HIG Technical Reports

Permanent URI for this collection

https://hdl.handle.net/10125/16317

News

For information about HIGP please contact:
Hawai‘i Institute of Geophysics and Planetology
School of Ocean and Earth Science and Technology
University of Hawai‘i
1680 East-West Road
Pacific Ocean Science & Technology (POST) Building, Room 602
Honolulu, HI 96822
Office Phone: 808.956.8760
Fax: 808.956.3188
Dr. Peter J. Mouginis-Mark, Director
www.higp.hawaii.edu

Browse

Now showing 1 - 10 of 19

Proposal to conduct analysis of seismic activity on the Kilauea East Rift Zone
([s.n.], [n.d.]) Cooper, Patricia; Moore, Gregory
Sections: Geophysics and Budget.
Geothermal resources assessment program : geosciences proposal
(Hawaii Institute of Geophysics, University of Hawaii at Manoa, 1992) Thomas, Donald M.
Sections: Geology Program and Budget
Geochemical precursors to seismic activity
(Hawaii Institute of Geophysics, University of Hawaii at Manoa, 1988) Thomas, Donald M.
Studies of earthquake precursory phenomena during the last several decades have found that significant geophysical and geochemical changes can occur prior to intermediate and large earthquakes. Among the more intensely investigated geochemical phenomena have been: (1) changes in the concentrations of dissolved ions and gases in groundwaters and (2) variations in the concentrations of crustal and mantle volatiles in ground gases. The concentration changes have typically showed no consistent trend (either increasing or decreasing), and the spatial and temporal distribution of the observed anomalies have been highly variable. As a result, there is little agreement on the physical or chemical processes responsible for the observed anomalies. Mechanisms proposed to account for precursory groundwater anomalies include ultrasonic vibration, pressure sensitive solubility, pore volume collapse, fracture induced increases in reactive surfaces, and aquifer breaching/fluid mixing. Precursory changes in soil gas composition have been suggested to result from pore volume collapse, micro-fracture induced exposure of fresh reactive silicate surfaces, and breaching of buried gas-rich horizons. An analysis of the available field and laboratory data suggests that the aquifer breaching/fluid mixing (AB/FM) model can best account for many of the reported changes in temperature, dissolved ion and dissolved gas concentrations in groundwater. Ultrasonic vibration and pressure sensitive solubility models cannot reasonably account for the geochemical variations observed and, although the pore collapse model could explain some of the observed chemical changes in groundwater and ground gas, uncertainties remain regarding its ability to generate anomalies of the magnitude observed. Other geochemical anomalies, in particular those associated with hydrogen and radon, seem best accounted for by increases in reactive surface areas (IRSA model) that may accompany precursory deformation around the epicenter of an impending earthquake. Analysis of the probable response of these models to the earthquake preparation process, as well as to other environmental factors, suggests that geochemical monitoring programs can provide information that may be valuable in forecasting the probability of an earthquake; however, because of the complexity of the earthquake preparation process, the absolute prediction of seismic events using geochemical methods alone, does not presently appear to be feasible.
Correspondence between Donald Thomas, geologist at the University of Hawaii at Manoa, and the Department of Health, State of Hawaii, regarding the geothermal well drilling operation and ground water contamination
(Department of Health, State of Hawaii, 1989) Thomas, Donald; Lewin, John C.
From the cover memorandum: "We are enclosing copies of recent correspondence with Donald Thomas of the Hawaii Institute of Geophysics regarding potential impacts of geothermal well drilling operations and expressing his views on the viability of monitoring to determine the impacts of the well on existing aquifers. Because of your interest in geothermal work, we believe that you will find the information highly interesting and useful in your deliberations on the subject."
A time-domain electromagnetic survey of the East Rift Zone, Kilauea Volcano, Hawaii
(Colorado School of Mines, 1974-10) Skokan, Catherine King
A time-domain electromagnetic survey was conducted over the East Rift Zone of Kilauea Volcano, Hawaii. The purpose of the survey was two-fold. First, the survey was intended to give greater insight into interpretation techniques of time-domain electromagnetic data. Secondly, a more complete picture of the geologic structure and hydrology of the Rift, with special emphasis on its geothermal potential, was to be gained. To interpret the time-domain electromagnetic data, first the maximum-received voltages were converted to apparent resistivities and mapped. Next, the received transients were matched with a catalog of asymptotic curves. Then, theoretical layered-earth curves were calculated and the transients were again matched. Finally, use of a least-squares-fit computer program gave a more exact interpretation. Although the asymptotic curves have been calculated for no more than a three-layer case, the theoretical matching technique may be expanded to a greater number of layers.
A preliminary geothermal evaluation of the Mokapu Peninsula on the island of Oahu, Hawaii
(Hawaii Institute of Geophysics, University of Hawaii, 1982-06) Hawaii Institute of Geophysics, University of Hawaii at Manoa
Preliminary geological, geochemical, and geophysical field surveys have been conducted on Mokapu Peninsula on the island of Oahu in an effort to determine whether sufficient indications of geothermal potential exist within or adjacent to the peninsula to justify further, more detailed, exploratory efforts. An evaluation of existing geologic data as well as recently completed mapping on Mokapu indicate that the peninsula is located on the edge of or immediately adjacent to the inferred caldera of Koolau volcano. There are at least three post-erosional volcanic vents located on the peninsula and several more form small islands adjacent to it. The age of this post-erosional activity has been estimated to be at least 400,000 years before present. The post-erosional events, on the basis of mineralogical and geochemical evidence, are not considered to have been a renewal of the older (1.8 million years before present) Koolau activity, but rather were a series of independent, short-lived eruptive episodes. Geochemical investigations conducted within and around the Mokapu Peninsula included mercury-soil surveys and radon ground-gas surveys as well as a limited evaluation of groundwater chemistry. Numerous difficulties were encountered in the interpretation of the soil-gas geochemical data because of the high degree of cultural activity associated with the U.S. Marine Corps Air Station at Kaneohe; however, one area in the southwest quadrant of the peninsula was tentatively identified as a low-order geochemical anomaly in which observed levels of mercury and radon were both significantly higher than background values. These anomalous values were tentatively attributed to increased soil permeability or possibly to slightly elevated subsurface temperatures. Groundwater sampling on Mokapu Peninsula was severely restricted because of the absence of wells within the study area and thus water chemistry analyses were limited to the Nuupia fish ponds. Samples obtained in the fish ponds were found to be seawater diluted with varying amounts of fresh groundwater. Although no thermal alteration of the water chemistry was evident for this area, an evaluation of existing groundwater chemical data for adjacent areas to the south and east of Mokapu suggests that some low-level thermal alteration may be present within shallow aquifers overlying the inferred Koolau caldera. Schlumberger resistivity soundings were completed in three locations on the peninsula: KVSI, in the northeast quadrant within the Ulupau crater, KVS2 in the northwest quadrant along the main jet runway, and KVS3 in the southeast along Mokapu Road. At KVSl a relatively high resistivity was encountered to a depth of approximately 20 meters below sea level, which was underlain by a basement resistivity of about 2 to 3 ohm-meters. At KVS2 and KVS3 similar resistivities of 2 to 3 ohm-meters were detected at much shallower depths (approximately equivalent to local sea level) below a thin, moderately resistive layer having an impedance ranging from 15 to 118 ohm-meters. Although the basement resistivity values are somewhat lower than would be expected for seawater-saturated basalt, and therefore could be interpreted as arising from a thermal anomaly, it is considered far more probable that the resistivities observed correspond to a low-resistivity seawater-saturated clay layer underlying the peninsula. In the context of the geothermal potential of the Mokapu Peninsula, the results of the present survey can be summarized as follows: 1. The geological data suggest that the post-erosional volcanism associated with the Mokapu Peninsula was of such a short duration and is of such great age that it is considered unlikely that significant remnant heat would be found beneath these structures. Although remnant heat may still be present within the magma chamber of Koolau volcano, there is presently no geologic evidence to substantiate its occurrence. 2. The geochemical data available indicate that one area within the peninsula may be slightly anomalous; however, no firm conclusions can be drawn concerning its relationship to a potential heat source. Limited groundwater geochemical data for the peninsula do not suggest the presence of thermally altered groundwater although some indication of groundwater anomalies have been identified several kilometers to the south of Mokapu Peninsula. 3. The results of geophysical surveys suggest that the peninsula is underlain by seawatersaturated clays at local ambient temperatures. The probability of there being an exploitable high-temperature resource beneath the Mokapu Peninsula is extremely low, and the probability for a low-temperature resource, at economically viable depths, is also very low.
Thermal process of the east rift of Kilauea from geophysical data
(Hawaii Geothermal Project, 1975-03-11) Furumoto, Augustine S.
This is a short note summarizing results of geophysical surveys over the East Rift of Kilauea. Details on data and methods of analysis are being compiled for a later more comprehensive report.
Geothermal resource assessment for Hawaii
(Geothermal Resources Council, 1979-09) Thomas, Donald M.
The preliminary phase of a geothermal resource assessment program for the State of Hawaii has been completed. Several locations on all the major islands of the Hawaiian chain have been identified as potentially having a geothermal reservoir within a few kilometers depth of the surface. Although geological and geophysical data were of some use in the regional surveys, groundwater chemical data was far more helpful in identifying more restricted areas in which to carry out site specific field surveys. Geochemical and geophysical surveys are presently underway in several of the areas identified as potentially having a geothermal resource.
Geothermal resources assessment in Hawaii : final report
(Hawaii Institute of Geophysics, University of Hawaii at Manoa, 1985) Thomas, Donald M.
This document summarizes the available geologic, geochemical, and geophysical data for all prospective geothermal resource areas on all islands in Hawaii current to 1985.
Chloride/magnesium ratio of shallow groundwaters as a regional geothermal indicator in Hawaii
(Hawaii Institute of Geophysics, University of Hawaii at Manoa, 1979) Cox, Malcolm E.; Thomas, Donald M.
Because of the complex geological and hydrological conditions and the virtual lack of thermal springs, regional geothermal investigations in Hawaii require the use of techniques substantially different from those conventionally applied in other geothermal environments. The large number of hydrological wells in the state provides an appreciable source of groundwater chemical data. However, largely because of the island environment, interpretation of much of these data as geothermal indicators becomes ambiguous. Initially, SiO2 and temperature of groundwaters were used to identify thermally anomalous zones, but on a regional basis it has been found that these criteria are not always successful. As a further criterion for assessment, the Cl/Mg ratio of the groundwater has been used. On a state-wide basis, this ratio has been successful in further "screening" the SiO2-temperature selected sites, and in defining more specific areas which warrant further investigation. Temperature, SiO2 and Cl/Mg values for nearly 400 groundwater samples are included.

Browse

Recent Submissions