The characteristic size of two types of intrusions identified beneath Kilauea's East Rift zone are uniquely estimated by combining time constraints from fractional crystallization and the rates of magma solidification during cooling. Some intrusions were rapidly emplaced as dikes, but stalled before reaching the surface, and cooled and crystallized to feed later fractionated eruptions. More specifically, using the observed time interval between initial emplacement and eruption of fractionated lava, whose degree of fractionation is estimated from petrologic mixing calculations, the extent of solidification or cooling needed to produce this amount of fractionation can be directly inferred. And from the known erupted volumes the spatial extent or size of this fractionated volume can be analytically related to the full size of the source body itself. Two examples yield dike widths of 82 and 68 Other intrusions remain close to the east rift magma transport path and are observed to last for decades or longer as viable magma bodies that may participate in feeding later eruptions. The thickness of semi-permanent reservoirs near the East Rift Zone magma transport path can be estimated by assuming a resupply rate that is sufficiently frequent to restrict cooling to <10 degrees C. It is inferred that both types of intrusions likely began as dike offshoots from the East Rift Zone magma transport path, but the frequently resupplied bodies may have later been converted to sills or laccoliths of heights estimated at 43-62 m. Our modeled intrusions contrast with models of rapidly emplaced thinner dikes feeding shallow intrusions, which are accompanied by intense rift earthquake swarms and are often associated with eruptions.These calculations show that long-term heating of the wallrock of the magma transport paths serves to slow conduit cooling, which may be partly responsible for sustaining long East Rift Zone eruptions. Adjacent to the vertical transport path beneath Kilauea's summit, the combined effects of heating and ever-increasing, magma supply rate may have forced a commensurate enlarging of the conduit, perhaps explaining the occurrence of a temporary burst of deep (5-15 km) long-period earthquake swarms between 1987 and 1992. (C) 2016 Elsevier B.V. All rights reserved.

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Three Kilauea eruptions have produced accessible lava ponds in the pit craters Kilauea Iki (1959). Alae (1963). and Makaopuhi west pit (1965). These have provided a unique laboratory in which to study the cooling and crystallization of basaltic magma. The results of field and laboratory studies conducted at Kilauea place constraints on processes that take place during cooling of shallow magma chambers and of thick basaltic lava flows. Field methods of study include repeated core drilling to determine the thickness of upper crust. collection of gas and measurement of temperature and oxygen fugacity in uncased drill holes. sampling and measurement of viscosity of molten basalt, and periodic measurement of changes in surface altitude and crack configuration. Laboratory studies include measurement of density, chemical composition, and conductivity of drill core, megascopic and microscopic study of crystal and glass content as a function of depth, time, and temperature, and finite-element modeling of the thermal history. Liquidus temperatures of each magma are at or above 1200°C depending on MgO content. Solidus temperatures are all near 980°C. The interface between rigid ‘crust' and fluid ‘melt' occurs at 1070 ± 50°C. The thickness of upper crust in each lake during the first several months increased at a nearly linear rate of 40 cm per unit change in measured in days. Finite-element modeling of the cooling of Alae lava lake has established that cooling is controlled principally by conductive heat transfer. Most measured temperatures there can be computed within 50°C with a model assuming a latent heat of 80 ± 5 cal/gm and a constant diffusivity of .006 cm2/sec and taking into account the heating and vaporization of the measured rainfall of approximately 250 cm/yr. The rainfall considerably hastened post-solidification cooling of the lake. Measured temperatures can be more closely duplicated using a diffusivity based on the measured density and calculated heat content of the lava and on a conductivity that decreases with porosity and increases with temperature. The cooling rate of Makaopuhi and Kilauea Iki may have been increased by convective heat transfer in the melt, as indicated by measured temperature fluctuations and melt differentiation in Makaopuhi. Three kinds of crystal-liquid differentiation are observed in the lava lakes as inferred from chemical analysis of drill core: (1) gravitative settling of olivine phenocrysts, (2) filter-pressing of low-temperature (l030–1070°C) liquids into open fractures, and (3) downward concentration of augite and plagioclase during inferred convective flow. Similar chemical variation observed in Kilauea rift eruptions suggests that these differentiation processes occur on a larger scale within the Kilauea conduits. Some features are unique to each lake. One example is the pattern of vesiculation represented by changes in crust and melt density with depth and by surface altitude changes. Vesiculation is important in determining the density stratification in each lake, and hence the convective history. The distribution of vesicles depends in part on the initial volatile content and on differences in the mode of filling of each lake. These observations made for any single lava lake cannot, therefore, be directly applied to other basaltic lava flows without consideration of evidence for initial gas content and vesiculation history.

We focus on movement of magma beneath Kilauea from the long summit eruption in 1967-1968 through the first historical sustained eruption on the east rift zone (Mauna Ulu 1969-1974), ending with the occurrence of a magnitude 7.2 earthquake beneath Kilauea's eastern south flank. Magma from the Hawai'iian hot spot continuously moves upward to Summit storage and drives seaward spreading of Kilauea's south flank on a 10-12 km deep decollement. Spreading creates dilation in Kilauea's rift zones and provides room to store magma at depths extending to the decollement surface. During the period of study three types of eruptions - normal (short-lived), episodic and sustained - and three types of intrusions - traditional (summit to rift), inflationary and slow - are classified. Rates of sustained eruption are governed by the geometry of the magmatic plumbing. Swarms of earthquakes beneath the south flank signal increased pressure from magma entering Kilauea's adjacent rift zone. Magma supply rates are obtained by combining the volume of magma transferred to sites of eruption or intrusion with the volume opened by seaward spreading over the same increment of time. In our interpretation the varying character of eruptions and intrusions requires a gradual increase in magma supply rate throughout the period augmented by incremental increases in spreading rate. The three types of eruptions result from different combinations of magma supply and spreading rate.

The shallow part of Kilauea's magma system is conceptually well-understood. Long-period and short-period (brittle-failure) earthquake swarms outline a near-vertical magma transport path beneath Kilauea's summit to 20 km depth. A gravity high centered above the magma transport path demonstrates that Kilauea's shallow magma system, established early in the volcano's history, has remained fixed in place. Low seismicity at 4-7 km outlines a storage region from which magma is supplied for eruptions and intrusions. Brittle-failure earthquake swarms shallower than 5 km beneath the rift zones accompany dike emplacement. Sparse earthquakes extend to a decollement at 10-12 km along which the south flank of Kilauea is sliding seaward. This zone below 5 km can sustain aseismic magma transport, consistent with recent tomographic studies. Long-period earthquake clusters deeper than 40 kin occur parallel to and offshore of Kilauea's south coast, defining the deepest seismic response to magma transport from the Hawaiian hot spot. A path connecting the shallow and deep long-period earthquakes is defined by mainshock-aftershock locations of brittle-failure earthquakes unique to Kilauea whose hypocenters are deeper than 25 km with magnitudes from 4.4 to 5.2. Separation of deep and shallow long-period clusters occurs as the shallow plumbing moves with the volcanic edifice, while the deep plumbing is centered over the hotspot. Recent GPS data agrees with the volcano-propagation vector from Kauai to Maui, suggesting that Pacific plate motion, azimuth 293.5 degrees and rate of 7.4 cm/yr, has been constant over Kilauea's lifetime. However, volcano propagation on the island of Hawaii, azimuth 325 degrees, rate 13 cm/yr, requires southwesterly migration of the locus of melting within the broad hotspot. Deep, long-period earthquakes lie west of the extrapolated position of Kilauea backward in time along a plate-motion vector, requiring southwesterly migration of Kilauea's magma source. Assumed ages of 0.4 my for Kilauea and 0.8 my for Mauna Loa are consistent with this model. Younger ages would apply if Kilauea began its growth south of the locus of maximum melting, as is true for Loihi seamount. We conclude that Kilauea is fed from below the eastern end of the zone of deep long-period earthquakes. Magma transport is vertical below 30 km, then sub-horizontal, following the oceanic mantle boundary separating plagioclase- and spinel-peridotite, then near-vertical beneath Kilauea's summit. The migration of the melting region within the hotspot and Kilauea's sampling of different sources within the melting region can explain (1) the long-term geochemical separation of Kilauea from neighboring volcanoes Mauna Loa and Loihi, and (2) the short-term changes in trace-element and isotope signatures within Kilauea. (c) 2005 Elsevier B.V. All rights reserved.

In order to study the origin of the Grande Ronde basalts (GRs) erupted in the climax stage of the Columbia River basalts (CRBs), we carried out high pressure melting experiments on four of the most primitive rock compositions representing the Yakima group of the CRBs. The voluminous GRs (constituting >80 vol% of CRBs) are totally aphyric basaltic andesites. GRs show very narrow and coherent chemical trends both in major and trace elements as well as isotopes. The silica-rich GRs (SiO2 = 52-56 wt%) can be produced by direct partial melting of a MORE like source material (CRB72-31) at similar to 2 Cpa or similar to 70 lan depth. By 30-50% partial melting of the CRB72-31, the entire compositional range of the GRs can be produced in a narrow temperature interval (1300-1350 degrees C) at similar to 2 Cpa. The aluminous clinopyroxene that appears in the above melting range is consistent as the major controlling phase of the GR trends. The partial melts are very similar to the GRs except for Al2O3 and FeO which could be due to the mismatch in the source rock composition. Judging from the variation in REE, involvement of garnet in GR magma genesis can be ruled out. Small amounts of plagioclase (10-30 wt%) may be present in the partial melting residue. Judging from REE patterns and Nd isotopes of the GRs, the source rock should be unfractionated in REE. Based on the melting experiments, a heterogeneous plume model is proposed for the initial stage of the Yellowstone hot spot. Large lithologically distinct blobs of old oceanic crust components were included in the plume head. The GR magmas were produced by partial melting of the oceanic crust components at the bottom of the North American lithosphere. Similar melting processes of basalt/peridotite composite source may be operating in other LIPs (large igneous provinces). The GR type genuine oceanic crust derived melts may be seen where the ambient peridotite remains under subsolidus conditions. Volume and temperature of mantle plumes may have been overestimated, because contributions from the recycled oceanic crust is so large and the current mantle melting models concern only peridotite source. (C) 1998 Elsevier Science B.V. All rights reserved.

The Hawaii bibliographic database has been created to contain all of the literature, from 1779 to the present, pertinent to the volcanological history of the Hawaiian-Emperor volcanic chain. References are entered in a PC- and Macintosh-compatible EndNote Plus bibliographic database with keywords and abstracts or (if no abstract) with annotations as to content. Keywords emphasize location. discipline, process, identification of new chemical data or age determinations. and type of publication. The database is updated approximately three times a year and is available to upload from an ftp site. The bibliography contained 8460 references at the time this paper was submitted for publication. Use of the database greatly enhances the power and completeness of library searches for anyone interested in Hawaiian volcanism.

More than two hundred years of volcano watching in Hawaii is captured in this pictorial history by three contemporary volcano watchers. Volcanoes have been observed and records have been made of their activity since the early Polynesians recognized the Hawaiian Islands as volcanic and incorporated their awareness of volcanic processes into legends and chants. This illustrated summary of eruptions and earthquakes on the island of Hawaii from the time of Captain Cook's voyage in the late eighteenth century to recent, on going events at Kilauea includes early maps, paintings, drawings, and photographs made by volcano watchers. Lucid, thought provoking, and superbly illustrated, this work highlights the accomplishments of both scientists and lay observers: the Reverend Titus Coan, James D. Dana, Sarah Joiner Lyman, Thomas A. Jaggar, Jerry Eaton, and others. The authors describe the conditions under which the early observers worked, the methods available to them, and the insights they gained through observation. The book also traces the development of volcanology in Hawaii and the history of the Hawaiian Volcano Observatory. It concludes by discussing future challenges to coexistence with Hawaii's active volcanoes.

The lavas of the 1955 east rift eruption of Kilauea Volcano have been the object of considerable petrologic interest for two reasons. First, the early 1955 lavas are among the most differentiated ever erupted at Kilauea, and second, the petrographic character and chemical composition of the lava being erupted changed significantly during the eruption. This shift, from more differentiated (MgO=5.0–5.7%) to more magnesian (MgO=6.2–6.8%) lava, has been variously interpreted, as either due to systematic excavation of a zoned, differentiated magma body, or to invasion of the differentiated magma by more primitive magma, followed by rapid mixing and eruption of the resulting hybrid magmas. Petrologic examination of several nearvent spatter samples of the late 1955 lavas shows abundant evidence for magma mixing, including resorbed and/or reversely zoned crystals of olivine, augite and plagioclase. In addition, the compositional ranges of olivine, plagioclase and groundmass sulfide are very large, implying that the assemblages are hybrid. Core compositions of olivine phenocrysts range from Fo85 to Fo77. The most magnesian olivines in these samples must have originally crystallized from a melt containing 8.0–8.5% MgO, which is distinctly more magnesian than the bulk composition of the late 1955 lavas. The majorelement and trace-element data are either permissive or supportive of a hybrid origin for the late 1955 lavas. In particular, the compositional trends of the 1955 lavas on plots of CaO vs MgO, and the virtual invariance of Al2O3 and Sr in these plagioclase-phyric lavas are more easily explained by magma mixing than by fractionation. The pattern of internal disequilibrium/re-equilibration in the late 1955 spatter samples is consistent with reintrusion and mixing having occurred at least twice, during the latter part of the 1955 eruption. Plagioclase zonation preserves possible evidence for additional, earlier reintrusion events. Least-squares modelling the mixing of early 1955 bulk compositions with various summit lavas±olivine pick the 1952 summit lava as most like the primitive component. The results also indicate the primitive component had MgO=7.5–8.0%, corresponding to liquidus temperatures of 1165–1175°C. The absence of Fe-Ti oxide phenocrysts in the late 1955 lavas implies that the cooler component of the hybrid had T>1110°C. Thus the thermal contrast between the two components may have been as much as 55–65°C, sufficient to produce the conspicuous disequilibrium effects visible in the spatter samples.

Comparaison de l'aptitude de trois modeles theoriques (le modele cognitif-attentionnel, la theorie de l'apprentissage social, le modele des habiletes cognitives) a rendre compte des performances academiques et de l'anxiete liee aux examens

GroundwaterVolume 26, Issue 2 p. 228-228 DISCUSSION OF “A Case for State Certification of Water Experts” Editorial by Jay H. Lehr, July-August 1987 issue, v. 25, no. 4, pp. 386–388 Thomas L. Wright, Thomas L. Wright Chairman, Professional Practices Committee, California State Board of Registration for Geologists and Geophysicists, 136 Jordan Avenue, San Anselmo, California 94960Search for more papers by this author Thomas L. Wright, Thomas L. Wright Chairman, Professional Practices Committee, California State Board of Registration for Geologists and Geophysicists, 136 Jordan Avenue, San Anselmo, California 94960Search for more papers by this author First published: March 1988 https://doi.org/10.1111/j.1745-6584.1988.tb00388.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume26, Issue2March 1988Pages 228-228 RelatedInformation

The 75th anniversary of the founding of the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) was celebrated during January 1987. The festivities began on January 9 with the opening in Hilo of a major exhibit at the Wailoa Center on the current work of HVO, its history, and its special relationship to Hawaii Volcanoes National Park. In addition to spectacular photographs of volcanic activity and HVO field work, the exhibit featured continuous showings of underwater footage taken during the recent eruptive activity (December 1986) and a computer monitor that displayed the activity of HVO seismic net in real time. The exhibit, which was coordinated by HVO librarian/photo archivist Taeko Jane Takahashi and which featured the professional work of HVO photographer J . D. Griggs, was well received and will probably form the core of a future traveling exhibit.