Wondering How Geophysics Can Help You in Your Project? Geophysics is a vast field of science that has applicability in various fields, namely engineering projects, environmental projects, groundwater and hydrological projects, mining, archaeology, and forensic projects. It fundamentally involves determining the subsurface conditions of a given part of the Earth to identify how safe the area is for the intended operation or even discovering buried ore resources and minerals. Geophysics can benefit most subsurface related projects by helping to minimize risks while saving costs and time.
But first, the basics: what does Geophysics entail?
What is Geophysics? Geophysics is a non-invasive investigation of the Earth's subsurface characteristics by measuring and analyzing points at the surface. It is non-invasive, meaning it doesn't require the Earth to be drilled or excavated; instead, what's below the surface is remotely sensed using advanced technologies. The Earth is literally scanned.
Through geophysical surveys, you can detect human artifacts, minerals, groundwater, rocks, CO2 deposits, etc. In a simpler description, you get an image of what the Earth looks like underneath.
The use of geophysics is becoming more relevant than ever in the field of construction and engineering. Imagine spending hours drilling a hole for an engineering project only to discover the soil structure is unstable 2 meters below. By conducting a geophysical survey before and when drilling a hole, you reduce uncertainty and errors.
Geophysical surveys can help to: 1. Map out suitable areas for pipelines, cables, windmills, and tunnel construction
2. Assess risks of earthquakes and landslides in a given area
3. Identify and map potential CO2 deposits underneath the Earth's surface
4. Map out CO2 injections within the Earth
5. Locate and retrieve valuable resources like crude oil, metallic ore deposits and groundwater
6. Study large geological areas to discover more data about the Earth.
Many unforeseen disasters, such as structural collapse, can be avoided by studying the characteristics of the subsurface layers of the proposed structure. Sadly, the effort, time, and cost of excavating and drilling far into the Earth to carry out studies can be discouraging. Thanks to geophysics, these challenges are reducing.
In the following sessions, we see why that is. How Investment in Geophysical Surveying Can Help Reduce Project Cost As opposed to other soil test methods, geophysical methods are able to continuously scan subsurface layers. Due to this continuity, these methods can detect very tiny areas through which water may pass into the foundation of buildings. Furthermore, geophysical methods can determine the soil type present depths below the surface, the presence of voids, and the thickness of fill. Piezometers can accomplish this same task, but you would require several units of the equipment because each piezometer can only detect soil conditions at a specific point. Procuring many piezometers amounts to a higher cost. Geophysics eliminates the need for piezometers, thereby saving costs. Although test trenches may also work, they only provide soil information along a single profile.
But that's not all, geophysical surveys are quiet, requiring nothing more than two people to handle. This reduces labor costs. In contrast, test trenches require considerable excavation using heavy equipment. Drilling and excavation also run the risk of damaging underground utilities and incurring repair costs. In summary, geophysics reduces project costs by allowing the exploration of large areas with relative ease and speed.
How Geophysics Helps Saves Time When it comes to environmental projects, time is of the essence. For example, it may be necessary to complete construction or repair work quickly to prevent escalation or deterioration. Weather conditions may also compel engineers to expedite completion. Sadly, quality geotechnical tests, no matter how critical, may be sacrificed for time. That doesn't have to be the case, thanks to geophysics.
Geophysical methods are non-invasive and won't interrupt traffic within and behind the structure where the test is to be done. This prevents the need to put a project on hold because of unavoidable business operations. Excavation, which usually takes time, is also avoided. Moreover, there will be no need to waste valuable time boring and testing several holes out of uncertainty.
A geophysical survey takes a shorter time than trenching and boring. Scanning an area behind a building using geophysical methods may take only three days, while processing may take six days. On the other hand, boring and trenching typically takes several days up to weeks, depending on equipment available, weather conditions, and traffic issues, among other factors.
Geophysics Can Help Reduce Risks and Save Lives
By identifying potential weak points in the soil structure, engineers can foresee and prevent potential catastrophes in the proposed structure. Geophysics enables engineers to locate the best possible site for environmental projects, reducing the loss of lives due to structural instability. Geophysical surveys locate utility lines below the Earth so there is less risk of damaging them during excavations, such as when drains need to be installed. Since geophysical methods preclude boring and trenching, that risk is eliminated.
Geophysical Surveying Methods Geophysical methods work by applying certain types of force to the ground and deducing the Earth's properties from the resulting energy using geophysical equipment.
Some Popular geophysical methods include: Magnetic Method The magnetic method involves measuring magnetic field variations of the Earth, which are related to certain subsurface rocks and mineral structures. For example, ores containing magnetic materials such as magnetite can be detected using the magnetic method of geophysical exploration.
Electromagnetic Method (EM) The EM method uses a transmitter and receiver coil suspended above the ground. The coil creates a primary electromagnetic field which induces a secondary field in the Earth that is proportional to the conductivity of the subsurface structures and can be used to detect rock type, minerals, groundwater, contamination, etc.
Electrical Resistivity In the electrical resistivity method, a current is driven into the Earth using electrodes, and then the resulting distribution of potential differences is measured using a sensitive voltmeter. Bedrocks can be mapped with this method.
Induced Polarization (IP) Induced polarization is the Earth's ability to hold charges for some time. Different subsurface geological structures hold charges for varying lengths of time. So when current is passed into the Earth, this geological method measures that length of time using electrodes. IP can help to locate clay, gold, and other chargeable minerals.
Seismic Reflection Method Seismic geological surveys are done by administering a percussive force to the ground, which gives off seismic waves. The waves reflect or refract anytime a structure is encountered, denoting the geology of that area. This method can identify subsurface conditions at great depths over a large area.
Radiometric Method Radiometric geophysical surveys are airborne methods that measure the amount of radiation the Earth produces. That's because radioactive substances such as uranium and potassium occur in rocks, sending considerable amounts of detectable rays. When the radiation is measured, you can determine the geology.
The Bottom Line Safety, cost, and time are key considerations for any groundwater, engineering, archaeology, environmental project, and geophysics addresses each of these areas. So if you wish to save time and minimize costs for your next project, a geophysical survey can be the ideal solution. At Hephzibah Geosolutions, we try to understand your project and make suggestion of best geophysical techniques and help in carrying out a detailed geophysical surveying for your project. You can call us today to discuss your project with us.