Estimates of the apparent quality factors Q_Lg (attenuation determined from the spatial decay of Lg waves) and Q_c; (attenuation determined from the temporal decay of seismic coda waves) are made for the crust of Virginia and its environs. The results are presented in the form Q_(Lg,C)(f) = Q₀f^N, where Q₀ = Q_(Lg,C)(1 Hz) and N represents the frequency dependence. The study area is located in the Appalachian region of Virginia and eastern Tennessee, containing three areas of regionally high seismicity: the central Virginia, Giles County, and eastern Tennessee seismic zones. The attenuation of the Lg phase was studied using vertical component digital recordings from Virginia Tech Seismological Observatory network stations. The seismic sources were ten regional surface mine explosions and six regional earthquakes. It was determined that Q_(Lg,C) can be represented by Q₀ = 186, σ_logQ₀ = 0.05, and N = 1.1 ± 0.1 for the frequency band 1-4 Hz. A site effect corrected estimate of Q_(Lg,C) was also determined for the study area. This was accomplished using a spectral ratio method in which station site effects and instrument responses are canceled out. For the frequency band 1-10 Hz the site independent apparent quality factor can be represented by Q₀=155, σ_logQ₀ = 0.1, and N=1.2±0.2. Station site factors were estimated using a mean residual technique. The decay of seismic coda waves across the Giles County, Virginia seismic network was studied to estimate Q_c for western Virginia. A relatively new spectral method was used. The seismic sources were four local earthquakes. For the frequency band 1-10 Hz, the results can be represented by Q₀= 111, σ_logQ₀ = 0.07, and N = 1.3 ± 0.07 . These values agree with a limited number of results obtained using a bandpass, time domain method which showed Q₀ = 132, N = 1.3. The results obtained for the Virginia area differ significantly in the 1 - 3 Hz range from those reported in most previous studies of the eastern United States. Previous studies have generally shown 800 ≤ Q₀ ≤ 1000 and 0.3≤ N≤0.5, but many of those results are for much larger regions and determined using different analysis techniques. Several reasons that could account for the different results include 1) estimates of attenuation may be affected by incorrect geometrical spreading models, 2) the size of the study area may affect the estimates, and 3) estimates of Q_(Lg,C) made for broad regions may be biased by zones of differing tectonic activity. Of these factors, only the effects of changing geometrical spreading coefficients and scattering models (related to study area) can be quantified. Neither of these affect the results by more than a factor of two. The high frequency dependence values (N≃1.1) are probably influenced by the lack of definition of higher frequency (≃10 Hz) data at the path distances studied. Future studies should employ more extensive data sets covering a larger geographic area. At greater distances, the attenuation of higher frequency waves may be more easily observable. The large frequency dependence values are probably indicative of an area where scattering dominates over anelastic attenuation. The folded and thrusted Appalachian provinces may, indeed, be such a region of high scattering. Such a mechanism may also help to explain southeastern United States meizoseismal areas that are small relative to the total felt areas. Large frequency dependence results for Q_Lg and Q_c are relevant with respect to seismic hazard. We do not believe the results are overly biased by station site effects or varying source effects and if they hold for magnitudes greater than those studied here (m < 4.2) , they indicate a greater potential for damage by higher frequency waves to engineering structures in Virginia and its environs than previously assumed. / Master of Science

Statement of the Problem The purpose of this study was to determine the need for establishing new vocational agriculture departments in public accredited county high schools in areas of Virginia which were not offering a vocational agriculture program. Problem Analysis An analysis of the problem listed the objectives of this study as: 1. To determine each public accredited county high school in Virginia in which there was a need for establishing a new vocational agriculture department. 2. To determine the number of teachers required in each of the new vocational agriculture departments needed. 3. To determine the total number of public accredited county high schools in Virginia in which there were needs for establishing vocational agriculture departments. 4. To determine the total number of teachers required in the new vocational agriculture departments needed. / Master of Science

A relocation study is made for 50 Virginia earthquakes (1959-1981) using a variation (JED/SE77) of the Joint Hypocenter Determination (JHD) method. Joint Epicenter Determinations (JED) were used in conjunction with a companion single event location program (SE77) to relocate hypocenters from data sets in the Giles County seismic zone (GCSZ) in southwestern Virginia and the central Virginia seismic zone (CVSZ). In the GCSZ six earthquakes, recorded both regionally and teleseismically and previously relocated jointly by Dewey and Gordon (1980), and nine earthquakes, recorded by a local network and individually located using the HYPOELLIPSE program (Lahr, 1979), were relocated. The JED/SE77 relocated hypocenters virtually all fall within the 70% confidence ellipses of the corresponding original hypocenters. In the CVSZ 25 events, originally located individually using HYPOELLIPSE, were relocated. The JED/SE77 relocations produce, for the most part, only small changes in epicenters (<5 km average displacement) and comparably small changes in focal depths. Geometrically, they can be grouped into three planes and one cluster of events. The majority (17/25) of the events are contained in two of the planes, both of which have an ENE trend and a 45° southerly dip. The JED/SE77 results: 1) indicate that the original HYPOELLIPSE hypocenters are quite accurate and should constitute the preferred hypocenters; 2) give added confidence to the instrumental definition of the GCSZ and the CVSZ; and 3) show by the depth distribution of foci that the entire upper portion of the crust is involved in the release of seismic energy. / Master of Science

Patterns of fossil diagenesis caused by groundwater leaching provide insight into how shells are altered. This study analyzes fossils in unconsolidated terrigenous sediments from the Virginia Coastal Plain, unlike previous studies conducted mostly in carbonate terranes. The vertical and lateral distribution of diagenetic states was mapped in an outcrop (63 m by 2.1 m) of the Yorktown Formation. A paleostream channel located at one end was incised during the Pleistocene and filled with sediments of the Shirley Formation. The Tabb Formation unconformably overlies the outcrop. Acidic groundwater caused the observed patterns of fossil and sediment diagenesis. These patterns include zones of fossil alteration, diagenetic stratification of the sediment, and fossil diagenesis on a microstructural level. Groundwater movement, controlled by the presence of the paleochannel, caused diagenetic alteration or complete dissolution of the fossils, and possibly caused precipitation of fine-grained iron oxyhydroxides. All carbonate material in the vicinity of the paleochannel is completely dissolved away, although iron oxyhydroxide coatings of fossils remain. Away from the paleochannel Crepidula fornicata (gastropod; aragonite), Ostrea sp. (bivalve; calcite), Balanus sp. (barnacle; calcite), and bryozoans (calcite) are found in parallel zones of alteration that dip toward the paleochannel and cut across horizontal sedimentologic and fossiliferous layers. Groundwater also leached the Yorktown sediments. This alteration caused a diagenetic stratification of the sediment, with unaltered greenish-gray silty fine sand along the base of the outcrop, overlain by leached yellowish-brown silty fine sand and areas of concentrated iron oxyhydroxides. The preservation of both aragonitic and calcitic shells was affected by groundwater movement. Original aragonitic shell material is found as chalky, uncrystallized specimens or neomorphosed shells, or is completely dissolved with only molds or ghosts remaining. Neomorphosed specimens typically consist of calcite-replaced shell material with pockets of original aragonite, and sparry calcite filling empty shell cavities. Original calcitic shell material is either chalky or unaltered. Chalky shells range from relatively hard to soft and pasty. Crepidula shells of intermediate chalkiness tend to separate into thin flakes, caused by dissolution along growth surfaces. Chalkiness of pasty shells is caused by dissolution of shell material (without recrystallization) and not simply loss of organic matrix. SEM photos of Crepidula reveal the more porous and leached appearance of chalky shells in contrast with hard; unaltered shells. The presence of chalky aragonitic and calcitic shells indicates that chalky textures are, to some degree, independent of mineralogy and microstructure. / M.S.

M.S.

M.S.

The angling public is a heterogenous aggregation of subgroups with differing value systems; therefore, fisheries managers must identify the subgroups and their corresponding attributes to guide management programs. This study was designed to evaluate the concept of recreational specialization for differentiating angler subgroups, and to determine if angler attitudes and management preferences vary predictably by specialization level. Specialization was defined as a continuum of angler behavior, from general to specialized, along four dimensions: (1) fishery resource use, (2) degree of experience, (3) investment, and (4) the relationship of angling to the lifestyle. In 1984-85, 544 anglers on the Shenandoah and New Rivers, Virginia, were interviewed and asked to participate in a followup mail survey. Of those who agreed, 379 anglers returned completed questionnaires (80% response rate). Cluster analysis of respondents, using variables in each of the four dimensions, identified six distinct angler types, ranging from low to high specialization. As expected, occasional and generalist anglers cited escape and family-oriented motivations, placed greater emphasis on luck to catch fish, were satisfied with catching and harvesting smaller fish, and favored liberal harvest regulations. Specialists were more likely to cite resource-oriented motives (testing skills, trophy fishing), to rely on skill to catch fish, preferred to catch and release larger fish, and favored restrictive harvest regulations. The results show that relatively simple and objective surveys of angler behavior can substitute for attitude surveys and can indicate how programs should be managed to maximize angler satisfactions. / M.S.

A need exists for the State of Virginia to have a data network for its televised distance education program. A combination of a terrestrial and a satellite data network can be utilized for the purpose. The network is analyzed and its strengths and weaknesses are presented. A data protocol has been written to control such a network. Delays and throughput of the network have been calculated. The leased telephone line network can be utilized for transferring data from distant class sites to Blacksburg. Six pages of text for 75 off-campus students can be transferred from distant class sites to Blacksburg using this network, in one hour. When the terrestrial network is used for voice and data communication at the same time, a delay of approximately 30 seconds is introduced between two voice connections. This delay is too high for a distance education network. The satellite data network should be utilized for transferring data from Blacksburg to all distant class sites. A very good 19.2 kbps carrier is available with bit error rate (BER) of 1E-6 or less. A very small aperture terminal (VSAT) network has also been proposed for the purpose. / Master of Science

M.S.

1. Purpose of the Study. The purpose of this study was to examine the priority status of institutional goals as perceived by students, faculty, and administrators in Virginia rural community colleges. The research questions were (1) What are the student, faculty, and administrator perceptions of the present ("is") priority of community college goals?; (2) What are the student, faculty, and administrator perceptions of the preferred ("should be") priority of community college goals?; and (3) What differences exist between the three reference groups between present and preferred perceptions of the priority status of goals? 2. Methods and Procedures. A questionnaire, based upon the Virginia Community College System stated goals, was developed to gather answers pertinent to the research. A random sample of 821 students and 91 faculty and all 70 administrators from six rural community colleges in Virginia responded to the questionnaire. Each respondent was asked to rate each of the 24 goals in terms of its present ("is") and preferred ("should be") importance along a continuum. Responses could vary along a five-point scale from a rating of one ("of no importance") to five ("of extremely high importance"). CONCLUSIONS 1. In general rural Virginia community college students, faculty, and administrators differed in their perceptions of the present and preferred priority status of the Educational Program and Operational Goals. Based upon this general finding, this study indicates a lack of widespread support for the priority of the institutional goals as developed by the Virginia Community College System. 2. All three reference groups indicated that nearly all of the goals should be of greater importance than they were perceived to be at the time of the study. This general finding supports the conclusion that goals are desired states which are not totally attainable. 3. To the extent that goal hiatus, as one component of Martorana and Kuhns Interactive Forces Theory accurately explains academic change, it appears that several goal priorities for the rural colleges within the Virginia Community College System are in a position to be rearranged. / ED. D.