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.

States L2 Landing Page Tabs

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December 3, 1993

The recent history of Kīlauea has been pieced together from geologic mapping and dating, Hawaiian oral histories, and written observations made following the arrival of Christian missionaries in the 1820s.

November 26, 1993

All of the events that we experience at Kīlauea—eruptions at the summit and on the rift zones, intrusions of magma that don't reach the surface, earthquake swarms that accompany eruptions and intrusion, and the large earthquakes that accompany growth of the volcano and trigger landslides—are responses by the pile of layered lava to the unrelenting pressure of magma rising from below.

November 19, 1993

Ten years ago on November 16, residents of Hawai`i were awakened by an earthquake at 6:13 a.m. The earthquake had a magnitude of 6.6 and was located beneath the Ka`oiki Fault Zone between the summits of Mauna Loa and Kīlauea Volcanoes.

Eruption provides dramatic viewing...
November 13, 1993

The eruption from the episode 51 vents has continued without interruption since October 2. The flows crossed the Chain of Craters Road near Kamoamoa in Hawai`i Volcanoes National Park on November 7, covered part of the archaeological ruins and entered the sea during the evening of November 8.

November 12, 1993

The nearly 11-year-long eruption on Kīlauea's East Rift Zone continues with little change. An active lava pond circulates from west to east inside the Pu`u `O`o cone and produces a bright glow at night. Two vent areas adjacent to Pu`u `O`o are active, although both are now crusted over with cooled lava.

Island of Hawaii sits at the end of a long, old chain of 125 volcan...
November 5, 1993

The Hawaiian Islands form the young end of a chain of more than 125 volcanoes that stretch over 3,720 miles across the north Pacific Ocean.

October 31, 1993

Hawaiian volcanoes pass through a sequence of eruptive stages as they grow. There are three main types of lavas in Hawai`i which erupt during the different stages. These distinct lava types have different chemical compositions and physical properties.

Lo`ihi seamount swarms with earthquake activity...
October 22, 1993

Kīlauea Volcano continues to erupt from the episode 52 and 53 vents on the flank of the Pu`u `O`o cone on the East Rift Zone. For the past several weeks, the lava flow has been confined within a tube system that extends from the vent area to the coast at Kamoamoa.

Volcano mapping among most detailed on Earth...
October 15, 1993

Geologic mapping has come a long way since the first map accurately showing the locations of lava flows on the Island of Hawai`i was published by Stearns and Clark in 1930. A more detailed geologic map of the entire island was produced by Stearns and McDonald in 1946. 

How does East Hawaii get vog?...
October 10, 1993

Over the past several weeks, many east Hawaii residents have noticed the high frequency of days with poor air quality. People traveling on Highway 11 through the Glenwood/Volcano area have encountered such severe bog that they had to turn on their car lights to navigate through the hazy gloom.

October 1, 1993

In a double handful of molten magma (weighing about a pound), there is less than a tenth of an ounce, by weight, of dissolved gas - roughly the same weight as a pinch of table salt. Yet this tiny amount of gas can drive spectacular lava fountains hundreds of feet into the air.

Kīlauea's East Rift Zone rests for a month...
September 24, 1993

The ongoing eruption on Kīlauea's East Rift Zone has continued with little change for the last month. Lava is erupting from both the episode 51 and 53 vents, both located on the southwest flank of the Pu`u `O`o cone.