Open Access Original Research Article

Bouguer Anomaly of Geothermal Reservoir at Tiris Area, Probolinggo, East Java, Indonesia

Salman Hamja Siombone, Sukir Maryanto, . Wiyono

Journal of Geography, Environment and Earth Science International, Page 1-18
DOI: 10.9734/jgeesi/2021/v25i930304

Research related to the geothermal system in the Tiris geothermal area (TGA) Probolinggo Regency has been conducted using the gravity method. This study aims to investigate the subsurface structure, with a target on estimating geothermal reservoir rocks from the study area. This study utilized the Gravity meter La Coste & Romberg type G-1503 on 116 acquisition points in an area of 2.16 km2, covering all geothermal manifestation points in TGA. The gravity measurement data obtained is then processed through gravity corrections, which include: conversion into milli-Gals (mGal) units, tidal correction, drift correction, latitude correction, free air correction, Bouguer correction, and terrain correction. These corrections to obtain a complete Bouguer anomaly (CBA) value. The study area shows the CBA value on a horizontal plane which ranges from 0.1 mGal to 4.2 mGal. The separation of the regional and residual Bouguer anomaly from the CBA on a horizontal plane employed the Moving Average method through spectrum analysis. The value of residual Bouguer anomaly ranges from -0.7 mGal to 2.7 mGal. The low anomalies are scattered in the northwest, and a small number are spread in the northeast and southeast, while the high anomalies are in the middle of the study area. The result of 3D inversion modeling finds that the study area's subsurface structure consists of four rock layers, namely lapilli tuff, tuffaceous breccia, volcanic breccia, and basalt. Volcanic breccia is approximated as geothermal reservoir rocks at a depth of 700 to 1000 meters below the acquisition point. In contrast, basalt is supposed to be intrusive igneous rock because it tends to break through the surface at a depth of 348 to 350 meters below the acquisition point. The presence of these intrusive rocks can be predicted through spectrum analysis result, which shows a regional anomaly source at a depth of 348 meters below the acquisition point. This intrusion rock is suspected to be a heat source rock in the geothermal system in the study area.

Open Access Original Research Article

Characterization of Agropastoral Dam Lakes in the Bounkani Region, Côte d’Ivoire

Ettien Yah Carine, Yao Koffi Blaise, Kouame Koffi Fernand, Oga Yéi Marie-Solange

Journal of Geography, Environment and Earth Science International, Page 19-30
DOI: 10.9734/jgeesi/2021/v25i930305

The North-East region (Bounkani) of Côte d'Ivoire is the least watered region of the country with an average annual rainfall of 945 mm. The rainfall deficits observed in Côte d'Ivoire since 1970s could constitute a real threat to the environment and to water resources in general, and to dam lakes in particular. The main aim of this study was to follow the evolution of the dam lakes in the region over the years, i.e,(1986, 2002 and 2017) with reference to their spatial distribution (their densities and their limnological ratios). The approach adopted consisted of mapping and monitoring through remote sensing technology which involves processing satellite images for automatic extraction of these agropastoral structures on the various images. The results showed that these dam lakes were unevenly distributed both at the level of the departments and the watersheds, with 73.43% in the Black Volta and 28.57% in the Comoé. The density was higher in Doropo and varied from one department to another from 1986 to 2017, for the department of Bouna, it ranged from 9.34.10-4 to 3.74.10-3 per km2. The departments of Doropo and Tehini showed 1.51.10-3 to 1.01.10-2 per km2 and 1.05.10-3 to 4.53.10-3 per km2 respectively. Nassian department displayed a value of 1.42.10-3 per km2 and remained constant from 2002 to 2017. Like the density, Doropo Department had the highest limnological ratio which changes from 7.09.10-5 to 2.71.10-4 per km2 over the same period. The mapping of these agropastoral structures showed 18 agropastoral structures where 57 (28.07%) were functional or even contained water in the dry season in the region in 2017 including 2 in Nassian; 4 in Tehini; 9 in Doropo and 3 in Bouna.

Open Access Original Research Article

Assessment of Oil Spillage Impact on Vegetation in South-Western Niger Delta, Nigeria

Umar Wakil Adamu, Emmanuel Yeboah, Isaac Sarfo, Edward Kweku Nunoo, Clement Kwang, Foster Kofi Addai, Collins Oduro, George Darko, Grace Chikomborero Ndafira, Michael Batame, Emmanuella Aboagye Appea

Journal of Geography, Environment and Earth Science International, Page 31-45
DOI: 10.9734/jgeesi/2021/v25i930307

The present study assesses the impact of oil spillage in the Southwestern Niger Delta of Nigeria over the past fifty (50) years. It further sought to find out the driving forces and implications of oil spillage on vegetation, livelihoods and other key parameters. The study employed geospatial techniques and a secondary source of data to achieve the objectives set out in this study. The Global Moran I statistical tool was used to determine the spatial autocorrelation based on feature locations and attribute values. We observed built-up areas, bare land, and less dense vegetation had an overall increment of 1975.98 km2, 1370 km2 and 23805 km2, respectively. Dense vegetation had declension of 22058.33 km2 over the past five decades. Findings depict a declining trend in Normalized Difference Vegetation Index, attributed to oil spillage as the key contributory factor. Occasioned by anthropogenic activities, the driving forces were traced to attacks on oil pipelines during conflicts and illegal means of creating leakages to siphon crude oil for sale. To achieve sustainability in oil spill management in the Delta, the study recommends further research to ascertain the cost of losses incurred apply geospatial techniques to monitor and predict environmental changes that inform decisions of key actors.

Open Access Original Research Article

Flood Vulnerability Assessment on Selected Communities in Ikwerre Local Government Area of Rivers State, Nigeria, Using Remote Sensing and GIS Techniques

E. Wali, P. O. Phil-Eze, C. H. Wizor, M. Abdullahi, O. O. Afolabi, Ihunda. C. Eze, L. C. Bosco-Abiahu

Journal of Geography, Environment and Earth Science International, Page 46-57
DOI: 10.9734/jgeesi/2021/v25i930308

A flood is an overflow of water that submerges land that is usually dry. Flooding may occur as an overflow of water from water bodies, such as river, lake or ocean, in which the water overtops or breaks levees, resulting in some of that water escaping its usual boundaries, or it may occur due to an accumulation of rain water on saturated ground in an area. To find out the most vulnerable communities, the Digital Elevation Model (DEM) and location data of selected communities were used. The Image Re-class and Map Overlay were performed on QGIS software to identify communities that are most affected. The result shows that the region has no river channel that discharge excess water easily. It also shows that four, out of twelve settlements were located at the high risk zone. The settlements are Uniport, Omuoda, Omuahunwo and Okparagwa. It was recommended that the high risk zone in the area should be provided with artificial water channel that will contain and convey surface sun-off to a nearby stream. The local authority should relocate the affected settlements to a safer zone.

Open Access Original Research Article

Geophysical Investigation of Groundwater Using Vertical Electrical Sounding in Mubi and Maiha Local Government Areas of Adamawa State, North Eastern Nigeria

S. Kasidi, V. Victor

Journal of Geography, Environment and Earth Science International, Page 58-76
DOI: 10.9734/jgeesi/2021/v25i930309

This research work is aimed electrical resistivity survey for groundwater development conducted in Mubi and Maiha local government area of Adamawa State, in order to delineate the groundwater potential zones and determining the depth and thickness of sediments layers, and recommend suitable depth for drilling. Fourteen vertical electrical soundings (VES) were carried out within the study area using Schlumberger electrodes configuration was used for the field data acquisition. The field data obtained was analyzed using IX1D computer software and, VES1-14 resistivity model indicate 3-4 layered earth models. The interpretation shows positive inference in terms of a well-defined weathered basement and as such, it is likely to possess requisite hydro-geological characteristics that could supply underground water in fair quantity to well when drilled. Therefore, VES number denoted (R) are recommended for drilling at approximate depths of 40±5 to 50±5 meters.