Volcanic activity and ground deformation hazard analysis for the Hawaii Geothermal Project environmental impact statement
No abstract available
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Geology topics
Richard B. Moore
Publications and source records attributed to Richard B. Moore.
Volcanologic investigations in the Commonwealth of the Northern Mariana Islands, September-October 1990
U.S. Geological Survey volcanologists examined the ten volcanoes in the active Mariana Arc north of Saipan in May 1992, at the request of the Governor and the Disaster Control Office of the Commonwealth of the Northern Mariana Islands (CNMI). A shallow earthquake swarm on Anatahan in March-April 1990 and reports of possible new fuming on Agrigan in August 1990 had prompted the evacuation of all CNMI islands north of Saipan. None of the volcanoes in the chain erupted during our visit. Five uninhabited islands (Farallon de Pajaros, Maug, Asuncion, Guguan, and Sarigan) were inspected only from the air, while the other four were studied in more detail. The previously installed seismic stations on Anatahan, Alamagan, and South Pagan were upgraded. A new station was established at the southwestern base of the intermittently active Mount Pagan, on the northern end of Pagan Island. Portable seismometers were operated on Anatahan, Alamagan, Pagan, and Agrigan. The seismometers on Anatahan, Alamagan, and Agrigan recorded no local shallow earthquake swarms nor volcanic tremor indicative of shallow magmatic movement. On Mount Pagan, intermittent low-amplitude tremor indicated the continuing possibility of occasional small ash eruptions, which prior to our visit had been witnessed in April 1992. Ash eruptions resumed in February 1993. Electronic distance measurement (EDM) lines were remeasured on Agrigan, Mount Pagan, and Anatahan. Line length changes were generally insignificant, in accord with the absence of significant shallow seismicity. Hot spring waters were collected on Agrigan, Pagan, and Anatahan, and fumarole temperatures were measured on Agrigan, Pagan, Alamagan, and Anatahan. The temperature data showed no indication of an impending significant change in the state of these volcanoes. We mapped the geology of Alamagan, collected charcoal to date eruptions of Alamagan and Mount Pagan, and collected rocks on Agrigan, Pagan, Alamagan, and Anatahan for petrographic and chemical studies. We conclude that the low shallow seismicity, lack of significant deformation, and low fumarole temperatures suggest that no eruption is likely soon on Agrigan, Alamagan, or Anatahan. The persistent low-level volcanic tremor on Mount Pagan suggests that intermittent small explosive eruptions may continue to occur.
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Volcanic geology and eruption frequency, São Miguel, Azores
Six volcanic zones comprise São Miguel, the largest island in the Azores. All are Quaternary in age except the last, which is partly Pliocene. From west to east the zones are (1) the trachyte stratovolcano of Sete Cidades, (2) a field of alkali-basalt cinder cones and lava flows with minor trachyte, (3) the trachyte stratovolcano of Agua de Pau, (4) a field of alkali-basalt cinder cones and lava flows with minor trachyte and tristanite, (5) the trachyte stratovolcano of Furnas, and (6) the Nordeste shield, which includes the Povoação caldera and consists of alkali basalt, tristanite, and trachyte. New radiocarbon and K-Ar ages augment stratigraphic data obtained during recent geologic mapping of the entire island and provide improved data to interpret eruption frequency. Average dormant intervals for the past approximately 3000 years in the areas active during that time are about 400 years for Sete Cidades, 145 for zone 2, 1150 for Agua de Pau, and 370 for Furnas. However, the average dormant interval at Sete Cidades increased from 400 to about 680 years before each of the past two eruptions, and the interval at Furnas decreased from 370 to about 195 years before each of the past four eruptions. Eruptions in zone 4 occurred about once every 1000 years during latest Pleistocene and early Holocene time; none has occurred for about 3000 years. The Povoação caldera truncates part of the Nordeste shield and probably formed during the middle to late Pleistocene. Calderas formed during latest Pleistocene time at the three younger stratovolcanoes in the sequence: outer Agua de Pau (between 46 and 26.5 ka), Sete Cidades (about 22 ka), inner Agua de Pau (15.2 ka), and Furnas (about 12 ka). Normal faults are common, but many are buried by Holocene trachyte pumice. Most faults trend northwest or west-northwest and are related to the Terceira rift, whose most active segment on São Miguel passes through Sete Cidades and zone 2. A major normal fault displaces Nordeste lavas 150–250 m and may mark the location of an ancestral Terceira rift. Recent seismicity (e.g., in the 1980s) generally has been scattered, but some small earthquake swarms have occurred beneath the north-eastern flank of Agua de Pau.
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Cosmic ray exposure dating with in situ produced cosmogenic 3He: Results from young Hawaiian lava flows
In an effort to determine the in situ production rate of spallation-produced cosmogenic 3 He, and evaluate its use as a surface exposure chronometer, we have measured cosmogenic helium contents in a suite of Hawaiian radiocarbon-dated lava flows. The lava flows, ranging in age from 600 to 13,000 years, were collected from Hualalai and Mauna Loa volcanoes on the island of Hawaii. Because cosmic ray surface-exposure dating requires the complete absence of erosion or soil cover, these lava flows were selected specifically for this purpose. The 3 He production rate, measured within olivine phenocrysts, was found to vary significantly, ranging from 47 to 150 atoms g −1 yr −1 (normalized to sea level). Although there is considerable scatter in the data, the samples younger than 10,000 years are well-preserved and exposed, and the production rate variations are therefore not related to erosion or soil cover. Data averaged over the past 2000 years indicate a sea-level 3 He production rate of 125 ± 30atoms g −1 yr −1 , which agrees well with previous estimates. The longer record suggests a minimum in sea level normalized 3 He production rate between 2000 and 7000 years (55 ± 15atoms g −1 yr −1 ), as compared to samples younger than 2000 years (125 ± 30 atoms g −1 yr −1 ), and those between 7000 and 10,000 years (127 ± 19atoms g −1 yr −1 ). The minimum in production rate is similar in age to that which would be produced by variations in geomagnetic field strength, as indicated by archeomagnetic data. However, the production rate variations (a factor of 2.3 ± 0.8) are poorly determined due to the large uncertainties in the youngest samples and questions of surface preservation for the older samples. Calculations using the atmospheric production model of O'Brien (1979) [35], and the method of Lal and Peters (1967) [11], predict smaller production rate variations for similar variation in dipole moment (a factor of 1.15–1.65). Because the production rate variations, archeomagnetic data, and theoretical estimates are not well determined at present, the relationship between dipole moment and production rate will require further study. Precise determination of the production rate is an important uncertainty in the surface-exposure technique, but the data demonstrate that it is feasible to date samples as young as 600 years of age providing that there has been no erosion or soil cover. Therefore, the technique will have important applications for volcanology, glacial geology, geomorphology and archaeology.
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Preliminary geologic map of the Puu Anahulu quadrangle, Hawaii
Vent deposits and lava flows from Hualalai Volcano and lava flows from Mauna Loa and Mauna Kea Volcanoes cover the Puu Anahulu 7 1/2-minute quadrangle. Hualalai's diffuse north-trending rift zone, marked by the large trachyte cone of Puu Waawaa and several basaltic spatter cones, is located mainly in the southwestern part of the quadrangle. Several Hualalai flows originated in the Hualalai quadrangle, crossed the Puu Anahulu quadrangle, and terminated in the Kiholo quadrangle. Hualalai flows cover most of the western half of the quadrangle and are interlayered with Mauna Loa lavas along a 2-kilometer-wide strip from southeast to northwest across the middle of the Puu Anahulu quadrangle. Mauna Loa flows cover most of the eastern half. Mauna Kea flows are restricted to the northeastern corner, where they underlie Hualalai and Mauna Loa lavas. A few extensive and relatively young flows from Hualalai and Mauna Loa cover most of the quadrangle; thus, the older units are generally small in area. The oldest units in the quadrangle are the trachyte cone of Puu Waawaa and its flow, which includes Puu Anahulu, covers about 7 percent of the quadrangle. Basaltic lavas of Hualalai range in age from latest Pleistocene to less than 2,000 years. Pleistocene lavas cover about 5 percent of this quadrangle, lavas that are 5,000 - 10,000 years old cover about 5 percent, lavas that are 3,000 - 5,000 years old cover about 3 percent, and three extensive flows that are 1,500 - 3,000 years old cover about 25 percent. The oldest Mauna Loa flows, that are probably 5,000 - 10,000 years old, cover about 2 percent of this quadrangle, flows that are 3,000 - 5,000 years old cover about 18 percent, six extensive flows that are 1,500 - 3,000 years old cover about 23 percent, and the 1859 flow, that is the youngest volcanic unit, and covers about 10 percent of its area. Two hawaiite flows from Mauna Kea, that are late Pleistocene in age, cover about 2 percent of the quadrangle.
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Geologic map of the central part of the San Francisco Volcanic Field, north-central Arizona
The geologic map of the central part of the San Francisco volcanic field (called the Central map area) is one of five adjoining geologic maps (fig. 1) prepared under the Geothermal Research Program of the U.S. Geological Sruvey as a basis for interpreting the history of magmatic activity in the volcanic field. The San Francisco field, which is largely Pliocene and Pleistocene in age, is in northern Arizona, just north of the broad transition zone between the Colorado Plateau. The Central map area encompasses approximately 1,600 km 2 . It spans the middle part of the San Francisco volcanic field and includes some of the oldest and youngest volcanic units in the volcanic field.
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Geologic map of the east part of the San Francisco Volcanic Field, north-central Arizona
The geologic map of the east part of the San Francisco volcanic field (called the East map area) is one of five adjoining geologic maps (fig. 1) prepared under the Geothermal Research Program of the U.S. Geological Survey as a basis for interpreting the history of magmatic activity in the volcanic field. This map is a revision of an earlier one (Moore and Wolfe, 1976). Detail of pyroclastic and alluvial deposits has been reduced for clarity on this uncolored version, and eolian deposits, represented by numerous active dunes of basaltic ash, have been completely omitted. Small cinder cones developed over rootless vents on the basalt flow (Qbb) of = vent 2019 have also been omitted. In addition, a few changes have been made in correlations of flows and vents. The stratigraphic classification has been modified because magnetic-polarity determinations and new K-Ar ages indicate that the physiographically defined Tappan and Woodhouse age groups (Moore and others, 1976) overlap significantly in age, and the rocks of those age groups are now assigned to the Brunhes or Matuyama Polarity Chronozones (Mankinen and Dalrymple, 1979). The San Francisco field, which is largely Pliocene and Pleistocene in age, is in northern Arizona, just north of the broad transition zone between the Colorado Plateau and the Basin and Range province. It is one of several dominantly basaltic volcanic fields of late Cenozoic age situated near the southern margin of the Colorado Plateau. The East map area encompasses approximately 1,220 km 2 . The volcanic field contains rocks ranging in composition from basalt to rhyolite--the products of eruption through Precambrian basement rocks and approximately a kilometer of overlying, nearly horizontal, Paleozoic and Mesozoic sedimentary rocks. About 500 km 3 of erupted rocks cover about 5,000 km 2 of predominantly Permian and locally preserved Triassic sedimentary rocks that form the erosionally stripped surface of the Colorado Plateau in northern Arizona. In the East map area, basalt, basaltic andesite and locally associated small dacite domes, and, in a few cases, andesite were extruded from numerous individual vents, each of which presumably erupted briefly and then became inactive. Such short-lived vents, represented mainly by cinder cones or tuff rings, are widely distributed over the map area, and their flows cover much of its surface. However, repeated eruption of andesite, dacite, and rhyolite domes and flows formed the O'Leary Peak eruptive center in the northwest part of the map area, and flows of andesite (Qa 1 and Qa 2 ) from the San Francisco Mountain stratovolcano entered the East map area from the west. A northeastward progression of volcanism during the past 15 m.y., from central Arizona into the San Francisco volcanic field, is shown by the compilation of Luedke and Smith (1978). Although complicated in detail, a general northeastward to eastward progression of volcanic activity is also apparent within the San Francisco volcanic field. Thus, much of the eruptive activity of the East map area occurred late in the development of the San Francisco field, and the East map area includes the youngest volcanic rocks of the field. These youngest rocks were formed during the Sunset Crater eruption, which occurred within the past 1,000 years (Smiley, 1958). A northeast-trending, faulted monocline occurs near Doney Mountain in the north-central part of the East map area, and a broad north- to northwest-trending anticline occurs at the east edge of the map area. Nearby volcanic rocks are not folded or faulted by either structure. Northwest-trending normal faults of small throw occur in the southern and northwestern parts of the map area. The faults in the northwestern part transect basalt flows of Matuyama and Brunhes ages (Tmb, Qmb, and Qbb). The volcanic rocks are not faulted elsewhere in the East map area. However, local northwestward elongation and alignment of vent deposits, as shown for example by the fissure deposits of the Sunset Crater eruption (Qbsbf), indicate the presence of a northwest-trending fracture system that apparently localized some of the eruptive feeders.
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Preliminary geologic map of Agua de Pau volcano, Sao Miguel, Azores
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Preliminary geologic map of Furnas Volcano, San Miguel, Azores
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Geohydrology of the valley-fill aquifer in the Sprout and Fishkill creeks area, Dutchess County, New York
This report is the fifth in a series of 11 map sets depicting geohydrologic conditions in selected aquifers in upstate New York. Geohydrologic data are compiled on six maps at 1:24,000 scale. Together the maps provide a comprehensive overview of a major valley-fill aquifer in southwestern Dutchess County and a small part of Putnan County. The maps include surficial geology, geologic sections, water-infiltration potential of soil zone, aquifer thickness, water-table elevations and land use. The valley-fill deposits consist of alluvial silt and sand, glacial-outwash (sand and gravel), ice-contact sand and gravel, till, and lacustrine silt and clay. The sand and gravel have relatively high permeabilities whereas the till, silt and clay deposits have relatively low permeabilities. Saturated layers of sand and gravel underlie confining layers of silt and clay, and also underlie confining till. The water-infiltration potential of the soil zone of the valley-fill varies widely. Aquifer thickness data is sparse, especially data on the lower confined aquifer layers. Water-table elevations within the surface aquifer are gently sloping, directing ground-water flow towards streams into which discharge occurs. The use of land overlying the aquifer is predominantly agricultural and residential, with lesser amounts of commercial and industrial uses. (USGS)
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Volcanic rocks of the eastern and northern parts of the San Francisco volcanic field, Arizona
The eastern and northern parts of the San Francisco volcanic field, between San Francisco Mountain and the Little Colorado River, contain about 175 cinder cones, many with one or more associated lava flows, and one center of silicic volcanism, O'Leary Peak. Basaltic flows and cones are divided into five groups, primarily on the bases of stratigraphic and physiographic relations, degree of weathering and erosion, K-Ar and tree-ring age determinations, and, in part, chemical and petrographic data: Basaltic rocks of Sunset age -------- A.D. 1064-1065 Holocene. Basaltic rocks of Merriam age ----- <100,100 years Pleistocene. Basaltic rocks of Tappan age ------- 0.2-0.7 m.y. Do. Basaltic rocks of Woodhouse age --- 0.8-3.0 m.y. Pliocene and Pleistocene. Basalt of Cedar Ranch --------------- 5.5 m.y. Pliocene. The flows and cones are predominantly alkali olivine basalt, commonly nepheline normative, and characterized by a single Ca-rich pyroxene phase and the absence of the olivine-pyroxene reaction relation. By depletion in olivine and pyroxene these basalts grade into alkali-rich high-alumina basalts; the most silicic of which contain both Ca-rich and Ca-poor pyroxene but show no olivine reaction. By relative enrichment in K 2 O and SiO 2 , alkali olivine basalts grade into intersertal basaltic andesites that contain, in addition to olivine, two pyroxene phases and minor primary cristobalite. Volcanic rocks of O'Leary Peak consist largely of rhyodacite domes, flows, and minor pyroclastic deposits. An andesite flow underlies the rhyodacites and andesitic cinders mantle the rhyodacite porphyry dome that forms O'Leary Peak. This dome, 0.23±0.04 m.y. old, is both underlain and overlain by Tappan-age basaltic rocks. Variation diagrams that include data from the dominantly andesitic to rhyolitic San Francisco Mountain as well as from the mapped area show the differentiated and consanguineous character of the lavas, which are chemically intermediate between typical calc-alkalic and alkalic suites. Sr 87 /Sr 86 ratios of 0.7026 to 0.7050 suggest a mantle origin with little contamination by upper crustal material. Ultramafic and mafic xenoliths with cumulus texture may represent crustal intrusions related to the volcanic rocks. Eruption of intermediate to silicic magmas was generally localized in a few centers such as San Francisco Mountain and O'Leary Peak. In the same general time interval, basaltic eruptions dominated in the surrounding areas.
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