Time Lapse Seismicity Study of the Sub Sahara West Africa and the Gulf of Guinea Region | Chapter 07 | Research Developments in Science and Technology Vol. 1

 A time lapse seismicity map of the Gulf of Guinea and Sub-Saharan west African region from 1918 to 2017, covering a total of 89 years, provided an in-depth understanding of seismic activity in the studied region. This is with the primary goal of evaluating the regional seismicity distribution through time and helping us to critically comprehend the seismogenic zones in order to estimate the region's earthquake danger in the future. The data was divided into five (5) seismic windows: 1918-1937, 1938-1957, 1958-1977, 1978-1997, and 1998-2017. We deduced that there has been an increase in seismicity from 1958 to the present day. The increase in reported seismicity could be due to an increase in the number of installed seismometers capable of detecting both small and large magnitude events, or it could indicate that the region is nearing an active phase of seismicity. Intraplate seismicity was felt in the area as a result of seismic waves being transmitted from the mid Atlantic ridge (plate boundaries separating the African from the South America). The depth distributions of the FPS, projected depth view, and nodal plane projection, as shown in the depth section plots of the selected fault plane solutions (FPS) of the four identified major fractured zones investigated in Eluyemi et al. (2019), reveal a shallow seismogenic source of events in the study region. The orientation of the pressure and tensional axes, on the other hand, aids in understanding the geometrical and mechanical classification as well as the expected direction of the region's stress field.

Author(S) Details

Ayodeji Adekunle Eluyemi
Centre for Energy Research and Development (CERD), Obafemi Awolowo University (OAU), Ile-Ife, Nigeria and Geosciences and Technology Division, CSIR–North East Institute of Science and Technology (CSIR-NEIST), Jorhat-785006, Assam, India and Academy of Scientific and Innovative Research (AcSIR), CSIR–North East Institute of Science and Technology (CSIR-NEIST) Campus, Jorhat-785006, Assam, India.

Awosika Damilola Doctor
Physics Department Adeyemi College of Education, Ondo State, Nigeria.

Adebisi Oluwakemi Deborah
Department of Building, Obafemi Awolowo University (OAU), Ile-Ife, Nigeria.

Saurabh Baruah
Geosciences and Technology Division, CSIR–North East Institute of Science and Technology (CSIR-NEIST), Jorhat-785006, Assam, India and Academy of Scientific and Innovative Research (AcSIR), CSIR–North East Institute of Science and Technology (CSIR-NEIST) Campus, Jorhat-785006, Assam, India.

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A Modelling Approaches for Vortex Theory and Earth Dynamics | Chapter 3 | Challenging Issues on Environment and Earth Science Vol. 5

 Morphological evidence from active tectonic areas with subcircular geometries suggests that these geometries are the result of mechanisms other than those described by translational dynamics of complex faults. Endogenic forces, particularly convection currents, have yet to be fully explained. Under certain conditions and due to Coriolis Force, magma upwelling from the mantle, which differs in density from upward flows developing in the atmosphere and in water, can trigger endogenic vortexes. At their onset and ascent phases, vortexes apply lateral forces as a result of rotation, opening their way toward the surface and eventually stabilizing the channel. as opposed to a Vortex flows unload materials from the outside and compact them on the channel's lateral surface, making it more regular and stable. Rising linear flow compacts overlaying materials, inhibiting surge; vortex flows unload materials from the outside and compact them on the channel's lateral surface, making it more regular and stable. Torsional movements on the surface can be seen associated with volcanites, lateral ramps, and subcircular elevations. Another phenomenon that could be caused by vortex dynamics is volcanic cones with pseudo-rotations in the morphologies surrounding the crater. In this paper, we propose a model for a vortex theory that could explain Earth dynamics in terms of spiraling movement and magma upwelling stabilizing over time.

Author (S) Details

Valentino Straser
UPKL Department of Science, Environment and Energy, 4 Brussels, Belgium.

Alessandro Ferrari
Sant’Ilario d’Enza, Italy.

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