Acoustics
of sedimentary/igneous section, Gulf of Aqaba coastal area, Egypt, and their applications
to seismic hazards
Abd ElMaktader A. ElSayed
Dept. Geophysics, Fac. Sciences, Ain Shams Univ. Cairo, Egypt |
Eighty five rock samples were collected from
both sedimentary and igneous sections between Dahab and Taba, Gulf of Aqaba coastal area.
Several petrophysical parameters were measured and calculated for some of the samples as:
Porosity, density, velocities of elastic wave propagation, Piosson's ratio, Young's
modules, bulk modules, rigidity, and specific acoustic impedance by which earthquake
energy and seismic moment can be estimated.
Graphical plots have been constructed to throw light on the most reliable and applicable
relationships for enhancing models used in seismic hazards studies. Vertical profiles of
some measured petrophysical parameters show how much they are uniform and homogeneous as
related to the sedimentary facies. Several linear models were calculated, characterized by
high coefficient of correlation by which we can calculate a significant parameter from
others which are usually measured during routine petrophysical analysis.
In the present work, shear wave velocity from the compressional wave velocity for both
sedimentary and igneous sections can be calculated. In addition, using the apparent
specific gravity considered as routine measurement, the rock rigidity, rock bulk modules
and compressional wave velocity can also be estimated. The acoustic impedance can
therefore be outlined with high accuracy from routine porosity measurements using the
calculated linear model. The present work has its applications to seismic hazards and
engineering constructions.
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