James G Moore

As a geologist with the U.S. Geological Survey, Dr. Moore has conducted pioneering research in the Sierra Nevada, Hawaii, the Philippines, the Mid-Atlantic Ridge, Mount St. Helens, Surtsey, and Lake Tahoe.

He mapped the geology of the southern Sierra Nevada in California including Sequoia and Kings Canyon National Parks and recognized a zonation of batholiths named the Quartz Diorite Line. The work revealed a major fracture system filled with igneous rock, the Independence Dike Swarm, which proved to be the key to dividing Sierran granites into two major age groups. The work also led to a model for the origin of orbicular granite and comb layering and defined the origin of giant K-feldspar crystals found in granodiorite plutons.

In 1961 he was posted as Scientist-In-Charge at the Hawaiian Volcano Observatory. He was first to recognize two giant submarine landslides on the flanks of the Hawaiian Ridge, and in 1962 served as Chief Scientist on the U.S. Coast and Geodetic Ship Pioneer, when some of the first ocean-floor photographs were taken of pillow lava. Analyses of this fresh lava quenched under pressure produced unique data on the initial gas content of magma. In the early 1970s he made the first scuba dives on active lava flows off Kilauea Volcano and documented the origin of pillow lava. In 1974 he participated in the FAMOUS project, a joint French-American diving program on the Mid-Atlantic Ridge, and completed six 9000-ft-deep dives in the submersible Alvin to map and sample young lavas. During the late 1980s he participated in the GLORIA project using sonar to map the Hawaiian Exclusive Economic Zone, which revealed several dozen massive submarine landslides on the Hawaiian Ridge. In 1995 he conducted similar sub-aqueous investigations of Lake Tahoe to determine the nature, age, and effects of a giant landslide in the lake basin.

In 1965 he was posted by President Johnson to work with Philippine scientists on the tragic explosive eruption of Taal Volcano, where giant dunes around the vent led to the concept of pyroclastic Base Surges. He also studied the ongoing 1968 explosive eruption of Mayon Volcano in the Philippines, measuring the velocity of hot block-and-ash avalanches. During 1979 he helped drill Surtsey volcano, which had grown offshore from Iceland in 1963-1967. The core revealed the nature of secondary hydrothermal minerals and that the volcano is underlain by two diatremes which extend far below the pre-volcanic ocean floor. He helped promote a 2017 redrilling of Surtsey Volcano, in which the results supported the diatreme hypothesis. In a 1999 Hawaiian drilling program, he studied core from a 3-km-deep drill hole on Mauna Loa, which showed the transition from subaerial- to submarine-erupted lava and established the degree of volcano subsidence.

During the 1980 eruption of Mount St. Helens, he measured the ongoing deformation of the volcano; afterward, he used photographs and military satellite images to define the exact timing of the May 18 events, determined the landslide volume, measured and described ash deposits, analyzed the formation of the eruption cloud, and mapped the first series of domes to fill the crater.

Science and Products

January 1, 2000

Geologic map of the Lone Pine 15' quadrangle, Inyo County, California

Oblique aerial view west across Owens Valley in Lone Pine 15' quadrangle. In distance, Sierra Nevada, capped by Mount Whitney (elev. 14,494 ft; 4,418 m). In middle distance, Alabama Hills, town of Lone Pine, and Owens River. In foreground, Kern Knob, at base of Inyo Mountains. Movement along Owens Valley Fault Zone, at base of Alabama Hills, caused great Lone Pine earthquake of 1872 (estimated Ric

Geology, Minerals, Energy, and Geophysics Science Center

January 1, 1994

Bathymetry of the southwest flank of Mauna Loa Volcano, Hawaii

Much of the seafloor topography in the map area is on the southwest submarine flank of the currently active Mauna Loa Volcano. The benches and blocky hills shown on the map were shaped by giant landslides that resulted from instability of the rapidly growing volcano. These landslides were imagined during a 1986 to 1991 swath sonar program of the United States Hawaiian Exclusive Economic Zone, a co

Natural Hazards Mission Area, Volcano Hazards Program, Volcano Science Center

January 1, 1994

Bathymetry of the west-central slope of the island of Hawaii

This map shows the topography of a small part of the subaerial western part of the Island of Hawaii as well as modern multibeam bathymetry of the west submarine flank, which covers a total area of about 8,500 km2 ( see index map). The map area includes part of the submerged flanks of the active Mauna Loa and Hualalai Volcanoes, which last erupted in 1984 and 1801 respectively. The steep and irregu

January 1, 1993

Bathymetry of southern Mauna Loa Volcano, Hawaii

Manua Loa, the largest volcano on Earth, lies largely beneath the sea, and until recently only generalized bathymetry of this giant volcano was available. However, within the last two decades, the development of multibeam sonar and the improvement of satellite systems (Global Positioning System) have increased the availability of precise bathymetric mapping. This map combines topography of the sub

Natural Hazards Mission Area, Volcano Hazards Program, Volcano Science Center

January 1, 1981

Physiographic diagrams of the May 18, 1980, landslide-eruption of Mount St. Helens, Washington

This sequence of diagrams shows the complex series of events that culminated in the catastrophic eruption of Mount St. Helens on the morning of May 18, 1980.

Natural Hazards Mission Area, Landslide Hazards Program, Geologic Hazards Science Center, Mount St. Helens

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government

James G Moore

Professional Experience

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Abstracts and Presentations

Science and Products

Non-USGS Publications**

Science and Products

Non-USGS Publications**