300+ TOP Geo Physics Interview Questions [REAL TIME]

1. What Scales Are Used For Magnitude? For Intensity?

• Seismic scales
• Environmental Seismic Intensity scale (ESI)
• European Macroseismic Scale (EMS)
• Liedu.
• Medvedev–Sponheuer–Karnik (MSK)
• Modified Mercalli (MM)
• PHIVOLCS Earthquake Intensity Scale (PEIS)
• Shindo.

2. How Does The Richter Scale?

The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs.

3. What Is The Difference Between Magnitude And Intensity?

Intensity:
The severity of earthquake shaking is assessed using a descriptive scale – the Modified Mercalli Intensity Scale.

Magnitude:
Earthquake size is a quantitative measure of the size of the earthquake at its source. The Richter Magnitude Scale measures the amount of seismic energy released by an earthquake.

When an earthquake occurs, its magnitude can be given a single numerical value on the Richter Magnitude Scale. However the intensity is variable over the area affected by the earthquake, with high intensities near the epicentre and lower values further away. These are allocated a value depending on the effects of the shaking according to the Modified Mercalli Intensity Scale.

4. What Is The Richter Magnitude Scale?

The Richter magnitude scale (also Richter scale) assigns a magnitude number to quantify the size of an earthquake. The Richter scale, developed in the 1930s, is a base-10 logarithmic scale, which defines magnitude as the logarithm of the ratio of the amplitude of the seismic waves to an arbitrary, minor amplitude.

5. What Is The Magnitude And Intensity Of An Earthquake?

The intensity is a number (written as a Roman numeral) describing the severity of an earthquake in terms of its effects on the earth’s surface and on humans and their structures. Several scales exist, but the ones most commonly used in the United States are the Modified Mercalli scale and the Rossi-Forel scale.

6. What Is The Magnitude Of An Earthquake?

Magnitude is a measure of the amount of energy released during an earthquake. It may be expressed using several magnitude scales. One of these, Used in Southern California, is called the Richter scale.

7. What Are The Costs Of Geophysics?

Cost is, of course, a key consideration. Most Environmental and Engineering Geophysical surveys have a cost structure that is similar to that of any licensed professional: an hourly consulting fee plus equipment rental costs. In addition, there are associated costs of mobilization (since most geophysical surveys require acquisition of data in the field), instrumentation amortization, data processing and interpretation, and report writing and presentation.

Ultimately, the application of geophysics must be assessed in terms of its projected costs and benefits as indicated above. EEGS professionals are trained to advise in developing cost and benefit assessments. It makes no sense to conduct a geophysical survey if the costs are projected to exceed any possible economic gains, or to exceed the project’s operational budget. In general, however, geophysical surveys are almost always substantially less expensive than traditional non-technical means of investigation such as excavation or drilling.

8. How Are Geophysical Methods Applied In Practice?

The implementation of geophysical methods is a structured process that consists of a number of key steps, including:

Initial evaluation of the problem at hand (i.e. what is the suspected problem, what initial information is known about the site, what additional information is required, and what are the desired outcomes)

Determination of which geophysical method (or combination of methods) will yield the optimal results. Not all methods will be applicable as noted in some of the links above, therefore, it is critical to carefully assess which methods are most likely to provide data and information relevant to the problem of interest. Also, while some methods may provide information, they may not be cost-effective in a particular context.

Identification of the scope (or size) of the required geophysical coverage.

Assessment of the way in which the data and information are to be acquired, interpreted and presented so as to address the issue at hand.

After these basic questions have been answered and the project approved, the geophysical work will commence.

Typically, Environmental and Engineering Geophysics consists of field surveys conducted along oriented lines (i.e. survey grids) over the desired area of interest. For more information on field surveying, you may want to refer to the links provided above in the “What Geophysical Field Methods are Available” section.

9. What Geophysical Methods Are Available?

Horizontal loop electromagnetic apparatus is used to locate conductive zones that may be leachate plumes. As noted previously, geophysical methods as applied to Environmental and Engineering Geophysics were derived from other principal areas of subsurface investigation, including petroleum, mineral and groundwater exploration. 

The methods or techniques most commonly employed by practitioners include:

• Electromagnetics.
• Gravity.
• Ground penetrating radar (GPR).
• Magnetics.
• Resistivity (and / or induced polarization).
• Seismic refraction (and / or near surface seismic reflection).
• Spontaneous potential (or “SP”).
• Induced polarization (or “IP”).

10. What Are The Benefits Of Geophysics?

Data from very low frequency electromagnetics have been converted to electrical current density and depth. The dark blue color indicates the core of a leachate plume emanating from a landfill. Environmental and Engineering Geophysics offers a unique window into the earth as a means of detecting sub-surface conditions, and its relevancy lies in the concrete and cost-effective benefits it delivers. These include:

Non-destructive :
 It is ideal for use in populated areas, such as cities, where many of today’s environmental and engineering issues arise. It also means an archeological site can be examined without destroying it in the process.

Efficiency :
 It provides a means of evaluating large areas of the subsurface rapidly.

Comprehensiveness : 
Combinations of methods (i.e. multi-disciplinary methods) provide the means of applying different techniques to solve complex problems. The more physical properties that are evaluated, the less ambiguous the interpretation becomes.

Cost-effective :
 Geophysics does not require excavation or direct access to subsurface (except in the case of borehole methods where access is typically by drilled holes). This means vast volumes of earth can be evaluated at far less cost than excavation or even grid-drilling methods.

Proven : 
The majority of techniques have been in existence for more than a half-century and are mature, yet still relatively undiscovered and underutilized by decision-makers who face complex environmental and engineering problems.

11. What Are The Types Of Problems Addressed?

The sledge hammer provides a source of energy for determination of the depth to water table and bedrock. Generally, environmental and engineering problems fall into the following classes or types:

• Infrastructure (highways and bridges)
• Groundwater (exploration and contaminant mapping)
• Geohazards (earthquake mitigation and collapse structure mapping)
• Urban (utility mapping, underground storage tank location)
• Geologic Mapping
• Archeology
• Forensics (i.e., illegal burials, etc.)
• Civil Engineering / Non-Destructive Testing (NDT)
• So-called “Brownfield” and Landfill Investigations
• Unexploded Ordnance (UXO detection and characterization)
• Dam Safety

12. What Is Geophysics?

The subsurface site characterization of the geology, geological structure, groundwater, contamination, and human artifacts beneath the Earth’s surface, based on the lateral and vertical mapping of physical property variations that are remotely sensed using non-invasive technologies. Many of these technologies are traditionally used for exploration of economic materials such as groundwater, metals, and hydrocarbons.

13. Give A Formula Which Relates Wavelength And Frequency?

The equation that relates wavelength and frequency for electromagnetic waves is: λν=c where λ is the wavelength, ν is the frequency and c is the speed of light.

14. Where Do The Shallow Earthquakes Occur?

Most earthquakes are a result of fault movement in the crust, a relatively thin layer on the Earth’s surface. In Cascadia, most earthquakes are shallow quakes that occur within the crust of the North America plate to a depth of about 20 miles (35 km).

15. What Causes A Deep Focus Earthquake?

A deep-focus earthquake in seismology is an earthquake with a hypocenter depth exceeding 300 km. They occur almost exclusively at oceanic-continental convergent boundaries in association with subducted oceanic lithosphere.

16. What Causes Earthquakes?

Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little.

17. What Is Meant By A Diurnal Cycle?

A diurnal cycle is any pattern that recurs every 24 hours as a result of one full rotation of the Earth with respect to the Sun. In climatology, the diurnal cycle is one of the most basic forms of climate patterns. The most familiar such pattern is the diurnal temperature variation.

18. What Are Diurnal Changes?

Diurnal temperature variation is the variation between a high temperature and a low temperature that occurs during the same day.

19. What Are Magnetic Storms?

A disturbance of the magnetic field of the earth (or other celestial body).

20. What Causes The Earth’s Oblateness?

The Earth’s oblateness, shown here as a bulge at the equator (highly exaggerated to demonstrate the concept) causes a twisting force on satellite orbits that change various orbital elements over time. The force caused by the equatorial bulge is still gravity.

21. Define Declination, Inclination.

Magnetic declination is the angle between magnetic north (the direction the north end of a compass needle points) and true north. The declination is positive when the magnetic north is east of true north. Magnetic inclination is the angle made by a compass needle when the compass is held in a vertical orientation.

22. Define Curie Temperature.

The Curie temperature (TC), or Curie point, is the temperature at which certain materials lose their permanent magnetic properties, to be replaced by induced magnetism.

23. What Is A Tomographic Image?

Tomography refers to imaging by sections or sectioning, through the use of any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, astrophysics, quantum information, and other sciences.

24. What Part Of The Earth Does Not Receive Direct P Waves From A Quake?

The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core.

25. What Is Seismic Imaging?

Seismic imaging is a tool that bounces sound waves off underground rock structures to reveal possible crude oil– and natural gas–bearing formations. Seismologists use ultrasensitive devices called geophones to record the sound waves as they echo within the earth.

26. What Is A Harmonic Tremor?

A harmonic tremor is a sustained release of seismic and infrasonic energy typically associated with the underground movement of magma, the venting of volcanic gases from magma, or both.

27. What Is Seismic Tomography?

Seismic tomography is a technique for imaging the subsurface of the Earth with seismic waves produced by earthquakes or explosions. P-, S-, and surface waves can be used for tomographic models of different resolutions based on seismic wavelength, wave source distance, and the seismograph array coverage.

28. What Are Sv And Sh Waves?

S-waves polarized in the horizontal plane are classified as SH-waves. If polarized in the vertical plane, they are classified as SV-waves. When an S- or P-wave strikes an interface at an angle other than 90 degrees, a phenomenon known as mode conversion occurs.

29. What Is A Seismograph And How Does It Function?

A seismograph is the device that scientists use to measure earthquakes. The goal of a seismograph is to accurately record the motion of the ground during a quake.

30. How Does A Seismograph Works?

Seismographs can detect quakes that are too small for humans to feel. During an earthquake, ground-shaking seismic waves radiate outward from the quake source, called the epicenter. Different types of seismic waves travel at different speeds and through different parts of the Earth during a quake.

31. Distinguish Between A Seismograph And A Seismogram?

A seismogram is a visual record that is created by a seismograph. A seismograph is a piece of equipment that records earthquake movements. These two items go hand in hand and are essential for the study of earthquakes.