The high-resolution seismic method can provide acoustic reflectivity images of shallow marine geology structures. In South Vietnam, the demand for construction materials like sand is high; therefore, the exploration of its deposits is considered in this study. This study investigated an around 200-square-kilometer area offshore Bac Lieu using 2D seismic sub-bottom lines. We employed the processed seismic amplitude and its seismic attributes as mean and variance textures to interpret the data. The processed seismic amplitude and its attributes can represent the young Holocene sediments (i.e., sand, silt, clay, and their mixtures) thanks to their different seismic patterns. Our interpretation result consists of 3D horizons of the seabed, Holocene silt, and sand sediments, which are compatible with the prior geological information, including three nearby drill holes. The seabed gradually descends from 10.0 m to 19.0 m over a horizontal distance of around 11 km. Moreover, the interpreted results show that the sand sediments reside in the center of survey area, with a maximum thickness of around 12.0 m. Interestingly, a fill sediment channel effectively separates two different zones of young Holocene sand and silt sediments. The findings provide valuable information for Vietnamese government officers to develop sustainable policies and regulations for marine mineral exploitation and exploration.
26 December 2020 in Science and Technology Development Journal-Natural Sciences
Ground penetrating radar method (GPR) is common place in imaging buried objects, such as: supply water and drainage systems, electric and telecom cables. For shallow geology, GPR method has provided high-resolution sections containing subsurface information. In processing data, the velocity of GPR wave is the most important parameter. It helps to exactly specify the structure of a geology sections. Defining a wrong velocity may lead to an erroneous result. In this research, we are going to present two processing steps to define the electromagnetic wave velocity and the position of object from GPR data that was acquired by using a shield antenna machine prototype. The first step is application of Kirchhoff migration and energy difference graphs to calculate the electromagnetic wave velocity. In the second step, the result of migrated sections consisting of hyperbole diffraction was evaluated. If migrated using the right velocity, the diffracted hyperbola will focus on its peak and have the maximum energy. Finally, we used the workflow to define the velocity, the position and the size of the object from real GPR data collected at Go Vap district, Ho Chi Minh City, Vietnam.
Research on deep geological structures is becoming increasingly important when needs of deep mineral resources is increasing. The most effective geophysical methods for deep exploration are magnetotellurics (MT) and seismic methods. Analyzing MT and seismic data provides valuable deep structures insights into the geophysical environment. However, a geophysical inversion method often faces non - uniqueness of solutions when it can produce a range of inverted models that provides great misfits. In this paper, we propose a inversion processing technique that utilizes known information from seismic data to build a suitable conductivity model. First, the seismic data provide the geological boundary. Next, we construct a weight matrix that incorporates this boundary information to guide the inversion process. Finally, the obtained inversion result includes details about the resistivity and boundaries of the geological environment. Our cooperative technique is tested using MT and seismic data collected from the Queensland region, Australia. The resulting inverted images provide critical information about the boundaries and resistivity of the rock within this area.