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Research about Hawaii

Source-linked reports with geographic coverage including Hawaii.

At least 937 records · Page 52Linked to original sources
USGS1995

Evaluation of ground-water resources From available data, 1992, East Molokai Volcano, Hawaii

Available ground-water data for East Molokai Volcano consist of well-construction information and records of ground-water pumpage, water levels, and chloride concentrations. Ground-water pumpage records are available for ten wells. Seventeen long-term (10 years or more) records of water-level and/or chloride concentration are available for eleven wells; however, only seven of these records are for observation wells. None of the available data show significant long-term changes in water level or chloride concentration; however, short-term changes due to variations in the quantity of water pumped, and rainfall are evident. Evaluation of the historical distribution and rates of ground-water pumpage, and variations in water levels and chloride concentrations is constrained by the scanty distribution of spatial and temporal data. Data show a range in water levels from greater than 850 feet above mean sea level in wells located in the windward valley of Waikolu to about 10 feet in wells located east of Kualapuu to 1 to 5 feet in the wells located along the south shore of East Molokai Volcano. An accurate contour map of water levels and chloride concentrations at the surface of the basal-water body cannot be constructed for any time period. Because water-level and chloride data are not collected at regular time intervals, many long-term records are incomplete. Information on the variation in chloride concentration with depth through the freshwater part of the basal-water body and into the zone of transition between freshwater and saltwater does not exist.

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USGS1994

Relaxation of the south flank after the 7.2-magnitude Kalapana earthquake, Kilauea Volcano, Hawaii

An M = 7.2 earthquake on 29 November 1975 caused the south flank of Kilauea Volcano, Hawaii, to move seaward several meters: a catastrophic release of compression of the south flank caused by earlier injections of magma into the adjacent segment of a rift zone. The focal mechanisms of the mainshock, the largest foreshock, and the largest aftershock suggest seaward movement of the upper block. The rate of aftershocks decreased in a familiar hyperbolic decay, reaching the pre-1975 rate of seismicity by the mid-1980s. Repeated rift-zone intrusions and eruptions after 1975, which occurred within 25 km of the summit area, compressed the adjacent portion of the south flank, apparently masking continued seaward displacement of the south flank. This is evident along a trilateration line that continued to extend, suggesting seaward displacement, immediately after the M = 7.2 earthquake, but then was compressed during a series of intrusions and eruptions that began in September 1977. Farther to the east, trilateration measurements show that the portion of the south flank above the aftershock zone, but beyond the area of compression caused by the rift-zone intrusions and eruptions, continued to move seaward at a decreasing rate until the mid-1980s, mimicking the decay in aftershock rate. Along the same portion of the south flank, the pattern of vertical surface displacements can be explained by continued seaward movement of the south flank and development of two eruptive fissures along the east rift zone, each of which extended from a depth of ∼3 km to the surface. The aftershock rate and continued seaward movement of the south flank are reminiscent of crustal response to other large earthquakes, such as the 1966 M = 6 Parkfield earthquake and the 1983 M = 6.5 Coalinga earthquake.

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USGS1994

Thorium-230 ages of corals and duration of the last interglacial sea-level high stand on Oahu, Hawaii

Thorium-230 ages of emergent marine deposits on Oahu, Hawaii, have a uniform distribution of ages from ∼114,000 to ∼131,000 years, indicating a duration for the last interglacial sea-level high stand of ∼17,000 years, in contrast to a duration of ∼8000 years inferred from the orbitally tuned marine oxygen isotope record. Sea level on Oahu rose to ≥1 to 2 meters higher than present by 131,000 years ago or ∼6000 years earlier than inferred from the marine record. Although the latter record suggests a shift back to glacial conditions beginning at ∼119,000 years ago, the Oahu coral ages indicate a near present sea level until ∼114,000 years ago.

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USGS1994

Chaotic deposition by a giant wave, Molokai, Hawaii

A coral-basalt breccia-conglomerate is exposed >60m above present sea level and nearly 2km inland from the present shoreline on the southwest side of East Molokai Volcano. This deposits was apparently laid down by a giant wave that broke over an outer reef, similar to the present fringing reef, and advanced as a turbulent bore over the back-reef flat, picking up a slurry of carbonate-rich debris and depositing it on the slopes inland as the wave advanced. U-series dating of coral fragments indicates that the age of this deposit is 240-200 ka. This giant wave was most likley caused by one of the many large submarine landslides that have been identified on the lower slopes of the major Hawaiian Islands.

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USGS1994

Volcanic gas emissions and their impact on ambient air character at Kilauea Volcano, Hawaii

Currently, gas emissions from Kilauea occur from the summit caldera, along the middle East Rift Zone (ERZ), and where lava enters the ocean. We estimate that the current ERZ eruption of Kilauea releases between 400 metric tonnes of SO2 per day, during eruptive pauses, to as much as 1850 metric tonnes per day during actively erupting periods, along with lesser amounts of other chemically and radiatively active species including H2S, HCl, and HF. In order to characterize gas emissions from Kilauea in a meaningful way for assessing environmental impact we made a series of replicate grab-sample measurements of ambient air and precipitation at the summit of Kilauea, along its ERZ, and at coastal sites where lava enters the ocean. The grab-sampling data combined with SO2 emission rates, and continuous air quality and meteorological monitoring at the summit of Kilauea show that the effects of these emissions on ambient air character are a complex function of chemical reactivity, source geometry and effusivity, and local meteorology. For all the measurement sites, ambient concentrations of the emitted gases decrease rapidly, even at short distances from point sources. Prevailing tradewinds typically carry the gases and aerosols released to the southwest, where they are further distributed by the regional wind regime. Episodes of kona, or low speed variable winds sometimes disrupt this pattern, however, and allow the gases and their oxidation products to collect at the summit and eastern side of the island. Summit solfatara areas of Kilauea are distinguished by moderate to high ambient SO2, high H2S at one location, and low H2S at all others, and negligible HC1 concentrations, as measured 1 m from degassing point-sources. Summit solfatara rain water has high sulfate and low chloride ioa concentrations, and low pH. The middle ERZ degassing areas show moderate to high SO2 at 100 m away from degassing lava, and low H2S concentrations. Moderate HC1 was found in ambient air. Rain water near the middle ERZ degassing areas have high sulfate, high chloride and low pH. Coastal entry areas are characterized by high HC1 in the gas plume and significant rain-out of this HCl as indicated by low rain water pH, and high rain water chloride. Sulfate in the coastal-entry rainwater is also high. Ambient SO2 and 112S are moderate to high near the coastal entry locations. Ambient air in the lower ERZ thermal and non-thermal areas shows essentially no influence from the on-going eruption, as evidenced by the absence of SO2, H2S, HC1, and the moderate rain water pH with low sulfate concentration. When the current eruption ceases, ERZ and summit gas emissions will be greatly reduced.

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USGS1994

Stability of submerged slopes on the flanks of the Hawaiian Islands, a simplified approach

Undersea transmission lines and shoreline AC-DC conversion stations and near-shore transmission lines are being considered as part of a system for transporting energy between the Hawaiian Islands. These facilities will need to be designed so that they will not be damaged or destroyed by coastal or undersea landslides. Advanced site surveys and engineering design of these facilities will require detailed site specific analyses, including sediment sampling and laboratory testing of samples, in situ testing of sediment and rock, detailed charting of bathymetry, and two- or three-dimensional numerical analyses of the factors of safety of the slopes against failure from the various possible loading mechanisms. An intermediate approximate approach can be followed that involves gravity and piston cores, laboratory testing and the application of simplified models to determine a seismic angle of repose for actual sediment in the vicinity of the planned facility. An even simpler and more approximate approach involves predictions of angles of repose using classification of the sediment along a proposed route as either a coarse volcaniclastic sand, a calcareous ooze, or a muddy terrigenous sediment. The steepest slope that such a sediment can maintain is the static angle of repose. Sediment may be found on slopes as steep as these, but it must be considered metastable and liable to fail in the event of any disturbance, storm or earthquake. The seismic angle of repose likely governs most slopes on the Hawaiian Ridge. This declivity corresponds to the response of the slope to a continuing seismic environment. As a long history of earthquakes affects the slopes, they gradually flatten to this level. Slopes that exceed or roughly equal this value can be considered at risk to fail during future earthquakes. Seismic and static angles of repose for three sediment types are tabulated in this report.

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USGS1994

Water resources data, Hawaii and other Pacific areas, water year 1993: Volume 1. Hawaii

Water resources data for the 1993 water year for Hawaii and other Pacific Areas consist of records of stage, discharge, and water quality of streams and springs; and water levels and quality of water in wells. This report, volume 1, contains discharge records for 88 gaging stations; water quality for 16 gaging stations, 19 partial-record flow stations, and 142 wells; and water levels for 63 observation wells. Also included are - 107 crest-stage partial record stations, 4 miscellaneous partial-record stations, 6 low-flow partial-record stations, and 45 rainfall stations. These data represent that part of the National Water Data System operated by theU.S. Geological Survey and cooperating State, Federal, and other agencies in Hawaii.

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USGS1993

Anatomy of a basaltic volcano

Kilauea volcano, in Hawaii, may be the best understood basaltic volcano in the world. Magma rises from a depth of 80 km or more and resides temporarily in near-surface reservoirs: eruption begins when the crust above one of these reservoirs splits open in response to a pressure increase. Repeated rift-zone eruptions compress Kilauea's flanks; after decades of accumulation, the stress is relieved in catastrophic earthquakes and southward displacement of the volcano's south flank.

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USGS1993

Water resources data, Hawaii and other Pacific areas, water year 1992: Volume 1. Hawaii

Water resources data for the 1992 water year for Hawaii and other Pacific Areas consist of records of stage, discharge, and water quality of streams and springs; and water levels and water quality in wells. This report, volume 1, contains discharge records for 87 gaging stations; water quality for 16 gaging stations, 20 partial-record flow stations, and 126 wells; and water levels for 63 observation wells. Also included are - 107 crest-stage partial record stations, 4 miscellaneous partial-record stations, and 6 low-flow partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, Federal, and other agencies in Hawaii.

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USGS1993

Changing nest placement of Hawaiian Common Amakihi during the breeding cycle

We studied the nesting behavior of the Common Amakihi ( Hemignathus virens ) from 1970-1981 on the island of Hawaii to determine if the species alters nest placement over a protracted 9-month breeding season. Birds preferentially chose the southwest quadrant of trees in which to build nests during all phases of the breeding season. It appeared that ambient temperature (Ta) was a contributing factor to differential nest placement between early and late phases of the annual breeding cycle. When Ta is low during the early (December-March) breeding period, Common Amakihi selected exposed nesting locations that benefitted them with maximum solar insolation. However, in the later phase of the breeding period (April-July) when Ta was much higher, renesting birds selected nest sites deeper in the canopy in significantly taller trees. This is one of the few documented examples in which a species changes location of nest during a breeding season, thus allowing exploitation of temporally differing microclimatic conditions.

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USGS1993

Where lava meets the sea; Kilauea Volcano, Hawaii

Active volcanoes on the island of Hawai'i provide scientists with exceptional opportunities to observe volcanic phenomena at close range. Such an opportunity occurred on November 24, 1992, when geologists from the Hawaiian Volcano Observatory (HVO) witnessed spectacular explosive interactions between lava and seawater on the southeast coast of the island. As seawater invaded submarine conduits transporting milten lava, large steam explosions produced glowing fountains of lava that rose as high as 100m into the air and built a 7.5-m-high mound of volcanic ejecta called a littoral cone (see cover paragraphs). Seaside explosions of the type and magnitude of the event on November 24, 1992, are infrequent. the observation of this event represents a rare opportunity to enhance our understanding of the birth of littoral cones and the nature of explosive activity when lava enters the ocean.

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