Gravimeter

Definition

A gravimeter is a sensitive instrument used to measure variations in gravitational acceleration at different locations. This tool is essential in geophysical surveys, as it helps to detect subsurface structures, mineral deposits, and changes in geological formations by measuring the small differences in gravity caused by these features.

5 Must Know Facts For Your Next Test

1. Gravimeters can be classified into absolute and relative types, with absolute gravimeters providing precise measurements of gravitational acceleration and relative gravimeters measuring changes in gravity compared to a reference point.
2. High-precision gravimeters can detect variations as small as one part per billion, making them invaluable for detecting geological features such as oil fields or underground cavities.
3. Gravimeters are often used in conjunction with other geophysical methods, like seismic surveys or magnetic surveys, to provide a more comprehensive understanding of subsurface conditions.
4. The data collected from gravimeters can be used to create gravity anomaly maps, which help geophysicists identify areas of interest for further exploration or study.
5. Improvements in technology have led to portable and more user-friendly gravimeters, allowing for easier field deployment and faster data acquisition.

Review Questions

• How do gravimeters contribute to our understanding of subsurface geological structures?
  • Gravimeters measure small variations in gravitational acceleration, which are influenced by the density and composition of subsurface materials. By analyzing these variations, geophysicists can infer the presence of geological features such as mineral deposits, fault lines, or underground voids. This information is critical for resource exploration and environmental assessments.
• Compare and contrast absolute and relative gravimeters regarding their applications and measurement techniques.
  • Absolute gravimeters measure the gravitational acceleration at a specific location with high precision, providing accurate values that are essential for fundamental research in geophysics. In contrast, relative gravimeters focus on measuring differences in gravity between locations, making them useful for mapping gravity anomalies. While absolute gravimeters are typically used in controlled environments for precise scientific research, relative gravimeters are more often employed in field studies where quick comparisons are needed.
• Evaluate the significance of gravity anomaly maps derived from gravimeter data in resource exploration.
  • Gravity anomaly maps derived from gravimeter data play a crucial role in resource exploration by highlighting areas where subsurface materials deviate from expected gravitational values. These deviations can indicate the presence of valuable resources such as oil, gas, or minerals. By interpreting these maps, geophysicists can prioritize exploration efforts, reduce costs associated with drilling and surveying, and make informed decisions about where to allocate resources for further investigation.

Related terms

Gravity: The natural force that attracts two bodies towards each other, most commonly associated with the attraction between the Earth and objects on its surface.

Geophysical survey: A method of investigating the physical properties of the Earth using various techniques, including gravity measurements, to locate resources or understand geological structures.

Bouguer anomaly: The difference between observed gravity and a theoretical value based on a model of the Earth's gravity field, corrected for elevation and local topography.