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Research about Hawaii

Source-linked reports with geographic coverage including Hawaii.

At least 775 records · Page 43Linked to original sources
USGS2005

Three-dimensional variable-density flow simulation of a coastal aquifer in southern Oahu, Hawaii, USA

Three-dimensional modeling of groundwater flow and solute transport in the Pearl Harbor aquifer, southern Oahu, Hawaii, shows that the readjustment of the freshwater–saltwater transition zone takes a long time following changes in pumping, irrigation, or recharge in the aquifer system. It takes about 50 years for the transition zone to move 90% of the distance to its new steady position. Further, the Ghyben–Herzberg estimate of the freshwater/saltwater interface depth occurred between the 10 and 50% simulated seawater concentration contours in a complex manner during 100 years of the pumping history of the aquifer. Thus, it is not a good predictor of the depth of potable water. Pre-development recharge was used to simulate the 1880 freshwater-lens configuration. Historical pumpage and recharge distributions were used and the resulting freshwater-lens size and position were simulated through 1980. Simulations show that the transition zone moved upward and landward during the period simulated. Previous groundwater flow models for Oahu have been limited to areal models that simulate a sharp interface between freshwater and saltwater or solute-transport models that simulate a vertical aquifer section. The present model is based on the US Geological Survey’s three-dimensional solute transport (3D SUTRA) computer code. Using several new tools for pre- and post-processing of model input and results have allowed easy model construction and unprecedented visualization of the freshwater lens and underlying transition zone in Hawaii’s most developed aquifer.

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USGS2005

Physical and chemical properties of submarine basaltic rocks from the submarine flanks of the Hawaiian Islands

To evaluate physical and chemical diversity in submarine basaltic rocks, approximately 280 deep submarine samples recovered by submersibles from the underwater flanks of the Hawaiian Islands were analyzed and compared. Based on observations from the submersibles and hand specimens, these samples were classified into three main occurrence types (lavas, coarse-grained volcaniclastic rocks, and fine-grained sediments), each with several subtypes. The whole-rock sulfur content and porosity in submarine basaltic rocks, recovered from depths greater than 2000 m, range from < 10 ppm and 2 vol.% to 2200 ppm and 47 vol.%, respectively. These wide variations cannot be due just to different ambient pressures at the collection depths, as inferred previously for submarine erupted lavas. The physical and chemical properties of the recovered samples, especially a combination of three whole-rock parameters ( F e-oxidation state, S ulfur content, and P orosity), are closely related to the occurrence type. The FSP triangular diagram is a valuable indicator of the source location of basaltic fragments deposited in deep submarine areas. This diagram can be applied to basaltic rocks such as clasts in debris-flow deposits, submarine-emplaced lava flows that may have crossed the shoreline, and slightly altered geological samples.

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USGS2005

Source process of a long-period event at Kilauea volcano, Hawaii

We analyse a long-period (LP) event observed by a dense seismic network temporarily operated at Kilauea volcano, Hawaii, in 1996. We systematically perform spectral analyses, waveform inversions and forward modeling of the LP event to quantify its source process. Spectral analyses identify two dominant spectral frequencies at 0.6 and 1.3 Hz with associated Q values in the range 10-20. Results from waveform inversions assuming six moment-tensor and three single-force components point to the resonance of a horizontal crack located at a depth of approximately 150 m near the northeastern rim of the Halemaumau pit crater. Waveform simulations based on a fluid-filled crack model suggest that the observed frequencies and Q values can be explained by a crack filled with a hydrothermal fluid in the form of either bubbly water or steam. The shallow hydrothermal crack located directly above the magma conduit may have been heated by volcanic gases leaking from the conduit. The enhanced flux of heat raised the overall pressure of the hydrothermal fluid in the crack and induced a rapid discharge of fluid from the crack, which triggered the acoustic vibrations of the resonator generating the LP waveform. The present study provides further support to the idea that LP events originate in the resonance of a crack. 2005 RAS.

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USGS2005

Rediscovery and uncertain future of high-elevation Haleakala carabid beetles (Coleoptera)

Recent biotic surveys in subalpine shrubland on Haleakalā Volcano, Maui, Hawai'i, have resulted in rediscovery of several species of carabid beetles previously known only from their nineteenth-century type specimens. Blackburnia lenta (Sharp), described from specimens collected just below Haleakalā summit in 1894, was found at lower elevational sites ranging from 2,400 to 2,750 m. Mecyclothorax rusticus Sharp, last seen in 1896, and M. nubicola (Blackburn), collected only in 1878, were also rediscovered in that vicinity. Recent collections of B. lenta contradict the U.S. Fish and Wildlife Service's previous classification of this species as one likely to be extinct. Nevertheless, B. lenta's known distribution comprises only 145 ha within an elevational zone that is bounded above and below by unicolonial populations of the invasive alien Argentine ant, Linepithema humile (Mayr). The known recent collections of M. rusticus and M. nubicola also occurred outside the distributional range of the Argentine ant. Mature eggs held in the lateral oviducts of B. lenta females averaged 1.4x the volume of the largest eggs previously reported among 13 species of Blackburnia. We hypothesize that the giant eggs of B. lenta result from selective forces favoring large, well-nourished developing and hatched first-instar larvae, consistent with a patchy distribution of suitable microhabitat and prey in the subalpine Haleakalā landscape. The specialized life history of B. lenta, and coincidence of distributional limits of the three rediscovered carabid species with range limits of the Argentine ant populations suggest that all would be jeopardized by future distributional expansion of Argentine ant. These intersecting phenomena compel us to conclude that B. lenta, M. nubicola, and M. nubicola are appropriate candidates for I.U.C.N. threatened species designation, pending further studies of their geographic ranges and historical trends in abundance.

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USGS2005

Breeding ecology of the Puaiohi (Myadestes palmeri)

We studied the breeding ecology of the critically endangered Puaiohi ( Myadestes palmeri ), a poorly known Hawaiian thrush endemic to the island of Kauai. From 1996 through 1998, we monitored 96 active nests over the course of three breeding seasons. Mean clutch size was 2.0, and pairs produced an average of 1.5 fledglings/successful nest. Pairs renested after failure and some raised multiple broods. The mean annual reproductive effort was 2.1 nesting attempts/territory, and pairs produced a mean 1.1 fledglings/attempt. Large differences in nesting effort and productivity occurred among years, with mean number of fledglings/territory ranging from 0.4 to 4.9. Predation by owls (probably Short-eared Owls, Asio flammeus ) and introduced rats (probably black rats, Rattus rattus ) accounted for most nest failures. The presence of non-breeding floaters in the population and their largely unsuccessful attempts to gain territories in the study area suggest that the population is near carrying capacity. The high reproductive potential of the Puaiohi may help explain its persistence despite the species' historical rarity.

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USGS2005

Reconnaissance gas measurements on the East Rift Zone of Kilauea Volcano, Hawai'i by Fourier transform infrared spectroscopy

We report the results of a set of measurements of volcanic gases on two small ground level plumes in the vicinity of Pu`u `O`o cone on the middle East Rift Zone (ERZ) of Kilauea volcano, Hawai`i on 15 June 2001 using open-path Fourier transform infrared (FTIR) spectroscopy. The work was carried out as a reconnaissance survey to assess the monitoring and research value of FTIR measurements at this volcano. Despite representing emissions of residual volatiles from lava that has undergone prior degassing, the plumes contained detectable amounts of CO2, CO, SO2, HCl, HF and SiF4. Various processes, including subsurface cooling, condensation of water in the atmospheric plume, oxidation, dissolution in water, and reactions with wall rocks at plume vents affect the abundance of these gases. Low concentrations of volcanic CO2 measured against a high ambient background are not well constrained by FTIR spectroscopy. Although there appear to be some differences between these gases and Pu`u `O`o source gases, ratios of HCl/SO2, HF/SO2 and CO/SO2 determined by FTIR measurements of these two small plumes compare reasonably well with earlier published analyses of ERZ vent samples. The measurements yielded emission rate estimates of 4, 11 and 4 t d-1

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USGS2005

Coastal circulation and sediment dynamics along west Maui, Hawaii. Part IV: Measurements of waves, currents, temperature, salinity and turbidity in Honolua Bay, northwest Maui: 2003-2004

High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Honolua Bay, northwest Maui, Hawaii, during 2003 and 2004 to better understand coastal dynamics in coral reef habitats. Measurements were acquired through two different collection methods. Two hydrographic survey cruises were conducted to acquire spatially-extensive, but temporally-limited, three-dimensional measurements of currents, temperature, salinity and turbidity in the winter and summer of 2003. From mid 2003 through early 2004, a bottom-mounted instrument package was deployed in a water depth of 10 m to collect long-term, single-point high-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity. The purpose of these measurements was to collect hydrographic data to learn how waves, currents and water column properties such as water temperature, salinity and turbidity vary spatially and temporally in a near-shore coral reef system adjacent to a major stream drainage. These measurements support the ongoing process studies being conducted as part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program's Coral Reef Project; the ultimate goal is to better understand the transport mechanisms of sediment, larvae, pollutants and other particles in coral reef settings. This report, the final part in a series, describes data acquisition, processing and analysis. Previous reports provided data and results on: Long-term measurements of currents, temperature, salinity and turbidity off Kahana (PART I), the spatial structure of currents, temperature, salinity and suspended sediment along West Maui (PART II), and flow and coral larvae and sediment dynamics during the 2003 summer spawning season (PART III).

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USGS2005

Coastal change rates and patterns: Kaloko-Honokohau National Historical Park, Hawai'i

A collaborative project between the U.S. Geological Survey's Coastal and Marine Geology Program and the National Park Service (NPS) has been developed to create an inventory of geologic resources for National Park Service lands on the Big Island of Hawai'i. The NPS Geologic Resources Inventories are recognized as essential for the effective management, interpretation, and understanding of vital park resources. In general, there are three principal components of the inventories: geologic bibliographies, digital geologic maps, and geologic reports. The geologic reports are specific to each individual park and include information on the geologic features and processes that are important to the management of park resources, including ecological, cultural and recreational resources. This report summarizes a component of the geologic inventory concerned specifically with characterizing the coastal geomorphology of the beach system within Kaloko-Honokohau National Historical Park (NHP) and describes an analysis that utilizes georeferenced and orthorectified aerial photography to understand the spatial and temporal trends in shoreline change from 1950 to 2002. In addition, spatial patterns of beach change were examined and a beach stability map was developed. Both the shoreline change rates and the beach stability map are designed to help Park personnel effectively manage the valuable park resources within the context of understanding natural changes to the KAHO beach system.

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USGS2005

Summary and preliminary interpretations of USGS cruise A-2-02-HW: Underwater video surveys collected off of Oahu, Molokai, and Maui, Hawaii, June-July 2002

The insular shelves of the southern coasts of the islands of Oahu and Molokai, and the western coast of Maui in the Hawaiian Archipelago were surveyed using ship-towed video between June 26 and July 11, 2002, as part of USGS-CMG cruise A-2-02-HW (Figure 1.1). The goals of the survey were to collect underwater video of the sea floor to: (1) Characterize substrate type and benthic habitat distribution; and (2) Ground-truth recently-acquired data including bathymetric (SHOALS) lidar, side-scan sonar, seismic reflection, and surface texture and grain size. The underwater video also aids in the interpretation and evaluation of Hawaii's benthic habitat maps produced by NOAA and coral reef distribution monitored by the State of Hawaii (Coral Reef Assessment and Monitoring Program - CRAMP; http://cramp.wcc.hawaii.edu/ ). Additional metadata for this cruise is available at: http://walrus.wr.usgs.gov/infobank/a/a202hw/html/a-2-02-hw.meta.html

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USGS2005

Hawaiian Volcano Observatory seismic data, January to December 2004

The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year. 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 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. Beginning with 2004, summaries will simply be identified by the year, rather than Summary number. 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.

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USGS2005

Visitor and community survey results for Kilauea Point National Wildlife Refuge and Lighthouse: Completion report

The U.S. Fish and Wildlife Service (USFWS) and the Central Federal Lands Highway Division of the Federal Highway Administration, U.S. Department of Transportation are currently pursuing the planning and potential design of an alternative transportation system (ATS) for Kilauea Point National Wildlife Refuge (Refuge or Kilauea Point NWR). The USFWS and CFLHD seek an alternative transportation solution that provides the highest quality visitor experience and is sensitive to biological and cultural resources and the needs of the local community. In planning the alternative transportation system, managers need to consider how an ATS would change factors such as visitor access, visitor experience, visitor willingness to pay, and visitor net economic benefits. The Policy Analysis and Science Assistance branch (PASA) at the U.S. Geological Survey Fort Collins Science Center is dedicated to studying relations between humans and the environment. The objective of PASA is to conduct studies to understand how humans are affected by environmental management decisions and how human activities impact use and conservation of natural resources.

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USGS2005

Median and low-flow characteristics for streams under natural and diverted conditions, northeast Maui, Hawaii

Flow-duration statistics under natural (undiverted) and diverted flow conditions were estimated for gaged and ungaged sites on 21 streams in northeast Maui, Hawaii. The estimates were made using the optimal combination of continuous-record gaging-station data, low-flow measurements, and values determined from regression equations developed as part of this study. Estimated 50- and 95-percent flow duration statistics for streams are presented and the analyses done to develop and evaluate the methods used in estimating the statistics are described. Estimated streamflow statistics are presented for sites where various amounts of streamflow data are available as well as for locations where no data are available. Daily mean flows were used to determine flow-duration statistics for continuous-record stream-gaging stations in the study area following U.S. Geological Survey established standard methods. Duration discharges of 50- and 95-percent were determined from total flow and base flow for each continuous-record station. The index-station method was used to adjust all of the streamflow records to a common, long-term period. The gaging station on West Wailuaiki Stream (16518000) was chosen as the index station because of its record length (1914-2003) and favorable geographic location. Adjustments based on the index-station method resulted in decreases to the 50-percent duration total flow, 50-percent duration base flow, 95-percent duration total flow, and 95-percent duration base flow computed on the basis of short-term records that averaged 7, 3, 4, and 1 percent, respectively. For the drainage basin of each continuous-record gaged site and selected ungaged sites, morphometric, geologic, soil, and rainfall characteristics were quantified using Geographic Information System techniques. Regression equations relating the non-diverted streamflow statistics to basin characteristics of the gaged basins were developed using ordinary-least-squares regression analyses. Rainfall rate, maximum basin elevation, and the elongation ratio of the basin were the basin characteristics used in the final regression equations for 50-percent duration total flow and base flow. Rainfall rate and maximum basin elevation were used in the final regression equations for the 95-percent duration total flow and base flow. The relative errors between observed and estimated flows ranged from 10 to 20 percent for the 50-percent duration total flow and base flow, and from 29 to 56 percent for the 95-percent duration total flow and base flow. The regression equations developed for this study were used to determine the 50-percent duration total flow, 50-percent duration base flow, 95-percent duration total flow, and 95-percent duration base flow at selected ungaged diverted and undiverted sites. Estimated streamflow, prediction intervals, and standard errors were determined for 48 ungaged sites in the study area and for three gaged sites west of the study area. Relative errors were determined for sites where measured values of 95-percent duration discharge of total flow were available. East of Keanae Valley, the 95-percent duration discharge equation generally underestimated flow, and within and west of Keanae Valley, the equation generally overestimated flow. Reduction in 50- and 95-percent flow-duration values in stream reaches affected by diversions throughout the study area average 58 to 60 percent.

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USGS2004

Application of near real-time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii

Radial Semblance is applied to broadband seismic network data to provide source locations of Very-Long-Period (VLP) seismic energy in near real time. With an efficient algorithm and adequate network coverage, accurate source locations of VLP energy are derived to quickly locate the shallow magmatic conduit system at Kilauea Volcano, Hawaii. During a restart in magma flow following a brief pause in the current eruption, the shallow magmatic conduit is pressurized, resulting in elastic radiation from various parts of the conduit system. A steeply dipping distribution of VLP hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the Halemaumau Pit Crater. The distinct hypocenters suggest the shallow plumbing system beneath Halemaumau consists of a complex plexus of sills and dikes. An unconstrained location for a section of the conduit is also observed beneath the region between Kilauea Caldera and Kilauea Iki Crater.

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USGS2004

Growth and collapse of Waianae volcano, Hawaii, as revealed by exploration of its submarine flanks

Wai‘anae Volcano comprises the western half of O‘ahu Island, but until recently little was known about the submarine portion of this volcano. Seven new submersible dives, conducted in 2001 and 2002, and multibeam bathymetry offshore of Wai‘anae provide evidence pertaining to the overall growth of the volcano's edifice as well as the timing of collapses that formed the Wai‘anae slump complex. A prominent slope break at ∼1400 mbsl marks the paleoshoreline of Wai‘anae at the end of its shield-building stage and wraps around Ka‘ena Ridge, suggesting that this may have been an extension of Wai‘anae's northwest rift zone. Subaerially erupted tholeiitic lavas were collected from a small shield along the crest of Ka‘ena Ridge. The length of Wai‘anae's south rift zone is poorly constrained but reaches at least 65 km on the basis of recovered tholeiite pillows at this distance from the volcano's center. Wai‘anae's growth was marked by multiple collapse and deformation events during and after its shield stage, resulting in the compound mass wasting features on the volcano's southwest flank (Wai‘anae slump complex). The slump complex, one of the largest in Hawai‘i, covering an area of ∼5500 km 2 , is composed of several distinct sections on the basis of morphology and the lithologies of recovered samples. Two dives ascended the outer bench of the slump complex and collected predominantly low-S tholeiites that correlate with subaerial lavas erupted early during the volcano's shield stage, from 3.9 to 3.5 Ma. Pillow lavas from the outer bench have Pb, Sr, and Nd isotopic values that overlap with previously published subaerial Wai‘anae lavas. On the basis of the compositions of the recovered samples, the main body of the slump complex, as represented by the outer bench, probably formed during and shortly after the early shield stage. To the southwest of the outer bench lies a broad debris field on the seafloor, interpreted to have formed by a catastrophic collapse event that breached the outer bench. A dive within the debris field recovered subaerially derived volcaniclastic rocks; analyzed glasses are tholeiitic and resemble early shield stage compositions. The breach may have then been filled by slumping material from the main volcanic edifice. Finally, atop the northern main body of the slump is a rotated landslide block that detached from the proximal part of Ka‘ena Ridge after the volcano's late shield stage (3.2 to 3.0 Ma). From the inner scarp of this block we recovered subaerially erupted tholeiitic pillow breccias and hyaloclastites that are systematically higher in alkalis and more fractionated than those collected from the outer bench. These rocks correlate compositionally with late shield-stage subaerial Kamaile‘unu lavas. None of the collected slump complex samples correlate with alkalic subaerial postshield lavas. Volcaniclastic rocks and glass disseminated in pelagic sediment, collected from north of Ka‘ena Ridge, originated from Wai‘anae's postshield stage and Ko‘olau's shield stage, respectively.

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