A Reconnainsances Study to Delianate Conductive Groundwater Zone Using Resistivity Sounding in Some Part of Kwara State North-Central, Nigeria

From the results, three to four electrostratigraphic layers with resistivity value ranging from 44 to 997 ohm/m and thickness ranging from 0.5 to 39.7 m were observed in the study area. The top loose rocks, the weathered conductive zone, the fractured basement rock and the fresh basement rock of older granite suite were encountered respectively. From this research, it can be deduce that, the thicker top soil and deeper weathered basement rock at the depth of 30 to 45 meters within this area produce a productive site for sitting future borehole. Insufficient groundwater supply in some places leading to scarcity is noticed in VES 10, VES 12 and VES 13. H, I, and A curve types are generally the most common in the area and are typical of basement complex area. Geographical Positioning System tool (model: GPSmap 76CSx), was used to locate the VES points. Fifteen VES points with electrode spacing [AB/2] of 100 meters separation around Ndanaku and environs were undertaken using Schlumberger configuration. IPI 2 Win [1990-2003] Geosoft resistivity sounding software was used to model the field curves from the measured data on the field. Groundwater in the area is regarded as poor due to localized nature of the aquifer and the study aimed at addressing this scarcity of water within the area by studying the conductive zone and knows the aquifer types through resistivity sounding techniques for future drilling.

Electrical resistivity modeling around the Hidaka collision zone, northern Japan: regional structural background of the 2018 Hokkaido Eastern Iburi earthquake (Mw 6.6)

The Hidaka collision zone, the collision boundary between the NE Japan and Kurile arcs, is known to be an ideal region to study the evolution of island arcs. The hypocenter of the 2018 Hokkaido Eastern Iburi earthquake (Mw 6.6) in the western part of the Hidaka collision zone was unusually deep for an inland earthquake, and the reverse fault that caused the earthquake has an uncharacteristically steep dip. In this study, we used three-dimensional inversion to reanalyze broadband magnetotelluric data acquired in the collision zone. The inverted resistivity model showed a significant area of high resistivity around the center of the collision boundary. We also identified a conductive zone beneath an area of serpentinite mélange in a zone of high P–T metamorphic rocks west of the high-resistivity zone. The conductive zone possibly reflects areas rich in pore fluids related to the formation and elevation of the serpentinites. Sensitivity tests indicated the need for additional magnetotelluric survey data to delineate the resistivity distribution around the epicentral area of the 2018 earthquake although the resistivity model showed a conductive zone in this area.

ANALYSIS OF SHALLOW SUBSURFACE STRUCTURE AT GEOTHERMAL AREA OF IE JUE USING RESISTIVITY METHOD

It has been conducted a geo-electrical resistivity survey at geothermal area of Ie Jue, Aceh Besar. The survey aims to measure resistivity value in the area. It is expected that the values of resistivity will image the subsurface structure in the area. In addition geological features in the area are shown after we process it. The data acquisition in this study was acquired using a SuperSting R8/IP resistivitymeter and its data processing using EarthImager 2D software to get the image of resistivity pseudosection. The two lines of measurement crossed the surface geothermal manifestation. Each line has 330 m in length, and 56 electrodes with electrode space of 6 m. The result of resistivity pseudosection model interpreted based on geological condition and observation in the area. Resistivity pseudosection model shows the study is water-saturated (<64.0 Ωm) to a depth of ±65 m and a highly conductive zone (0.6-3.5 Ωm) with a thickness of 30-50 m. This conductive layers below the embodied surface at a distance of 158-160 m on the IJ-Y1 line and at a range of 130-185 m on the IJ-Y2 line. This conductive zone is indicated as a weak zone where geothermal fluids are transported to the surface.Keywords: Geothermal, Ie Jue, geo-electrical resistivity survey, resistivityREFERENCES Bennet, J.D., Bridge, D.McC., Cameron, N.., Djunuddin, A., Ghazali, S.A., Jeffrey, D.H., Kartawa, W., Rock, M.N.S., Thomson, S.J., Whandoyo, R., 1981. PetaGeologiLembar Banda Aceh, Sumatera, Puslitbang Geologi. Bandung.Syukri, M., Saad, R., Nordiana, M., & Azwin, I. 2014. Preliminary Study of Sumatera Fault Using 2-D Resistivity Imaging Method. Electronic Journal of Geotechnical Engineering, 19.Knödel, K., Lange, G., & Voigt, H.J., 2007. Environmental geology: Handbook of field methods and case studies: Springer Science & Business Media.Telford, W. M., Geldart, L. P., Sheriff, R. E. 1990. Applied Geophysics Second Edition, Cambridge University Press, USAMarwan, M., Rusydy, I., Nugraha, G.S. and Asrillah, A., 2014. Study of Seulawah Agam’s Geothermal Source Using Gravity Method. Jurnal Natural, 14(2)Asrillah, A., Marwan, M., Rusydy, I. and Nugraha, G.S., 2014. Application of Magnetics Method to Mapping the Geothermal Source at Seulawah Agam Area. Jurnal Natural, 14(2).Ismail, N.,Ramadhan, S., 2013. Karakterisasi Struktur Dangkal pada Lapangan Panas Bumi Seulawah Agam Menggunakan Metode Very Low Frequency (VLF). Prosiding Semirata FMIPA Universitas Lampung. Lampung, Indonesia.

Anatomical Characteristics of Garcinia lucida (Vesque) and Scorodophloeus zenkeri (Harms) Wood and Debarking Response in the South Region Cameroon

The aim of this work was to investigate the possible anatomical changes of Garcinia lucida and Scorodophloeus zenkeri after the removal of their bark. Debarking was done on individuals of each species at 1.30 m from the soil. The wound was rectangular in shape with 30 cm side. There was a follow-up every three months for nine months during which the survival and rate of regeneration of the bark were recorded. A block of cube was cut from the regenerated and intact wood of species for microtomy and microscopy activities. On the cross-section of each wood, vessel features like density and diameter were measured before and after wounding. Semi-automatic measurements were made using the SpectrumSee digital image analysis software. In the wood of the two species, it appeared that the density of the vessels before debarking was significantly comparable to the density after debarking, while the diameter of vessels in the regenerated wood was smaller. The cambial area increased slightly in the rainy season for all species. After nine months all the species started the restoration of their conductive zone. G. lucida heals its wound more rapidly than S. zenkeri.

DGPS AND MAGNETOTELLURIC CONSTRAINTS ON THE CONTEMPORARY TECTONICS OF THE SANTORINI VOLCANIC COMPLEX, GREECE

The study of vertical and horizontal crustal movements at the Santorini Volcanic Complex (SVC), as deduced by Differential GPS measurements revealed that an intricate pattern of five distinct domains with different horizontal kinematics: The West SVC (Akrotiri peninsula and Therassia) with very significant NNW-ward motion, North Thera with rather significant NW-ward motion, East Thera (Monolithos), with significant SE-ward motion, South Thera with significant NW-ward motion and, finally, central Thera with small westward motion. An apparently dextral, NNW-SSE oblique-to-strike-slip fault emerges as a prominent tectonic structure, separating the West SVC from the rest of the complex; this is the “Santorini Fault Zone”. Additional insight is afforded by the results of MT and GDS surveys: a significant NNW-SSE conductive zone was detected, which is collocated with the purported NNW-SSE fault zone indicated by DGPS analysis and may be explained as an epiphenomenal conductivity anomaly. The observed deformation pattern enables the drafting of a qualitative model of contemporary tectonics, which is also presented and discussed. The model is plausible but certainly incomplete and pending verification with numerical modelling and additional observations

Study on Failure Characteristic Simulation of Seam Floor for Coal Mining above Confined Aquifer Based on Fluid-Solid Coupling Theory

Water inrush is one of the main types of coal mine water disaster. Based on fluid-solid coupling theory, the confined water inrush numerical model is performed using FLAC3D program and similar simulation experiment, and the floor damage field and confined water vector field are simulated. The results show that, in the coupling action of mining stress and pressure of confined water, the mining floor was divided into four zones, namely the mining damage zone, effective confining protection zone, confined water soil-fluid coupling lifting zone, original confined water lifting zone. Confined water-conductive zone with the periodic roof pressure fluctuate, at each pressure and flowing zone height reaches the maximum, rise with height remained unchanged, the distribution shape of a "wave", water inrush is the results of effective connectivity of mining damage zone and Confined water-conductive zone, plate thickness of water-resisting layer exists or not, waterproof performance and the pressure of confined water inrush size is the key

An audio-magnetotelluric investigation of the Otjiwarongo and Katima Mulilo regions, Namibia

As an additional opportunistic component to the southern African magnetotelluric experiment, natural-source audio-magnetotelluric (AMT) data were acquired during phase IV to investigate the local-scale electric conductivity subsurface structure in the Otjiwarongo and Katima Mulilo regions (Namibia) as an aid in locating the installation points for high-voltage direct current earth electrodes. The study showed that the shallow subsurface of areas containing one measurement site in the Otjiwarongo region and three sites in the Katima Mulilo region have appropriate high conductivities for the optimal placement of the earth electrodes. Both of the AMT surveys are situated close to the edge of the orogenic Neo-Proterozoic Damara mobile belt (DMB). Previous studies all suggest the existence of a highly conductive midcrustal zone, which correlates well with the spatial location of the DMB. Two-dimensional inverse modeling of the Otjiwarongo AMT data confirms the existence of the high-conductive zone at midcrustal depths (10–15 km). The high conductivity of the DMB is explained by the presence of interconnected graphite in the marble units present. The Katima Mulilo inversion results are characterized by a conductive upper crustal layer that does not form part of the DMB conductive belt. It was deduced that at the uppermost subsurface (maximum [Formula: see text]), Kalahari sediments are responsible for the high conductivity observed, whereas at greater depth (up to 6 km), its cause remains enigmatic, albeit the hypothesis of ironstone or graphite being present and causing the observed conductive upper crust.

A Methodology for Geometry Generation of the Lower Conductive Zone of the Lung Airways and Simulation by Intermediate Boundary Conditions

This paper presents a general methodology for the development and simulation of a human lung between scales 0–16. The methodology is based on the simulation of only one of the two possible branches at each bronchiole. The operation of the truncated branches is included by means of a user-defined function. This function prescribes the velocity profile calculated for the active branches in the truncated ones in order to make the hydraulic losses equal between them. This procedure was tested between 0 and 7th generation by imposing the time profile of a real forced spirometry test in the trachea as boundary condition. The test showed a very good agreement between the numerical predictions and the spirometry data.

Spatial Distribution of Raffaelea quercivora in Xylem of Naturally Infested and Inoculated Oak Trees

Mass mortality of Japanese oak caused by Raffaelea quercivora due to Japanese oak wilt (JOW) has been tremendous since the late 1980s in Japan. We investigated detailed distribution of R. quercivora hyphae in a naturally infected Quercus serrata tree using fluorescein-conjugated wheat germ agglutinin and also examined spatial relationships between hyphal distribution, water conduction loss, and host reactions in xylem in inoculated Q. crispula saplings. Hyphae of R. quercivora elongated longitudinally in vessels and transversely in ray tissues in both naturally infected and inoculated Quercus trees. Hyphae were confined within a relatively small area near the inoculation site. Vessel dysfunction was also confined and overlapped with hyphal distribution. The reaction zone consisting of two types of fluorescent substance was formed surrounding the outside of the hyphal area in xylem and was always found in non-water-conductive zone. These results suggest that wilting of Quercus trees caused by JOW may not be induced by dysfunction of a small number of vessels, but by that of many vessels, and it requires that R. quercivora hyphae spread from many galleries bored by beetles during mass attacks.