Publications
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Thermodynamics of gas and steam-blast eruptions
Eruptions of gas or steam and non-juvenile debris are common in volcanic and hydrothermal areas. From reports of non-juvenile eruptions or eruptive sequences world-wide, at least three types (or end-members) can be identified: (1) those involving rock and liquid water initially at boiling-point temperatures (‘boiling-point eruptions’); (2) those powered by gas (primarily water vapor) at initial te
Authors
L.G. Mastin
Episode 49 of the Pu'u 'Ō'ō-Kūpaianaha eruption of Kilauea volcano-breakdown of a steady-state eruptive era
The Pu'u 'O'o-Kupaianaha eruption (1983-present) is the longest lived rift eruption of either Kilauea or neighboring Mauna Loa in recorded history. The initial fissure opening in January 1983 was followed by three years of episodic fire fountaining at the Pu'u 'O'o vent on Kilauea's east rift zone ∼19km from the summit (episodes 4–47). These spectacular events gave way in July 1986 to five and a h
Authors
M. T. Mangan, C. C. Heliker, T. N. Mattox, J. P. Kauahikaua, Rosalind Tuthill Helz
Mining the earth's heat in the basin and range
The Geothermal Program of the U.S. Geological Survey (USGS) is revisiting the Basin and Range Province after a hiatus of over a decade. The Basin and Range is a region of Neogene extension and generally high, but regionally and locally variable heat flow. The northern Basin and Range (Great Basin) has higher mean elevation and more intense Quaternary extension than does the southern Basin and Rang
Authors
John H. Sass
Cooling, degassing and compaction of rhyolitic ash flow tuffs: A computational model
Previous models of degassing, cooling and compaction of rhyolitic ash flow deposits are combined in a single computational model that runs on a personal computer. The model applies to a broader range of initial and boundary conditions than Riehle's earlier model, which did not integrate heat and mass flux with compaction and which for compound units was limited to two deposits. Model temperatures
Authors
J.R. Riehle, T.F. Miller, R. A. Bailey
Forest-killing diffuse CO2 emission at Mammoth Mountain as a sign of magmatic unrest
Mammoth Mountain, in the western United States, is a large dacitic volcano with a long history of volcanism that began 200 kyr ago and produced phreatic eruptions as recently as 500 ± 200 yr BP. Seismicity, ground deformation and changes in fumarole gas composition suggested an episode of shallow dyke intrusion in 1989–90. Areas of dying forest and incidents of near asphyxia in confined spaces, fi
Authors
C. D. Farrar, M. L. Sorey, William C. Evans, J. F. Howle, B.D. Kerr, B. M. Kennedy, C. -Y. King, J. R. Southon
Inclusions in Mount St. Helens dacite erupted from 1980 through 1983
Inclusions of plutonic, metavolcanic and volcanic rocks are abundant in dacite pumice and lava from the 1980–1986 eruption sequence at Mount St. Helens. Point counts of inclusions exposed in talus blocks from the dome from 1980 through 1983 show that inclusions form approximately 3.5 vol% of the lava. Eighty-five percent of the inclusions are medium-grained gabbros with an average diameter of 6 cm
Authors
C. Heliker
Factors influencing the height of Hawaiian lava fountains: implications for the use of fountain height as an indicator of magma gas content
The heights of lava fountains formed in Hawaiian-style eruptions are controlled by magma gas content, volume flux and the amounts of lava re-entrainment and gas bubble coalescence. Theoretical models of lava fountaining are used to analyse data on lava fountain height variations collected during the 1983–1986 Pu'u 'O'o vent of Kilauea volcano, Hawaii. The results show that the variable fountain he
Authors
E.A. Parfitt, L. Wilson, C. A. Neal
Can magma-injection and groundwater forces cause massive landslides on Hawaiian volcanoes?
Landslides with volumes exceeding 1000 km3 have occurred on the flanks of Hawaiian volcanoes. Because the flanks typically slope seaward no more than 12 °, the mechanics of slope failure are problematic. Limit-equilibrium analyses of wedge-shaped slices of the volcano flanks show that magma injection at prospective headscarps might trigger the landslides, but only under very restrictive conditions
Authors
R. M. Iverson
Roof-rock contamination of magma along the top of the reservoir for the Bishop Tuff
The Bishop Tuff, a Quaternary high-silica rhyolite in east-central California, is widely considered the type example of a vertically and monotonically zoned pyroclastic deposit that represents zoning in the source magma reservoir, inverted during the process of pyroclastic emplacement. However, the deposit of plinian pumice, which forms the base of the Bishop Tuff and represents the initial 10% or
Authors
W. A. Duffield, J. Ruiz, J.D. Webster
Strain accumulation north of Los Angeles, California, as a function of time, 1977–1992
No significant change in the rate of strain accumulation in a 40×120 km trilateration network spanning the San Gabriel mountains was observed from 1977.5 to 1991.8 despite an apparent increase in seismicity (ML > 4.5) beginning in late 1987 in the northern Los Angeles basin immediately to the south. The observed deformation (0.13±0.01 µstrain/yr right‐lateral shear across a vertical plane striking
Authors
James C. Savage, Michael Lisowski
The volcanic, sedimentologic, and paleolimnologic history of the Crater Lake caldera floor, Oregon:Evidence for small caldera evolution
Apparent phreatic explosion craters, caldera-floor volcanic cones, and geothermal features outline a ring fracture zone along which Mount Mazama collapsed to form the Crater Lake caldera during its climactic eruption about 6,850 yr B.P. Within a few years, subaerial deposits infilled the phreatic craters and then formed a thick wedge (10-20 m) of mass flow deposits shed from caldera walls. Intense
Authors
C. Hans Nelson, Charles R. Bacon, Stephen W. Robinson, David P. Adam, J. Platt Bradbury, John H. Barber, Deborah Schwartz, Ginger Vagenas