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C. Heliker

Publications and source records attributed to C. Heliker.

9 recordsLinked to original sources
USGS2004

Hawaiian volcano observatory summary 103; Part I, seismic data, January to December 2003

The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year and a chronological narrative describing the volcanic events. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that most data for events of M= 1.5 routinely gathered by the Observatory are included. The emphasis in collection of tilt and deformation data has shifted from quarterly measurements at a few water-tube tilt stations ('wet' tilt) to a larger number of continuously recording borehole tiltmeters, repeated measurements at numerous spirit-level tilt stations ('dry' tilt), and surveying of level and trilateration networks. Because of the large quantity of deformation data now gathered and differing schedules of data reduction, the seismic and deformation summaries are published separately. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data dictated an annual publication beginning with Summary 74 for the year 1974. Summary 86 (the introduction of CUSP at HVO) includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes background information on the seismic network and processing to allow use of the data and to provide an understanding of how they were gathered.

Open-File Report↗
USGS2003

Kilauea east rift zone magmatism: An episode 54 perspective

On January 29 30, 1997, prolonged steady-state effusion of lava from Pu'u'O'o was briefly disrupted by shallow extension beneath Napau Crater, 1 4 km uprift of the active Kilauea vent. A 23-h-long eruption ( episode 54 ) ensued from fissures that were overlapping or en echelon with eruptive fissures formed during episode 1 in 1983 and those of earlier rift zone eruptions in 1963 and 1968. Combined geophysical and petrologic data for the 1994 1999 eruptive interval, including episode 54 , reveal a variety of shallow magmatic conditions that persist in association with prolonged rift zone eruption. Near-vent lava samples document a significant range in composition, temperature and crystallinity of pre-eruptive magma. As supported by phenocryst liquid relations and Kilauea mineral thermometers established herein, the rift zone extension that led to episode 54 resulted in mixture of near-cotectic magma with discrete magma bodies cooled to ≤1100°C. Mixing models indicate that magmas isolated beneath Napau Crater since 1963 and 1968 constituted 32 65% of the hybrid mixtures erupted during episode 54 . Geophysical measurements support passive displacement of open-system magma along the active east rift conduit into closed-system rift -reservoirs along a shallow zone of extension. Geophysical and petrologic data for early episode 55 document the gradual flushing of episode 54 related magma during magmatic recharge of the edifice.

Hawaii↗
USGS2002

Hawaiian Volcano Observatory summary 101: Part 1, seismic data, January to December 2001

The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year and a chronological narrative describing the volcanic events. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that all data for events of M>1.5 routinely gathered by the Observatory are included. The emphasis in collection of tilt and deformation data has shifted from quarterly measurements at a few water-tube tilt stations ("wet" tilt) to a larger number of continuously recording borehole tiltmeters, repeated measurements at numerous spirit-level tilt stations ("dry" tilt), and surveying of level and trilateration networks. Because of the large quantity of deformation data now gathered and differing schedules of data reduction, the seismic and deformation summaries are published separately. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data dictated an annual publication beginning with Summary 74 for the year 1974. Summary 86 (the introduction of CUSP at HVO) includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes enough background information on the seismic network and processing to allow use of the data and to provide an understanding of how they were gathered.

Hawai'i↗
USGS1995

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. Additional rock types include quartz diorite, hornfelsic basalt, dacite, andesite and vein quartz. Disaggregated inclusions are common and define shear planes within the dome. These fragmented inclusions may significantly contaminate analyses of the dacite. The gabbroic inclusions are of four distinct types, all with mineral assemblages consistent with crystallization pressures of less than 9 kb. Textures and major-element compositions indicate that most of the gabbroic inclusions are cumulates. The most abundant inclusion type is laminated gabbronorite, which contains up to 9% interstitial glass, derived from partial melting. The presence of quartz veins and hornblende-bearing veins within sheared zones in the laminated gabbronorite indicates that the source of these inclusions was holocrystalline rock that had been penetrated by water-rich fluids. The gabbronorite contained sufficient water to be susceptible to partial melting when the magma that fed the 1980–1986 eruption sequence was emplaced nearby. Various types of gabbroic inclusions, including the laminated gabbronorite, are common in Mount St. Helens lavas of approximately the last 3000 years. This coincides with the interval in which Mount St. Helens first erupted basalt and basaltic andesite lavas. These observations, together with the fact that the gabbroic inclusions are compositionally unlike any of the Tertiary intrusive rocks in the Mount St. Helens area, strongly suggest that the inclusions are related to the introduction of basalt to the Mount St. Helens magmatic system. The source of the gabbros could be a layered mafic pluton formed through crystal accumulation from multiple batches of basaltic magma emplaced at mid-to upper-crustal depths beneath the volcano. The prevalence of explosive eruptions at Mount St. Helens may play a part in bringing the inclusions to the surface. The eruptive products of the cataclysmic eruption of May 18,1980 contain notably fewer inclusions than the pyroclastic flows and dome lavas erupted subsequently. This suggests that the May 18 eruption shattered conduit wall rock that was subsequently stoped into the magma and carried to the surface later in the eruption series.

Washington↗
USGS1993

Development of the 1990 Kalapana Flow Field, Kilauea Volcano, Hawaii

The 1990 Kalapana flow field is a complex patchwork of tube-fed pahoehoe flows erupted from the Kupaianaha vent at a low effusion rate (approximately 3.5 m3/s). These flows accumulated over an 11-month period on the coastal plain of Kilauea Volcano, where the pre-eruption slope angle was less than 2??. the composite field thickened by the addition of new flows to its surface, as well as by inflation of these flows and flows emplaced earlier. Two major flow types were identified during the development of the flow field: large primary flows and smaller breakouts that extruded from inflated primary flows. Primary flows advanced more quickly and covered new land at a much higher rate than breakouts. The cumulative area covered by breakouts exceeded that of primary flows, although breakouts frequently covered areas already buried by recent flows. Lava tubes established within primary flows were longer-lived than those formed within breakouts and were often reoccupied by lava after a brief hiatus in supply; tubes within breakouts were never reoccupied once the supply was interrupted. During intervals of steady supply from the vent, the daily areal coverage by lava in Kalapana was constant, whereas the forward advance of the flows was sporadic. This implies that planimetric area, rather than flow length, provides the best indicator of effusion rate for pahoehoe flow fields that form on lowangle slopes. ?? 1993 Springer-Verlag.

Bulletin of Volcanology↗
USGS1992

The ten-year eruption of Kilauea Volcano

The Pu'u 'O' o-Kupaianaha eruption now ranks as the longest-lived historic eruption on the East Rift Zone and the most destructive in Kilauea's recent history. About 1 km 3 of lava erupted during the first 0 years of the eruption. Lava flows have destroyed 181 houses and severed the coastal highway along the volcano's south flank, severely restricting transportation on this part of the island of Hawaii. the eruption consisted of many distinct episodes characterized by activity at different vents and by different eruptive styles. the following summarizes the first 10 years of the eruption, starting with the initial outbreak in 1983.

Hawaii↗