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D. W. Peterson

Publications and source records attributed to D. W. Peterson.

17 recordsLinked to original sources
USGS2012

A deep research drill hole at the summit of an active volcano, Kilauea, Hawaii

Drilling and geophysical logging data for a 1,262 m‐deep bore hole in the area inferred to overlie the magma reservoir of Kilauea Volcano, Hawaii, support earlier interpretations based on surface geophysical surveys that a zone of brackish or saline water lies above the reservoir. Temperatures encountered within the hole are not sufficiently high to warrant commercial interest; the maximum temperature, 137°C, is at the hole bottom. However, the temperature gradient toward the bottom of the hole (approximately 160 m below sea level) increases sharply to about 370°C/km, perhaps partly reflecting the effect of decreased water circulation as suggested by the geophysical logging data. If this gradient persists or increases with depth, magmatic temperatures would be attained within 3 km from the hole bottom (i.e., approximately 4 km from ground surface)—a depth in accord with data from ground‐deformation and seismic studies.

Hawaii↗
USGS2012

Volcanic hazards and public response

Although scientific understanding of volcanoes is advancing, eruptions continue to take a substantial toll of life and property. Some of these losses could be reduced by better advance preparation, more effective flow of information between scientists and public officials, and better understanding of volcanic behavior by all segments of the public. The greatest losses generally occur at volcanoes that erupt infrequently where people are not accustomed to dealing with them. Scientists sometimes tend to feel that the blame for poor decisions in emergency management lies chiefly with officials or journalists because of their failure to understand the threat. However, the underlying problem embraces a set of more complex issues comprising three pervasive factors. The first factor is the volcano: signals given by restless volcanoes are often ambiguous and difficult to interpret, especially at long-quiescent volcanoes. The second factor is people: people confront hazardous volcanoes in widely divergent ways, and many have difficulty in dealing with the uncertainties inherent in volcanic unrest. The third factor is the scientists: volcanologists correctly place their highest priority on monitoring and hazard assessment, but they sometimes fail to explain clearly their conclusions to responsible officials and the public, which may lead to inadequate public response. Of all groups in society, volcanologists have the clearest understanding of the hazards and vagaries of volcanic activity; they thereby assume an ethical obligation to convey effectively their knowledge to benefit all of society. If society resists, their obligation nevertheless remains. They must use the same ingenuity and creativity in dealing with information for the public that they use in solving scientific problems. When this falls short, even excellent scientific results may be nullified.

Journal of Geophysical Research Solid Earth↗
USGS2001

Mountain hemlock growth responds to climatic variability at annual and decadal time scales

Improved understanding of tree growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. We used dendroecological methods to study the effects of climatic variability on radial growth of a subalpine conifer, mountain hemlock ( Tsuga mertensiana ). Tree-ring chronologies were developed for 31 sites, spanning the latitudinal and elevational ranges of mountain hemlock in the Pacific Northwest. Factor analysis was used to identify common patterns of interannual growth variability among the chronologies, and correlation and regression analyses were used to identify climatic factors associated with that variability. Factor analysis identified three common growth patterns, representing groups of sites with different climate–growth relationships. At high-elevation and midrange sites in Washington and northern Oregon, growth was negatively correlated with spring snowpack depth, and positively correlated with growth-year summer temperature and the winter Pacific Decadal Oscillation index (PDO). In southern Oregon, growth was negatively correlated with spring snowpack depth and previous summer temperature, and positively correlated with previous summer precipitation. At the low-elevation sites, growth was mostly insensitive to annual climatic variability but displayed sensitivity to decadal variability in the PDO opposite to that found at high-elevation sites. Mountain hemlock growth appears to be limited by late snowmelt, short growing seasons, and cool summer temperatures throughout much of its range in the Pacific Northwest. Earlier snowmelt, higher summer temperatures, and lower summer precipitation in southern Oregon produce conditions under which growth is limited by summer temperature and/or soil water availability. Increasing atmospheric CO 2 concentrations could produce warmer temperatures and reduced snowpack depths in the next century. Such changes would likely increase mountain hemlock growth and productivity throughout much of its range in Washington and northern Oregon. Increased summer drought stress and reduced productivity would be likely, however, in mountain hemlock forests of southern Oregon and near the species lower elevation limit at some sites.

Oregon, Washington↗
USGS1994

Development of lava tubes in the light of observations at Mauna Ulu, Kilauea Volcano, Hawaii

During the 1969-1974 Mauna Ulu eruption on Kilauea's upper east rift zone, lava tubes were observed to develop by four principal processes: (1) flat, rooted crusts grew across streams within confined channels; (2) overflows and spatter accreted to levees to build arched roofs across streams; (3) plates of solidified crust floating downstream coalesced to form a roof; and (4) pahoehoe lobes progressively extended, fed by networks of distributaries beneath a solidified crust. Still another tube-forming process operated when pahoehoe entered the ocean; large waves would abruptly chill a crust across the entire surface of a molten stream crossing through the surf zone. These littoral lava tubes formed abruptly, in contrast to subaerial tubes, which formed gradually. All tube-forming processes were favored by low to moderate volume-rates of flow for sustained periods of time. Tubes thereby became ubiquitous within the pahoehoe flows and distributed a very large proportionof the lava that was produced during this prolonged eruption. Tubes transport lava efficiently. Once formed, the roofs of tubes insulate the active streams within, allowing the lava to retain its fluidity for a longer time than if exposed directly to ambient air temperature. Thus the flows can travel greater distances and spread over wider areas. Even though supply rates during most of 1970-1974 were moderate, ranging from 1 to 5 m3/s, large tube systems conducted lava as far as the coast, 12-13 km distant, where they fed extensive pahoehoe fields on the coastal flats. Some flows entered the sea to build lava deltas and add new land to the island. The largest and most efficient tubes developed during periods of sustained extrusion, when new lava was being supplied at nearly constant rates. Tubes can play a major role in building volcanic edifices with gentle slopes because they can deliver a substantial fraction of lava erupted at low to moderate rates to sites far down the flank of a volcano. We conclude, therefore, that the tendency of active pahoehoe flows to form lava tubes is a significant factor in producing the common shield morphology of basaltic volcanoes.

Bulletin of Volcanology↗
USGS1982

Storage, migration, and eruption of magma at Kilauea volcano, Hawaii, 1971-1972

The magmatic plumbing system of Kilauea Volcano consists of a broad region of magma generation in the upper mantle, a steeply inclined zone through which magma rises to an intravolcano reservoir located about 2 to 6 km beneath the summit of the volcano, and a network of conduits that carry magma from this reservoir to sites of eruption within the caldera and along east and southwest rift zones. The functioning of most parts of this system was illustrated by activity during 1971 and 1972. When a 29-month-long eruption at Mauna Ulu on the east rift zone began to wane in 1971, the summit region of the volcano began to inflate rapidly; apparently, blockage of the feeder conduit to Mauna Ulu diverted a continuing supply of mantle-derived magma to prolonged storage in the summit reservoir. Rapid inflation of the summit area persisted at a nearly constant rate from June 1971 to February 1972, when a conduit to Mauna Ulu was reopened. The cadence of inflation was twice interrupted briefly, first by a 10-hour eruption in Kilauea Caldera on 14 August, and later by an eruption that began in the caldera and migrated 12 km down the southwest rift zone between 24 and 29 September. The 14 August and 24-29 September eruptions added about 107 m3 and 8 ?? 106 m3, respectively, of new lava to the surface of Kilauea. These volumes, combined with the volume increase represented by inflation of the volcanic edifice itself, account for an approximately 6 ?? 106 m3/month rate of growth between June 1971 and January 1972, essentially the same rate at which mantle-derived magma was supplied to Kilauea between 1952 and the end of the Mauna Ulu eruption in 1971. The August and September 1971 lavas are tholeiitic basalts of similar major-element chemical composition. The compositions can be reproduced by mixing various proportions of chemically distinct variants of lava that erupted during the preceding activity at Mauna Ulu. Thus, part of the magma rising from the mantle to feed the Mauna Ulu eruption may have been stored within the summit reservoir from 4 to 20 months before it was erupted in the summit caldera and along the southwest rift zone in August and September. The September 1971 activity was only the fourth eruption on the southwest rift zone during Kilauea's 200 years of recorded history, in contrast to more than 20 eruptions on the east rift zone. Order-of-magnitude differences in topographic and geophysical expression indicate greatly disparate eruption rates for far more than historic time and thus suggest a considerably larger dike swarm within the east rift zone than within the southwest rift zone. Characteristics of the historic eruptions on the southwest rift zone suggest that magma may be fed directly from active lava lakes in Kilauea Caldera or from shallow cupolas at the top of the summit magma reservoir, through fissures that propagate down rift from the caldera itself at the onset of eruption. Moreover, emplacement of this magma into the southwest rift zone may be possible only when compressive stress across the rift is reduced by some unknown critical amount owing either to seaward displacement of the terrane south-southeast of the rift zone or to a deflated condition of Mauna Loa Volcano adjacent to the northwest, or both. The former condition arises when the forceful emplacement of dikes into the east rift zone wedges the south flank of Kilauea seaward. Such controls on the potential for eruption along the southwest rift zone may be related to the topographic and geophysical constrasts between the two rift zones. ?? 1982.

Journal of Volcanology and Geothermal Research↗
USGS1977

Natural hazards on the island of Hawaii

The island of Hawaii and the other islands of the Hawaiian chain are products of volcanic eruptions. Lava flows from hundreds of thousands of eruptions through countless centuries have built the Hawaiian Islands. Some volcanoes on the island of Hawaii have been very active during historic time, and similar activity is expected to continue throughout the foreseeable future.

Hawai'i↗
USGS1976

A deep research drill hole at Kilauea Volcano, Hawaii

A 1262-m-deep bore hole was drilled at the summit of Kilauea Volcano, Hawaii, to test predictions based on surface geophysical surveys and to obtain information on the hydrothermal regime above a postulated magma reservoir. Data from the drilling and geophysical borehole logs tend to confirm earlier predictions that a mound of brackish or saline water is present above the inferred magma body. Temperatures within the hydrothermal system are not sufficiently high to indicate deposits of economic interest, but the gradient toward the bottom of the hole (approximately 160 m below sea level) is high, about 370°C per kilometer. The maximum temperature, 137°C, is at the hole bottom.

Hawaii↗
USGS1973

Flow of lava into the sea, 1969–1971, Kilauea Volcano, Hawaii

Lava from the Mauna Ulu eruption on Kilauea Volcano entered the sea on the south coast of the Island of Hawaii three times from 1969 to 1971. Two of these flows were investigated underwater by divers, one while lava was actively flowing. The June 1969 flow entered the sea as a narrow flow of aa. Below sea level, the flow maintained continuity and flowed at least several hundred meters to a depth beyond 70 m. Several cylindrical flow lobes about 1 m in diameter and about 10 to 15 m long emerged from the side of the aa flow at a depth of about 25m. Underwater investigations, combined with subaerial observations, revealed that the March–May 1971 flow produced a distinct lava delta composed of subaerial pahoehoe lava resting on a submarine sequence of steeply dipping foreset-bedded volcanic sand and rubble that includes conformably dipping cylindrical lava tongues. Most of the pahoehoe streams pouring over the sea cliff are quenched and shattered to glassy sand and rubble that in turn is further fragmented by vigorous wave action and avalanching. In some places, however, larger pahoehoe flows maintain coherence across the cliff and through the surf zone to feed submarine lava tongues. Underwater, these active lava tongues emitted a roaring noise as lava flowed inside their outer black glassy walls. Periodically, cracks exposed the brightly incandescent lava within, and pillow-like buds and toes grew from the top and sides of the lava tongue. Only a small amount of steam was generated underwater. Water temperature close to the active tongues was elevated only 2.5°C.

Hawaii↗
USGS1972

The complex filling of alae crater, Kilauea Volcano, Hawaii

Since February 1969 Alae Crater, a 165-m-deep pit crater on the east rift of Kilauea Volcano, has been completely filled with about 18 million m 3 of lava. The filling was episodic and complex. It involved 13 major periods of addition of lava to the crater, including spectacular lava falls as high as 100 m, and three major periods of draining of lava from the crater. Alae was nearly filled by August 3, 1969, largely drained during a violent ground-cracking event on August 4, 1969, and then filled to the low point on its rim on October 10, 1969. From August 1970 to May 1971, the crater acted as a reservoir for lava that entered through subsurface tubes leading from the vent fissure 150 m away. Another tube system drained the crater and carried lava as far as the sea, 11 km to the south. Much of the lava entered Alae by invading the lava lake beneath its crust and buoying the crust upward. This process, together with the overall complexity of the filling, results in a highly complicated lava lake that would doubtless be misinterpreted if found in the fossil record.

Hawaii↗
USGS1968

Tertiary gold-bearing channel gravel in northern Nevada County, California

The remains of a huge Tertiary gravel-filled channel lie in the area between the South and Middle Yuba Rivers in northern Nevada County, Calif. The deposits in this channel were the site of some of the most productive hydraulic gold mines in California between the 1850's and 1884. The gravel occupies a major channel and parts of several tributaries that in Tertiary time cut into a surface of Paleozoic and Mesozoic igneous and metamorphic rocks. The gravel is partly covered by the remains of an extensive sheet of volcanic rocks, but it crops out along the broad crest of the ridge between the canyons of the South and Middle Yuba Rivers. The lower parts of the gravel deposits generally carry the highest values of placer gold. Traditionally, the richest deposits of all are found in the so-called blue gravel, which, when present, lies just above the bedrock and consists of a very coarse, poorly sorted mixture of cobbles, pebbles, sand, and clay. It is unoxidized, and, at least locally, contains appreciable quantities of secondary sulfide minerals, chiefly pyrite. Information in drill logs from private sources indicates that a 2-mile stretch of the channel near North Columbia contains over half a million ounces of gold dispersed through about 22 million cubic yards of gravel at a grade .averaging about 81 cents per cubic yard. The deposit is buried at depths ranging from 100 to 400 feet. Several geophysical methods have been tested for their feasibility in determining the configuration of the buried bedrock surface, in delineating channel gravel buried under volcanic rocks, and in identifying concentrations of heavy minerals within the gravel. Although the data have not yet been completely processed, preliminary conclusions indicate that some methods may be quite useful. A combination of seismic-refraction and gravity methods was used to determine the depth and configuration of the bottom of the channel to an accuracy within 10 percent as checked by the drill holes. Seismic-refraction methods have identified depressions which are in the bedrock surface, below volcanic rocks, and which may be occupied by gravels. Seismic methods, however, cannot actually recognize the presence of low-velocity gravels beneath the higher velocity volcanic rocks. Electromagnetic methods, supplemented in part by induced-polarization methods, show promise of being able to recognize and trace blue gravel buried less than 200 feet deep. A broad vague magnetic anomaly across the channel suggests that more precise magnetic studies might delineate concentrations of magnetic material. The usefulness of resistivity methods appears from this study to be quite restricted because of irregular topography and the variable conductivity of layers within the gravel.

Circular↗