Honors Projects for Geology and Geophysics
Permanent URI for this collection
Browse
Recent Submissions
1 - 10 of 11
-
ItemIn the Wake of Fukushima: Cesium Inventories of selected North Pacific Fish(University of Hawaii at Manoa, 2016-08)To this day there are global efforts in evaluating the effects in wake of the 2011 Fukushima Nuclear Power Plant disaster. The estimated 500 tons of contaminated wastewater that entered the nearby marine ecosystem (Watabe 2013) was dispersed into the Pacific Ocean and due to biological uptake in migratory fish species (Madigan 2012) was detected in the water as well as in fish as far as the West coast of US. The FDA accepted intervention limit for cesium isotope intake is 300 Bq/kg annually for fish. The question we are left with is how much cesium is in the fish we consume, a thought the community of Hawai’i should consider since our fish products are caught in the Pacific Ocean. Thirteen most commonly consumed types of locally bought fish samples were analyzed using gamma spectroscopy to measure Fukushima-derived 134 Cs and 137Cs isotopes. All fish samples had detectable 137Cs and nine out of the thirteen samples had detectable 134 Cs, an isotope indicative of Fukushima releases. The highest 134 Cs and 137Cs concentration in the examined species was the Ahi tuna carrying 0.098 Bq/kg and 0.62 Bq/kg respectively. The highest concentrations occurred in high trophic level species with migratory patterns from Japan to Hawai’i or residing in the most northern Pacific Ocean. Nine out of the thirteen samples showed traces of 134 Cs, with only five of those activities outside the range of uncertainty. All activities are significantly below intervention limits but are informative to the community on what is being consumed. Results should also provide a basis for future work on cesium bioaccumulation in fish.
-
ItemMap Location and Dimensional Definition of Subsurface Caverns(University of Hawaii at Manoa, 2014-09-26)This study attempts to locate and define a small-scale, shallow subsurface cavern by the use of a gravity micro-survey in which station spacings of about 10 feet are used. The results show that two caverns exist underneath Kuilei Lane. They are filled with water and strike in a N. 15° E. direction. One cavern is 12 feet high, 38 feet wide in cross section, and has 4 feet of rock separating the roof from the ground surface. The second cavern is separated 9 feet laterally from the first cavern and is 8 feet high, 14 feet wide in cross section, and has 5 feet of rock between the roof and the ground surface. Lack of time and operational knowledge prevented direct verification of the results by drilling.
-
ItemFluorescent Microspheres as Proxies for Microorganism in a Deep Subseafloor Tracer Transport Experiment(University of Hawaii at Manoa, 2014-09-26)There is growing evidence that the subseafloor biosphere extends throughout the immense volume of aging basement underlying the global system of mid-ocean ridge flanks and ocean basins. The umbrella Tracer Transport experiment will be conducted by injecting fluorescent microspheres into a borehole on the flank of Juan de Fuca Ridge and monitoring their arrival at all of the observation boreholes. Microsphere transport rates obtained from this experiment will provide a basis for evaluating the origin of microbes observed in 3.5 million year old sediment-buried basement. In this experiment, the fluorescent microspheres are used as proxies for microorganism. Colloid tracers such as fluorescent microspheres are used to characterize flow rates and preferred flow paths of groundwater, and to gain information about the subsurface transport of microbial pathogens, or other colloidal contaminants. The objective of my thesis is to study the compatibility of these microspheres to the ocean basement environment for the tracer transport experiment, by defining their detection limits within the context of deep basement environment by the detection methods available, studying the characteristics of the microspheres and studying the behavior of colloid tracers through a basalt core. From the detection limit experiment, the minimum concentration detected for the fluorescence microscopy method is 10 microspheres/ filter and for the flow cytometry method is 40 microspheres/ ml. The two methods yield very similar results. Microspheres also clump significantly at high concentrations. The size and fluorescence of the microspheres remain unaffected by light, salinity, temperature (4 to 60 °C) or pressure (up to 80 bars).
-
ItemComparative Analysis of Terrestrial and Martian Volcanic Features Using Multispectral Thermal Infrared Images, Aerial Photographs and Viking Images(University of Hawaii at Manoa, 2014-09-26)The process of collecting information about an object without physically being in contact with it is often referred to as remote sensing. The utility of remote sensing in fields such as geology, geography, engineering and environmental studies is rapidly increasing with technology. Thirty years ago, being able to study the Earth and other planets through remote sensing was merely a dream. We were already realizing the benefits of utilizing air photography in solving scientific problems. We began obtaining information from images beyond the visible portion of the electromagnetic spectrum. Today, we are able to sense data from space and conduct global, uniform studies on planetary bodies. For the geologist, the field of remote sensing opens up a whole new level of interpretation. Inaccessible areas of the Earth and other planetary bodies can now be studied uniformly with increasing detail. In studying planetary bodies, remote sensing is currently the best option. The field of "planetary geology", geology applied to other planets and bodies, is growing rapidly as technology increases our ability to obtain information about other planets. We have built up our knowledge of the solar system, beginning with the early telescopes of Galileo and on to advanced radiotelescopes. Optical telescopes are still very useful for obtaining data from the Moon, which is relatively close to the Earth. However, in some applications, earth-based observations in geology have been nearly exhausted or planets further away or those obscured in any way, we must rely spacecraft images, which offer up to 1000 times better resolution (Siegal and Gillespie, 1980) in the case for Mars.
-
ItemThe Arid Lowland Vegetation of the Hawaiian Islands (1778-1825) as Recorded by the Early European Voyagers(University of Hawaii at Manoa, 2014-09-26)In this paper an attempt will be made to demonstrate principally on the basis of selected historical evidence, that such natural vegetation as might have existed in the arid lowlands of Kona, Lahaina, Honolulu and Waimea on Kauai, had been extensively modified by the native Hawaiians prior to the arrival of the first Europeans in 1778. Reliance will be placed on historical sources to show that at the time of first foreign contact with the Hawaiian islands that extensive areas within the arid lowlands had been cultivated with such food crops as breadfruit, bananas, taro and yams. It would further be argued that these various forms of vegetation, around which a large part of traditional Hawaiian subsistence agriculture revolved, were in turn gradually destroyed, by introduced animals and plants, by erosion resulting from log hauling, by lava flows, by substitution of higher revenue crops, by the movement of population from rural areas to urban areas and last but not least by the demise of the native Hawaiian population. Both from library sources and from observational field work done for this paper some description will also be offered of the nature of the vegetation which presently characterizes the areas under discussion. The ‘arid lowland' for the purpose of this research may be described in the words of William Hillebrand as the open country which is rainless during the greater part of the year; and today has a few native species but great quantities of introduced plants such as algaroba and haole koa. This is a dry and dusty region and generally lies on the leeward sides of the islands from sea level to about 2,000 feet.
-
ItemInfluence of Sediment Composition on Redox Speciation Within A Hawaiian Coastal Fishpond(University of Hawaii at Manoa, 2014-09-26)In aquatic systems, benthic microbial respiration can have a profound effect on nutrient cycling and overall ecosystem health. Respiration results in the release of bioavailable nutrients as well as series of redox species which can be used as a proxy to identify reduced benthic conditions. He'eia Fishpond, located in Kane'ohe, Hawai'i, is a low energy, shallow coastal system influenced by an influx of both riverine freshwater and marine seawater, as well as by mangrove forests located along its terrestrial periphery. Voltammetric solid-state microelectrodes were used to simultaneously identify and measure changes in redox speciation over time in dark incubations of fine grained to coarse grained sediment core samples taken from the pond. The primary objective of this study was to evaluate the synergy between sediment heterogeneity (i.e., varying grain size, permeability, mineralogy and organic matter content) and sediment redox chemistry. In addition, because coring and relocating sediment samples can lead to confounding effects within sediment cores, voltammetric microelectrodes were also used in a separate experiment to investigate the correlation between sediment core sample conditions and in situ conditions. Redox chemistry profile measurements taken in situ were compared to redox chemistry profile measurements taken from a sediment core sample collected from the same location. The in situ versus core experiment revealed that voltammetric sediment core profiles replicate in situ profiles to within ± 2.5 mm. Sediment cores for the dark incubations were taken from four sites within the pond along a gradient of fine grained to coarse grained sediment with a range of organic matter input. Major sources of organic matter input to the pond include mangrove, macroalgae and phytoplankton. As expected, incubation results showed that sediments most rich in fresh organic matter, those sites in close proximity to the mangroves, are most likely to induce rapid benthic respiration, resulting in increased production of reduced organics. In contrast, sediments containing less organic matter, the sandy sites with more of a marine end member influence, are likely to induce slower benthic respiration and less production of reduced organics. Also, there was indication that sediment at the pond under the greatest riverine influence are iron rich. This is significant because reductive dissolution of iron oxyhydroxides results in the release of both reduced iron and bioavailable phosphorus. Under anoxic sediment conditions, free reduced iron is likely to sequester sulfide via pyrite precipitation and phosphorus that enters sediment pore water is liable to flux upward into overlying waters. Phosphorus diffusion into phosphorus limited overlying water can lead to increased primary productivity and eventually hypoxic water column conditions. Consequently, results of this study, in conjunction with nutrient budget studies and further investigation into end member input, can prove useful when developing future sustainability management practices at He'eia Fishpond.
-
ItemDetermining Factors that Influence Turbidity in Kaneohe Bay, Oahu(University of Hawaii at Manoa, 2014-09-26)In recent years, much attention has been given to suspended particulate matter (SPM) concentrations, or suspended load, due to its potential impact on reef ecosystems. Solids are transported through the ocean and can have both detrimental (through sedimentation) and beneficial (supplying nutrients) effects on a coral reef community. This project seeks to identify the marine physical mechanisms that influence SPM concentrations in the reef environment of Kaneohe Bay. An acoustic Doppler current profiler (ADCP) was used to measure a number of water properties over the coral reef that extends across the mouth of Kaneohe Bay. The benefit of the ADCP is that it allows researchers to not only measure water current velocities throughout the entire water column, but it also enables this sampling to occur over extended periods of time. Sampling occurred during three separate deployments. The third ADCP deployment occurred in conjunction with field sampling with a Niskin bottle in hopes of calibrating measured ADCP values of acoustic backscatter with SPM concentration from filtered samples. Analysis of the ADCP data showed significant variation in the echo intensity (EI) signal, which can be used as an analogue for turbidity, between the ADCP sites. Current speed and wave height exhibited a covariant relationship with EI data, with higher EI values typically associated with higher waves and faster currents. Surprisingly, Sites 0-2 exhibited a diurnal cycle in EI levels, suggesting that marine biota may constitute a significant portion of the scatterers responsible for the EI data. It was not possible to confirm this hypothesis however, due to minimal data regarding the actual composition of the SSC at the time of deployments. The strongest relationship was found to be the EI response to vertical current velocities, themselves exhibiting a diurnal cycle. This relationship was not present at Site 3. The mechanism for vertical currents appears to be related to the incoming tide. There was a poor correlation between EI, as measured by the ADCP, and the filtered water samples from the third experiment. This was likely due to high spatial variations in reef characteristics and the inherent difficulty in measuring relatively small changes in suspended load.
-
ItemA Review of the Structure of Mid-Ocean Ridge Systems with Applications to the Tectonic History of the Northeast Pacific(University of Hawaii at Manoa, 2014-09-26)The physical properties of mid-ocean ridge systems are determined primarily through the use of thermal models. It was found that a leaky transform fault could be described by using a similar method. The stability of these ridge systems depends on the stress field that is acting upon them. Mid-ocean ridges can undergo substantial deformation which can be brought about by changes in the stress field. Such an effect is expected to be greater as a ridge gets in close proximity of a trench. In the case of the northeast Pacific, the model of Atwater (1970) for the tectonic history of the region is not compatible with the observed magnetic data, under the assumption that major changes in the stress field should be mirrored in the magnetic anomalies. A newer model in which the East Pacific Rise reaches the trench at 24 myBP is presented here. Such a model requires that the trench remain for another 4 m.y. before converting into a transform fault.
-
ItemEnumeration of Hydrothermal Plume Microbes(University of Hawaii at Manoa, 2014-09-26)Microorganisms play an integral part in hydrothermal plume ecosystem dynamics. Enumeration of microbial cells is needed to quantify microbial biomass. Epifluorescence microscopy with nucleic acid staining has been used satisfactorily to count plume microbial populations. The enumeration process would be enhanced by flow cytometry, which offers rapid, sensitive, and automated enumeration. However, enumeration was not possible in initial analysis of hydrothermal vent plume samples via flow cytometry. This research illuminates two aspects of the mineral rich hydrothermal plume that are limiting enumeration via flow cytometry: the non-specific binding of nucleic acid stains to mineral surfaces and mineral autofluorescence. In addition, preliminary results are shown of methods to eliminate minerals from hydrothermal plume samples.
-
ItemA Petrologic Study of the 1982 Summit Lavas of Kilauea Volcano, Hawaii(University of Hawaii at Manoa, 2014-09-26)This study presents detailed petrography, mineral analyses, and wholerock major and trance element analyses of the Kilauea Volcano summit lavas erupted in April and September 1982. It supplements earlier U.S. Geological Survey wet chemical major element analyses of the rocks. The purpose of this study is to identify the petrologic process(es) responsible for chemical variations in the lavas, and compare the chemistry of the 1982 lavas to those of previous Kilauea summit eruptions. The result show that the lavas erupted in April are chemically homogeneous. Lavas from the shorter but more voluminous September eruption vary systematically during the eruption from higher to lower MgO content. Computer modeling of the geochemical data indicates that olivine with minor clinopyroxene fractionation is probably responsible for the variation in lava compositions. The nearly aphyric nature of the lavas negates the possibility of olivine accumulation to explain the variation. Magma mixing in also an unlikely mechanism because the variations are nonlinear. The lavas from the two 1982 eruptions may be related to a common parental magma, although there are some differences in Ni between the magmas. The April lavas are very similar in composition to other historic lavas erupted in the central area of Kilauea caldera. The MgO range in the lavas from the brief September eruption represents about half of the total MgO variation of lavas erupted inside the caldera during historic time (after 1790).