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What are the differences between seismic reflection and refraction methods in geophysics and how are they used to study the Earth's subsurface?
Seismic reflection and refraction are two methods used in geophysics to study the Earth's subsurface.
Seismic reflection involves sending seismic waves into the ground and recording the reflections that bounce back from different rock layers. This method is used to create images of subsurface structures like faults, rock layers, and oil and gas reservoirs.
Seismic refraction, on the other hand, involves measuring the bending of seismic waves as they pass through different rock layers. This method is used to determine the velocity of seismic waves in different materials, which can help in mapping the depth and thickness of subsurface layers.
Both methods provide valuable information about the Earth's subsurface, helping geophysicists understand the composition and structure of the ground beneath our feet.
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What is it called when a seimic waves bounces backward when it reaches a boundary?
When a seismic wave bounces backward when it reaches a boundary, it is called reflection. This phenomenon occurs when the wave encounters a change in medium or boundary, causing it to change direction and return to its source. Reflection is a key process in seismic imaging and is used to map subsurface structures in geophysics.
What is bouguer correction?
Bouguer correction is a method used in geophysics to account for the gravitational attraction of material between the measuring point and the center of the Earth. It is applied to gravity measurements to remove the effects of terrain and topography, allowing for a clearer interpretation of subsurface geology or mineral deposits. Bouguer correction helps to isolate the gravity anomalies caused by subsurface features.
What is it called when s sesmic wave bounces backward when it reaches a boundary?
Reflection.
What is a basal reflection?
As a geological reference, the basal reflection is referring to the bottom layer. In a seismic profile at the cross section of the subsurface, the basal reflection would be a particular dense layer at the bottom of the formation.
What is distance amplitude correction?
Distance amplitude correction is a technique used in geophysics to adjust seismic data for the effects of attenuation, which causes signal amplitude to decrease as the distance from the source increases. By applying correction factors to compensate for this loss of amplitude, the seismic data can be more accurately interpreted and better reflect the true subsurface properties.
Which method uses the density differences of rocks to interpret subsurface structures?
Seismic reflection is the method that uses the density differences of rocks to interpret subsurface structures. It involves sending seismic waves into the ground and measuring the reflections to create a picture of the subsurface geology based on the different densities of rock layers.
What geophysical method is commonly applied in oil exploration?
Seismic reflection is commonly used in oil exploration to map subsurface geological structures and identify potential oil and gas reservoirs. This method involves sending seismic waves into the ground and recording the reflected waves to create images of the subsurface.
What is basic principle and their application of electrical method of applied geophysics?
The basic principle of electrical methods in applied geophysics is to measure the electrical properties of subsurface materials to infer information about the geology and structure of the Earth. This is done by injecting an electrical current into the ground and measuring the resulting potential differences. The applications include mapping subsurface features such as bedrock, groundwater levels, mineral deposits, and detecting contaminants.
What is it called when a seimic waves bounces backward when it reaches a boundary?
When a seismic wave bounces backward when it reaches a boundary, it is called reflection. This phenomenon occurs when the wave encounters a change in medium or boundary, causing it to change direction and return to its source. Reflection is a key process in seismic imaging and is used to map subsurface structures in geophysics.
What is the main purpose of stacking in seismic refraction and reflection method?
The main purpose of stacking in seismic refraction and reflection methods is to improve the signal-to-noise ratio of the seismic data by summing and averaging multiple traces. This helps enhance the quality and clarity of subsurface images, making it easier to interpret geological layers and structures.
When were seismic graphs invented?
Seismic graphs were first used in the early 20th century, with the first recorded reflection seismograph shot taken in 1921. The use of seismic graphs revolutionized the field of geophysics by allowing scientists to study the subsurface structure of the Earth by analyzing reflected seismic waves.
What is bouguer correction?
Bouguer correction is a method used in geophysics to account for the gravitational attraction of material between the measuring point and the center of the Earth. It is applied to gravity measurements to remove the effects of terrain and topography, allowing for a clearer interpretation of subsurface geology or mineral deposits. Bouguer correction helps to isolate the gravity anomalies caused by subsurface features.
What is the difference between reflection and refraction seismic methods?
Reflection and refraction seismology are both ways to study the structure of the Earth near the surface. Among other things, they are used to search for oil and gas deposits. Reflection seismology works like sonar. You send a sound pulse into the Earth. The sound pulse is probably most often made by setting off an array of small explosive charges, but it could be from trucks that balance on a plate and vibrate that plate to send a waveform into the ground, or for measuring soil layers near the surface it could even be done by pounding on a metal plate with a sledgehammer. The sound pulse goes down into the Earth. Each time it hits a rock layer, soil layer, or other object with different acoustical properties (sound speed and material density) than the one above, part of the energy reflects back toward the geophones, the sound detection devices, you have arranged across the surface. You can record these reflections. Making a few assumptions about sound speed in the subsurface and other matters, and after doing a lot of computer processing, you can build up a picture of the underground structure. Refraction seismology uses a sound pulse and a line of geophones extending away from it to the side. The sound pulse goes into the ground. Some of the energy gets refracted into each of the various rock or soil layers in the ground and moves through them horizontally, and some of the energy is always refracting out of those layers again and returning to the surface, where the geophones detect it. In general, deeper rock layers have higher sound velocities than shallower ones. Therefore at first the earliest signal to reach the geophones will be the direct wave through the surface layer, but at geophones further away a wave that goes down into the Earth, gets into a layer that has a faster sound velocity, and after a while returns to the surface will be the wave that reaches the geophones first. You can take the arrival times of different wave paths at your geophones and calculate out a structure of the rock and soil layers, with the thickness and sound velocity of each. Reflection seismology needs a lot of data processing, so it wasn't that popular until computer power increased enough to make it practical. In general refraction seismology is good for finding the general structure of an area, while reflection seismology is good at finding small details. They really work best when you use them together. The sound velocity data you can get from refraction seismology can be applied to the reflection seismology, and can make it more accurate than it would have been otherwise.
Technology used to find out the different layers of the earth?
Seismic imaging technology, such as seismic reflection and seismic refraction, are commonly used to map the different layers of the Earth. This technology utilizes sound waves to create images of the subsurface layers based on the reflection and refraction of these waves as they pass through different materials with varying densities. Additionally, drilling cores and well-logging tools are also used to provide direct samples and data for studying the Earth's layers.
How dsp is used in reflection seismology?
In reflection seismology, digital signal processing (DSP) techniques are used to enhance and analyze seismic data collected from the Earth's subsurface. DSP helps in filtering out noise, improving signal-to-noise ratio, and enhancing the resolution of seismic images. By applying DSP algorithms, geophysicists can accurately interpret subsurface structures and identify potential oil and gas reservoirs.
What is seismic profilling useful for?
Seismic profiling is useful for identifying subsurface structures and characteristics by analyzing the reflection and refraction of seismic waves. It helps in locating potential oil, gas, and mineral deposits, as well as understanding the geology of an area for engineering and construction purposes. Seismic profiling is also used in assessing seismic hazards and risks for earthquake-prone regions.
Use geophysical in a sentence?
Geophysics in the vicinity has revealed other buildings and the excavation has started on the main villa building.
