Observatory (HVO) hosted 68 Japan Broadcasting Company (NHK) personnel and associates. NHK is scheduled to transmit a live 90-minute program from HVO to Japan on Saturday, February 20. Kīlauea Volcano and HVO are featured to demonstrate the quality of high definition TV and to attract a large audience.

February 11, 1999

Imagine this scene: the crew at the Hilo Fire Department receives a call telling them to stand by because an arsonist is setting a fire. If the blaze warrants a response, the fire crew will be notified. In the volcano-monitoring business, we receive standby calls about four to six times a year.

February 4, 1999

During the past couple of months, those of us living in east Hawai`i have experienced several episodes of poor air quality, owing to disruptions of the northeasterly trade winds. The trades usually bring us rain (especially during the last two weeks!) but also sweep the air-polluting volcanic smog (vog) away from east Hawai`i.