Here's how you can explore and analyze subsurface geological structures using geophysical technology.

Structural seismic interpretation focuses on generating detailed maps of the underground structure by analyzing the spatial arrangement of arrival times in three dimensions. This method helps visualize and understand the geological formations beneath the Earth's surface. On the other hand, seismic sequence stratigraphic interpretation interprets the reflections seen in seismic data in relation to a conceptual model of repeated cycles of sediment deposition and their subsequent geological processes. This approach aids in reconstructing the history of sedimentary sequences and understanding how they were formed over time.

Seismic surveys are the most utilized geophysical measurement for analyzing subsurface structures such as faults, folds, and lithological beddings. Seismic survey is very effective for detecting faults, and showing bedding plane orientation and continuity.In recent studies,seismic surveys have been used to locate ground water, indications of locations for landfills, and characterization of how an earthquake-prone area will shake during an earthquake. Seismic survey is based on two main methods, shallow seismic refraction(<100 feet) and shallow seismic reflection(between 65 and 100 feet).

To expand on the diverse use of geophysics, particularly the electrical resistivity approaches, I would like to mention the use of these methods in the determination of the depth to bedrock. This parameter is generally needed in many engineering projects, specifically civil and heavy construction projects. Highlighting on how effectively this can be achieved, I recommend the integration of two or more of the geophysical methods. For instance, combining methods such as ERT and MASW can help in understanding near surface site conditions for engineering projects. The MASW can give information about the Vs of the subsurface lithologies and can model Vs profile for the area, whilst the ERT gives you an idea of the depth at which bedrock lies.

Gravity surveys are geophysical methods to measure Earth’s gravitational field variations at different locations. Gravity surveys use the measurement of the gravitational acceleration at the Earth’s surface expressed in terms of milligals (mGal) or microgals (μGal). Higher-density materials such as rocks and minerals exert a stronger gravitational forces than low-density materials like water or air. As such, by measuring the variations in densities, we can infer the distribution of different lithologies and sub-surface geological structures.

GPR has evolved to be best used Geophysical methods and is used by different departments nowadays such as Archeological studies,environment, mining,bedrock and pavement surveys,forensic sciences etc. Ground Penetrating Radar (GPR) uses pulses of high-frequency radio waves to detect and map changes in the sub-surface. It is a non-intrusive survey technique. A change in the velocity results in a reflection in the GPR data. The difference in the permittivity of the two materials governs the strength of the reflection; therefore, a pulse travelling from limestone into a void generates a much stronger reflection than a pulse travelling from limestone into sandstone.

1. Data Acquisition The first step is to gather geophysical data using various methods such as seismic surveys, gravity measurements, magnetic surveys, and electrical resistivity tests. Each method provides different insights based on the physical properties of subsurface materials. 2. Data Processing Raw geophysical data often contain noise and require processing to enhance signal quality. Techniques like filtering, stacking (in seismic data), and corrections for instrumental and environmental factors are applied to improve data reliability. 3. Data Interpretation Interpreting geophysical data involves visualizing and analyzing the processed data to identify patterns and anomalies that suggest subsurface features.